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Question 1
Correct
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Where is Vitamin B12 mainly stored in the body?
Your Answer: Liver
Explanation:The total amount of vitamin B12 stored in body is about 2–5 mg in adults. Around 50% of this is stored in the liver. Approximately 0.1% of this is lost per day by secretions into the gut, as not all these secretions are reabsorbed.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 2
Correct
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Telomerase is active in all of the following cells, except:
Your Answer: Certain liver cells
Explanation:Telomerase is an enzyme that adds repetitive nucleotide sequences to the ends of chromosomes (telomeres), preventing their shortening during cell division. Telomerase activity is crucial for cells that divide frequently and need to maintain their telomere length for continued proliferation. These include:
- Stem cells: They have high telomerase activity to maintain their long-term proliferative capacity.
- Germ cells: These cells also have active telomerase to ensure the stability of genetic material across generations.
- Certain white blood cells: Some immune cells, particularly those that need to proliferate in response to infection, show telomerase activity.
- Certain cancer cells: Many cancer cells reactivate telomerase, which contributes to their uncontrolled growth and immortality.
However, most somatic cells, including certain liver cells, do not exhibit significant telomerase activity. While some liver cells might show low levels of telomerase activity during regeneration, it is not generally active in normal, differentiated liver cells.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 3
Incorrect
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Where does one find the thyroid receptors?
Your Answer: Golgi apparatus
Correct Answer: Cell nucleus
Explanation:Unlike many of the steroid receptors, inactive receptors for T3 are located in the nucleus. T4 is first converted into T3 within the cytoplasm of the cell, T3 then enters the nucleus and binds to its receptor. The hormone-receptor complex can now bind to DNA and activate specific genes.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 4
Incorrect
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Which of the following is a product of D cells
Your Answer: Trefoil peptides
Correct Answer: Somatostatin
Explanation:Somatostatin is secreted by D cells, HCL and intrinsic factor secreted by parietal cells. Trefoil peptides are secreted by mucus secreting goblet cells and gastrin releasing peptide (grp) by post-ganglionic fibers of the vagus nerve (which innervate the G cells of the stomach).
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 5
Incorrect
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The function of the Golgi apparatus is
Your Answer: Synthesis of steroid hormones
Correct Answer: Maturation of peptides secreted by the rER into functional proteins by glycosylation
Explanation:Steroidogenesis is a multi-step process that occurs in two organelles, the endoplasmic reticulum (ER) and the mitochondrion. The Golgi apparatus is a major collection and dispatch station of protein products received from the endoplasmic reticulum (ER). Proteins synthesized in the ER are packaged into vesicles, which then fuse with the Golgi apparatus. The majority of proteins synthesized in the rough ER undergo glycosylation which occurs in the Golgi apparatus. Glycosylation mainly refers in particular to the enzymatic process that attaches glycans to proteins, lipids, or other organic molecules. These cargo proteins are modified and destined for secretion via exocytosis or for use in the cell. The Golgi apparatus is also involved in lipid transport and lysosome formation.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 6
Incorrect
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A 50-year-old woman diagnosed with non-Hodgkin's Lymphoma is about to be started on the CHOP regimen (cyclophosphamide, hydroxydaunorubicin, vincristine, and prednisolone). Her pre-chemotherapy blood investigations show:Hb: 11.8 g/dlPlatelets: 423 x 109/lWBC: 11.2 x 109/lNa+: 143 mmol/lK+: 3.9 mmol/lUrea: 6.2 mmol/lCreatinine: 78 μmol/lUric acid: 0.45 mmol/lCiprofloxacin is prescribed in addition to the CHOP regimen to reduce the risk of neutropenic sepsis. Which of the following drugs should be added to lower the risk of other complications?
Your Answer: Aspirin
Correct Answer: Allopurinol
Explanation:Tumour lysis syndrome (TLS) occurs most notably in patients with haematological malignancies including, Non-Hodgkin’s Lymphoma (NHL) and Acute Lymphocytic Leukaemia (ALL).Risk factors for TLS include:• Large tumour burden• Sensitivity of the tumour to chemotherapy• Rapid tumour growth rateTLS is characterized by:• Hyperuricemia• Hyperkalaemia• Hyperphosphatemia• HypocalcaemiaTreatment of TLS:• Allopurinol: It is a xanthine oxidase inhibitor, it reduces the conversion of nucleic acid by-products to uric acid. Thus, it prevents urate nephropathy and subsequent oliguric renal failure. Note: dose reduction is essential in renal failure or if given along with mercaptopurine or azathioprine.Alternatives to Allopurinol: Febuxostat; Rasburicase are useful in patients with hyperuricemia.• Hydration• Diuresis: Should be considered in well hydrated patients with insufficient urine output. Furosemide to be considered in normo-volemic patients with hyperkalaemia. Urine alkalization can be considered for promoting alkaline diuresis.• Treatment of electrolyte imbalances including hyperkalaemia, hyperphosphatemia, and hypocalcaemia.• Dialysis can be considered in refractory cases.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 7
Incorrect
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An 81 year old male patient was admitted after an ischaemic stroke. Physical examination reveals left hemiparesis. How would you classify this hemiparesis based on the WHO International Classification of Functioning, Disability and Health?
Your Answer: Right total anterior circulation infarct
Correct Answer: Impairment of body function
Explanation:Symptoms and signs are classified as ‘impairment of body function’. The types of impairment classified as ‘activity limitation’ include difficulties that a patient may have in executing certain activities. The type of impairment classified as ‘participation restriction’ are problems a patient may have in social roles. The type of impairment classified as ‘pathology’ would be the diagnosis/disease. Right total anterior circulation infarct relates to the Oxford Bamford classification for stroke.
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This question is part of the following fields:
- Geriatrics
- Medicine
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Question 8
Incorrect
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Which of the following takes place during fasting
Your Answer: Basic electrical rhythm
Correct Answer: Migrating motor complex
Explanation:Migrating motor complexes (MMC) are waves of electrical activity that sweep through the intestines in a regular cycle during fasting. These motor complexes trigger peristaltic waves, which facilitate transportation of indigestible substances such as bone, fiber, and foreign bodies from the stomach, through the small intestine, past the ileocecal sphincter, and into the colon.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 9
Correct
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An elderly man presents with fever of 38°C and a very severe headache. His BP is 85/50 mm Hg. He has neck stiffness and photophobia. What is the most appropriate management?
Your Answer: CT head
Explanation:In elderly patients, symptoms suggestive of meningitis could be due to an intracranial mass lesion (such as abscess, tumour or an intracerebral haematoma). Therefore elderly patients are increased risk of cerebral herniation from an LP. A CT head should be done before an LP to exclude a mass lesion.
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This question is part of the following fields:
- Geriatrics
- Medicine
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Question 10
Incorrect
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Which is NOT a prognostic factor for patients with malignant melanoma?
Your Answer: Microsatellite metastasis
Correct Answer: Diameter of melanoma > 6 mm
Explanation:Features that affect prognosis are tumour thickness in millimetres (Breslow’s depth – the deeper the Breslow thickness the poorer the prognosis.), depth related to skin structures (Clark level – the level of invasion through the dermis), type of melanoma, presence of ulceration, presence of lymphatic/perineural invasion, presence of tumour-infiltrating lymphocytes (if present, prognosis is better), location of lesion, presence of satellite lesions, and presence of regional or distant metastasis. Malignant melanoma tends to grow radially before entering a vertical growth phase. The diameter it reaches has not been found to be a prognostic factor.
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This question is part of the following fields:
- Dermatology
- Medicine
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Question 11
Incorrect
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Choose the correct statement regarding trabecular bone:
Your Answer: Also known as spongy bone
Correct Answer: All of the options are correct
Explanation:Trabecular, spongy or cancellous bone. It is located inside the cortical bone and makes up around 20% of all bone in the body. It is made of spicules or plates with a high surface to volume ratio, where many cells sit on the surface of the end plates. It receives its nutrients from the extracellular fluid (ECF), exchanging about 10 mmol of calcium every 24 hours.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 12
Incorrect
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The TSH receptor produces its effects in the thyrocyte via:
Your Answer: The jak-stat pathway
Correct Answer: G-protein coupled activation of adenylyl cyclise and phospholipase c
Explanation:The thyrotropin receptor, also known as TSH receptor, responds to the thyroid stimulating hormone or thyrotropin to stimulate production of T3 and T4. It is a G protein-coupled receptor which leads to stimulation of phospholipase C and adenylyl cyclase, mediated by Gq/11 and Gs.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 13
Incorrect
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Majority of gastrinomas are found in the:
Your Answer: Oesophagus
Correct Answer: Duodenum
Explanation:A gastrinoma is a tumour in the pancreas or duodenum that secretes excess of gastrin leading to ulceration in the duodenum, stomach and the small intestine. It is usually found in the duodenum, although it may arise in the stomach or pancreas. Those occurring in the pancreas have a greater potential for malignancy. Most gastrinomas are found in the gastrinoma triangle; this is bound by the junction of cystic and common bile ducts, junction of the second and third parts of the duodenum, and the junction of the neck and body of the pancreas.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 14
Incorrect
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Coronary blood flow occurs in?
Your Answer: Corresponds with the P wave on ECG
Correct Answer: Diastole
Explanation:Coronary arteries are unique in that they fill during diastole, when not occluded by valve cusps nor compressed by myocardial contraction).
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 15
Correct
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Choose the correct statement regarding the protein C/S system?
Your Answer: The protein C/S complex inactivates factor Va and VIIIa
Explanation:The best characterized function of Protein S is its role in the anti coagulation pathway, where it functions as a cofactor to Protein C in the inactivation of Factors Va and VIIIa.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 16
Correct
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Which one of the following statements best describes a type II statistical error?
Your Answer: The null hypothesis is accepted when it is false
Explanation:In statistical hypothesis testing there are 2 types of errors:- type I: the null hypothesis is rejected when it is true – i.e. Showing a difference between two groups when it doesn’t exist, a false positive. – type II: the null hypothesis is accepted when it is false – i.e. Failing to spot a difference when one really exists, a false negative.
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This question is part of the following fields:
- Medicine
- Research Skills
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Question 17
Incorrect
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The tectum as part of the Midbrain contains which structure important in visual reflexes.
Your Answer: Cerebellum
Correct Answer: Superior colliculus
Explanation:The tectum is a part of the midbrain, specifically, the dorsal part of the midbrain. The tectum consists of the superior and inferior colliculi. The superior colliculus is involved in preliminary visual processing and control of eye movement.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 18
Incorrect
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Microfilaments exist in:
Your Answer: Non-muscle cells
Correct Answer: All of the options
Explanation:Microfilaments, also called actin filaments, are filamentous structures in the cytoplasm of cells and form part of the cytoskeleton.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 19
Correct
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An effect of aging on the kidney includes?
Your Answer: Decreased GFR
Explanation:The normal range of GFR, adjusted for body surface area, is 100 to 130 mL/min/1.73m2 in men and 90 to 120 ml/min/1.73m2 in women younger than the age of 40. After age 40, GFR decreases progressively with age, by about 0.4 mL/min to 1.2 mL/min per year.
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This question is part of the following fields:
- Medicine
- Renal
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Question 20
Incorrect
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Where in the gastrointestinal tract are Brunner glands?
Your Answer: Oesophagus
Correct Answer: Duodenum
Explanation:Brunner’s glands (or duodenal glands) are compound tubular submucosal glands found in that portion of the duodenum which is above the hepatopancreatic sphincter (aka sphincter of Oddi). The main function of these glands is to produce a mucus-rich alkaline secretion (containing bicarbonate) in order to:- protect the duodenum from the acidic content of chyme (which is introduced into the duodenum from the stomach);- provide an alkaline condition for the intestinal enzymes to be active, thus enabling absorption to take place; lubricate the intestinal walls.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 21
Incorrect
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A 22 year old nulliparous female presents with shortness of breath. She has a history of recurrent deep vein thrombosis. Complete blood count and clotting screen reveals the following results:Hb: 12.4 g/dl Plt: 137 WBC: 7.5*109/l PT: 14 secs APTT: 46 secs Which of the following would be the most likely diagnosis?
Your Answer: Antithrombin III deficiency
Correct Answer: Antiphospholipid syndrome
Explanation:The combination of APTT and low platelets with recurrent DVTs make antiphospholipid syndrome the most likely diagnosis.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 22
Incorrect
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Concerning protein digestion:
Your Answer: Maximal acid secretion correlates with pepsinogen 2
Correct Answer: Most protein digestion occurs in the duodenum
Explanation:Human pepsinogens can be divided into two immunochemically distinct groups: Pepsinogen I (PG I) and Pepsinogen II (PGII). PG I is secreted mainly by chief cells in the fundic mucosa whereas PGII is secreted by the pyloric glands and the proximal duodenal mucosa. Maximal acid secretion correlates with PG I. Most protein digestion occurs in the duodenum/jejunum. Pepsin functions best in an acidic environment and specifically at a pH of 1.5 to 3.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 23
Correct
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What is the function of secondary messengers?
Your Answer: Communication from extracellular to intracellular signalling pathways
Explanation:First messengers may not physically cross the phospholipid bilayer to initiate changes within the cell directly. This functional limitation necessitates the cell to devise signal transduction mechanisms to transduce first messenger into second messengers, so that the extracellular signal may be propagated intracellularly. Second messengers are intracellular signalling molecules released by the cell to trigger physiological changes such as proliferation, differentiation, migration, survival, and apoptosis. Secondary messengers are therefore one of the initiating components of intracellular signal transduction cascades.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 24
Incorrect
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During which phase are the 2 chromatids pulled apart at the centromere?
Your Answer: Metaphase
Correct Answer: Anaphase
Explanation:During the prometaphase the microtubule organizing centre completely develops. The spindle fibers attach to the chromosome and the centriole. It is in the Anaphase however that the spindle fibers contract pulling the sister chromatids apart. Later in the anaphase a cleave furrow beings to forms.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 25
Incorrect
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Question 26
Incorrect
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Eosinophils provide immunity against
Your Answer: Fungi
Correct Answer: Multi cellular parasites
Explanation:Eosinophils, are a variety of white blood cells and one of the immune system components responsible for combating multicellular parasites and certain infections in vertebrates.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 27
Correct
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Choose the correct answer: The interposed nuclei…
Your Answer: Are the emboliform and globose nuclei in the paravermis
Explanation:The interposed nuclei are a part of deep cerebellar complex and are composed of the globose nucleus and the emboliform nucleus. It receives afferent fibers from the anterior lobe of the cerebellum and sends output via the superior cerebellar peduncle to the red nucleus.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 28
Incorrect
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Which of the following factors is directly responsible for the breakdown of fibrinogen to fibrin?
Your Answer: Fibrinogen degradation products (FDPS)
Correct Answer: Thrombin
Explanation:Prothrombin (coagulation factor II) is proteolytically cleaved to form thrombin in the coagulation cascade, the clotting process. Thrombin in turn acts as a serine protease that converts soluble fibrinogen into insoluble strands of fibrin, as well as catalysing many other coagulation-related reactions.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 29
Correct
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What are the three main structures in the portal triad (portal space)?
Your Answer: Branch of hepatic artery, branch of portal vein, bile ductules
Explanation:A portal triad (also known as portal field, portal area, or portal tract) is a distinctive arrangement in the liver. It is a component of the hepatic lobule. It consists of the following five structures:
- Proper hepatic artery
- Hepatic portal vein
- Common bile duct
- Lymphatic vessels
- Branch of the vagus nerve
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This question is part of the following fields:
- Hepatobiliary
- Medicine
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Question 30
Correct
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Inhibition of cell division at the end of G1 occurs through:
Your Answer: Unphosphorolated retinoblastoma protein (uRb)
Explanation:A cell’s decision to enter, or re-enter, the cell cycle is made before S-phase in G1 at what is known as the restriction point, and is determined by the combination of promotional and inhibitory extracellular signals that are received and processed. Ultimately unphosphorylated Rb acts as an inhibitor of G1.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 31
Incorrect
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Choose the standard method for comparing distributions in data sets (such as between the expected frequency of an event and the observed frequency of an event) from the list of options.
Your Answer: Mean
Correct Answer: Chi squared (X²) test
Explanation:The Chi-squared test evaluates if two variables are related. The other statistical tests mentioned do not perform this function.
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This question is part of the following fields:
- Medicine
- Research Skills
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Question 32
Incorrect
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A 47 year old woman presents with joint pains and a history of recurrent infections over the past few months. Labs reveal a positive rheumatoid factor and low white cell count. Given the likely diagnosis, which of the following features would be present in her case?
Your Answer: Flexural surface rheumatoid nodules
Correct Answer: Splenomegaly
Explanation:Felty syndrome is a severe subtype of seropositive Rheumatoid arthritis. Clinical triad consists of arthritis, splenomegaly, and neutropenia (leads to an increased risk of recurrent bacterial infections). Other symptoms include skin ulcers of the lower limbs (indicating vasculitis), hepatomegaly, fever, and chest pain (indicating pleuritis or pericarditis). It is associated with increased risk of developing non-Hodgkin lymphoma.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 33
Incorrect
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The thalamic main input from the cortex is via which tracts?
Your Answer: Corticospinal tracts
Correct Answer: Thalamocortical pathway
Explanation:The thalamus is connected to cerebral cortex via the thalamocortical radiation.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 34
Correct
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Major supplies of glycogen are found in ….
Your Answer: Liver and skeletal muscle
Explanation:The two major sites of glycogen storage are the liver and skeletal muscle. The concentration of glycogen is higher in the liver than in muscle however more glycogen is stored in skeletal muscle due to its greater mass.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 35
Incorrect
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A 32 year old man presents with blistering and hyperpigmentation on his face and hands, after a beach holiday with friends. Tests reveal high levels of uroporphyrinogen in the urine. The most likely diagnosis is:
Your Answer: Acute intermittent porphyria
Correct Answer: Porphyria cutanea tarda
Explanation:Porphyria cutanea tarda (PCT) is the most common of the porphyries. It is characterised by fragility and blistering of exposed skin. Typically, patients who are ultimately diagnosed with PCT first seek treatment following the development photosensitivities in the form of blisters and erosions on commonly exposed areas of the skin. This is usually observed in the face, hands, forearms, and lower legs. It heals slowly and with scarring. Though blisters are the most common skin manifestations of PCT, other skin manifestations like hyperpigmentation (as if they are getting a tan) and hypertrichosis (mainly on top of the cheeks) also occur. Risk factors for the development of PCT include alcohol and sun.
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This question is part of the following fields:
- Dermatology
- Medicine
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Question 36
Incorrect
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Transportation of proteins from the cell body to axonal terminals is known as:
Your Answer: Antidromic conduction
Correct Answer: Axoplasmic flow
Explanation:Transportation of proteins from the cell body to axonal terminals is known as axoplasmic, axonal flow or Axonal transport.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 37
Correct
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The ependyma fuse with which of the following to from the choroid plexus?
Your Answer: Tela choroidea
Explanation:The choroid plexus produces the cerebrospinal fluid (CSF) in the ventricles of the brain. It consists of modified ependymal cells. Tela choroidea is a region of pia mater of the meninges and underlying ependyma that’s a part of the choroid plexus. It is a very thin layer of the connective tissue of pia mater that overlies and covers the ependyma.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 38
Incorrect
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A 82-year-old woman admitted following a fractured neck of femur has been discharged. On review, she is making good progress but consideration is given to secondary prevention of further fractures. What is the most appropriate step in the prevention of further fractures?
Your Answer: Arrange DEXA scan + start hormone replacement therapy if T-score < -2.5 SD
Correct Answer: Start oral bisphosphonate
Explanation:In such a clinical scenario, NICE guidelines support initiating treatment with bisphosphonates without waiting for a DEXA scan.Osteoporosis is defined as low bone mineral density caused by altered bone microstructure ultimately predisposing patients to low-impact, fragility fractures.Management:Vitamin D and calcium supplementation should be offered to all women unless the clinician is confident they have adequate calcium intake and are vitamin D repleteAlendronate is the first-line treatment. Around 25% of patients cannot tolerate alendronate, usually due to upper gastrointestinal problems. These patients should be offered risedronate or etidronate.Strontium ranelate and raloxifene are recommended if patients cannot tolerate bisphosphonates.Other medications that are useful in the treatment of osteoporosis are denosumab, teriparatide, raloxifene, etc.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 39
Incorrect
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Which of the following factors serve to decrease cardiac output?
Your Answer: Pregnancy
Correct Answer: Standing from a lying position
Explanation:Sleep has no effect on the cardiac output. Anxiety, excitement, increased body temperature and pregnancy will increase the cardiac output. Standing from a lying position will decrease the cardiac output transiently.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 40
Incorrect
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In RFLP (restriction fragment length polymorphism), the DNA fragments are separated by length through a process known as:
Your Answer: Deletion
Correct Answer: Agarose gel electrophoresis
Explanation:Samples of DNA from individuals are broken into pieces by restriction enzymes and the fragments are separated according to their lengths via gel electrophoresis. Although now largely obsolete due to the rise of inexpensive DNA sequencing technologies, RFLP analysis was the first DNA profiling technique inexpensive enough to see widespread application.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 41
Incorrect
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Which one of the following is necessary to activate plasminogen to plasmin?
Your Answer: Factor Va
Correct Answer: tPA
Explanation:In circulation, plasminogen adopts a closed, activation resistant conformation. Upon binding to clots, or to the cell surface, plasminogen adopts an open form that can be converted into active plasmin by a variety of enzymes, including tissue plasminogen activator (tPA), urokinase plasminogen activator (uPA), kallikrein, and factor XII (Hageman factor).
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This question is part of the following fields:
- Haematology
- Medicine
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Question 42
Incorrect
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The liver is the principal site for?
Your Answer: Storage of Vit C
Correct Answer: Storage of iron
Explanation:The liver mainly synthesizes proteins including albumin, globulins and coalgulative factors. Vitamin B12 is taken in via the diet and stored by the liver. Vitamin C is not stored and excessive vitamin C is excreted via urine. Liver is the main site of iron storage, where it is stored in the form of ferritin.
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This question is part of the following fields:
- Hepatobiliary
- Medicine
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Question 43
Correct
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Normally the portal venous pressure is about:
Your Answer: 5mmhg
Explanation:Under normal physiological conditions, the pressure in the portal vein, which carries blood from the gastrointestinal tract and spleen to the liver, typically ranges around 5-10 mmHg. Pressures significantly higher than this range can indicate portal hypertension, which can be associated with liver diseases such as cirrhosis.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 44
Incorrect
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The net effect of parathyroid hormone on calcium and phosphate homeostasis is?
Your Answer: Increase in Ca, no net effect on phosphate
Correct Answer: Increase in Ca, decrease in phosphate
Explanation:Parathyroid hormone’s main target organs are the kidneys, bone, and intestine. In the kidney, it decreases reabsorption of phosphate and increases calcium reabsorption. It also promotes absorption of calcium from bone. PTH release results in a small drop in serum phosphate concentrations.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 45
Correct
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Question 46
Incorrect
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Which of the following do not pass through the cavernous sinus?
Your Answer: CN 6
Correct Answer: CN 2
Explanation:Oculomotor nerve (N3), trochlear nerve (N4), ophthalmic and mandibular divisions of the trigeminal nerve (N5) pass along its lateral border. The abducent nerve (N6) passes through it along with the internal carotid artery.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 47
Correct
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Osteopetrosis occurs as a result of a defect in:
Your Answer: Osteoclast function
Explanation:It is a metabolic bone disease caused by defective osteoclastic resorption of immature bone. Osteopetrosis is also known as marble bone disease. Osteoclasts are unable to adequately acidify bone matrix. Impaired bone resorption leads to overly dense bone that is more likely to fracture. It is usually treated with bone marrow transplant and high dose calcitriol.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 48
Correct
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Where do the spinothalamic axons decussate?
Your Answer: Spinal cord
Explanation:The second order neurons from the spinothalamic tract cross obliquely to the opposite side in the anterior grey and white commissure within one segment of the spinal cord.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 49
Incorrect
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When 2 nucleotide chains of DNA bind together, thymine is bound to:
Your Answer: Hydrogen
Correct Answer: Adenine
Explanation:As a general rule in the structure of DNA, thymine always binds to adenine with two hydrogen bonds, cytosine always binds to guanine with three hydrogen bonds and vice versa. However In the structure of RNA the only difference is that adenine binds to uracil instead of thymine. But thymine will always bind to adenine.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 50
Incorrect
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A 75 year old man presented to hospital after suffering a stroke. The doctor admitted him and advised of the Barthel score index. During rehabilitation, which one of the following limitations are best described by Barthel score index?
Your Answer: It is not very sensitive
Correct Answer: Floor and ceiling effects
Explanation:Barthel scoring has floor and ceiling effects which is the most widely recognised limitation. Floor effect means that the patient who is bed bound can score initially low, whereas the ceiling effect shows that despite being bed bound, a patient can achieve a maximum score i.e. 100. The test is easy to perform and correlates well with other prognostic scales.
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This question is part of the following fields:
- Geriatrics
- Medicine
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Question 51
Incorrect
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Which of the following is responsible for converting inactive cortisone to active cortisol in the adrenal gland?
Your Answer: 11βHSD type 2
Correct Answer: 11βHSD type 1
Explanation:11β-Hydroxysteroid dehydrogenase, also known as HSD-11β or 11β-HSD, is a group of enzymes which catalyse the interconversion of active cortisol and corticosterone with inert cortisone and 11-dehydrocorticosterone.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 52
Incorrect
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Which of the following cells are attracted to the surface of endothelium by selectins?
Your Answer: Lymphocytes
Correct Answer: Neutrophils
Explanation:Selectins are expressed on the surface of the endothelium. P selectins are released from weibel-palade bodies and E selectins are induced by cytokines (TNF and IL-1). They bind to receptors on the neutrophils called saiyl lewis X.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 53
Incorrect
-
Which clotting factor is responsible for stabilization of the fibrin clot by formation of covalent cross-linkages?
Your Answer: Factor XIIa
Correct Answer: Factor XIIIa
Explanation:Factor XIII or fibrin stabilizing factor is an enzyme of the blood coagulation system that crosslinks fibrin. Deficiency of this factor (FXIIID) affects clot stability.
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This question is part of the following fields:
- Haematology
- Medicine
-
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Question 54
Incorrect
-
Which one of the following conditions is least likely to be associated with pyoderma gangrenosum?
Your Answer: Rheumatoid arthritis
Correct Answer: Syphilis
Explanation:The following are conditions commonly associated with pyoderma gangrenosum:
Inflammatory bowel disease:
- Ulcerative colitis
- Crohn’s disease
Arthritides:
- Rheumatoid arthritis
- Seronegative arthritis
Haematological disease:
- Myelocytic leukaemia
- Hairy cell leukaemia
- Myelofibrosis
- Myeloid metaplasia
- Monoclonal gammopathy
Autoinflammatory disease:
- Pyogenic sterile arthritis, pyoderma gangrenosum, and acne syndrome (PAPA syndrome)
- Granulomatosis with polyangiitis
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This question is part of the following fields:
- Dermatology
- Medicine
-
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Question 55
Correct
-
Where is the normal upper border of the liver situated?
Your Answer: 6th rib midclavicular line on right
Explanation:Assessment of liver margins is important clinically to determine the size of the liver and is done via percussion during the physical examination. The liver typically extends from the fifth intercostal space or 6th rib to the right costal margin in the midclavicular line and the 10th rib on anterior axillary line.
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This question is part of the following fields:
- Hepatobiliary
- Medicine
-
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Question 56
Incorrect
-
The cavernous sinus is?
Your Answer: In the maxilla
Correct Answer: Lateral to the body of the sphenoid
Explanation:It is a venous sinus which creates a cavity called the lateral sellar compartment bordered by the temporal bone and the sphenoid bone. There are 2 on either side. It is about 1cm wide and extends from the posterior aspect of the orbit to the petrous part of the temporal bone. They sit on either side or lateral to the sphenoid bone.
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This question is part of the following fields:
- Medicine
- Neurology
-
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Question 57
Incorrect
-
A 75-year-old man has presented to the clinic with a complaint of disturbed sleep. The physician has prescribed temazepam. Which of the following best describes the mechanism of action of this drug?
Your Answer: Inhibits the effect of noradrenaline
Correct Answer: Enhances the effect of gamma-aminobutyric acid
Explanation:Temazepam is an orally available benzodiazepine used in the therapy of insomnia. The soporific activity of the benzodiazepines is mediated by their ability to enhance gamma-aminobutyric acid (GABA) mediated inhibition of synaptic transmission through binding to the GABA-A receptor.The recommended initial dose for insomnia is 7.5 mg before bedtime, increasing as needed to a maximum dose of 30 mg. The most common side effects of temazepam are dose-related and include daytime drowsiness, lethargy, ataxia, dysarthria, and dizziness.Tolerance develops to these side effects, but tolerance may also develop to the effects on insomnia.
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This question is part of the following fields:
- Medicine
- Pharmacology
-
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Question 58
Correct
-
Regarding transportation of iron in the body, the process in which iron is transported from the enterocyte into the blood occurs using which transporter protein:
Your Answer: Ferroportin
Explanation:Divalent metal transporter 1 (DMT1) transport several divalent metals including iron across the enterocyte’s cell membrane into the cell. The cell can then release it into the body via the only known iron exporter in mammals, ferroportin.
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This question is part of the following fields:
- Haematology
- Medicine
-
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Question 59
Incorrect
-
Cytochrome p450 enzymes expressed in hepatocytes serve to?
Your Answer: Induce the synthesis of acute phase proteins.
Correct Answer: Facilitate oxidations or hydrolysis of drugs.
Explanation:Cytochrome p 450 are a family of proteins involved in drug metabolism which accounts for about 75% of the total metabolism. Most drugs are deactivated directly or by facilitated excretion from the body.
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This question is part of the following fields:
- Hepatobiliary
- Medicine
-
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Question 60
Incorrect
-
What percentage of blood to the liver is supplied by hepatic artery?
Your Answer: Depends on the demand of the liver
Correct Answer: 25%
Explanation:The liver receives a dual blood supply from the hepatic portal vein and hepatic arteries. The hepatic portal vein delivers approximately 75% of the liver’s blood supply, and carries venous blood drained from the spleen, gastrointestinal tract, and its associated organs. The hepatic arteries supply arterial blood to the liver, accounting for the remaining quarter of its blood flow.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
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Question 61
Incorrect
-
A patient has been diagnosed with multi-drug resistant tuberculosis and is currently bring treated with rifampicin, isoniazid, and pyrazinamide. He is commenced on streptomycin.Which among the following is the most likely neurological side-effect of streptomycin?
Your Answer: Cochlear damage
Correct Answer: Vestibular damage
Explanation:Vestibular damage is a neurological side effect of streptomycin.Streptomycin is an aminoglycoside bactericidal antibiotic. It is used in the treatment of tularaemia and resistant mycobacterial infections.The most common neurological side-effect is vestibular damage leading to vertigo and vomiting. Cochlear damage is less frequent and results in deafness. Other side-effects include rashes, angioneurotic oedema, and nephrotoxicity.
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This question is part of the following fields:
- Medicine
- Pharmacology
-
-
Question 62
Incorrect
-
A 35-year-old woman under treatment for long-term epilepsy with valproate presented with complaints of excessive weight gain. She is consuming oral contraceptive pills.Which among the following is the best alternative to valproate for treating long-term epilepsy?
Your Answer: Phenobarbital
Correct Answer: Lamotrigine
Explanation:Among the given anti-epileptics the best drug that can be given in this patient is lamotrigine.Topiramate, carbamazepine, phenytoin, and phenobarbital are all hepatic enzyme inducers and are associated with decreased effectiveness of the oral contraceptive (OCP) due to acceleration of the metabolism of oestrogens and progestogens.If she is planning on pregnancy then registry studies suggest that lamotrigine would also be the best choice.Other hepatic enzyme inducers include rifampicin, spironolactone, griseofulvin, etc.
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This question is part of the following fields:
- Medicine
- Pharmacology
-
-
Question 63
Incorrect
-
The percentage of blood supplied to the liver by the hepatic artery is?
Your Answer: 45%
Correct Answer: 25%
Explanation:The liver receives a dual blood supply from the hepatic portal vein and hepatic arteries. The hepatic portal vein delivers approximately 75% of the liver’s blood supply, and carries venous blood drained from the spleen, gastrointestinal tract, and its associated organs. The hepatic arteries supply arterial blood to the liver, accounting for the remaining quarter of its blood flow. Oxygen is provided from both sources; approximately half of the liver’s oxygen demand is met by the hepatic portal vein, and half is met by the hepatic arteries
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This question is part of the following fields:
- Hepatobiliary
- Medicine
-
-
Question 64
Incorrect
-
Carbohydrates digestion starts in the
Your Answer: Stomach
Correct Answer: Mouth
Explanation:Digestion begins in the mouth with the secretion of saliva and its digestive enzymes. Food is formed into a bolus by the mechanical mastication and swallowed into the oesophagus from where it enters the stomach through the action of peristalsis.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
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Question 65
Incorrect
-
The pathway responsible for the discriminative aspect of pain, is called the:
Your Answer: Ventrolateral tract
Correct Answer: Neospinothalamic tract
Explanation:The spinothalamic tract is an ascending or a sensory tract, responsible for transmission of pain and temperature. The neospinothalamic tract is responsible for fast pain or discriminative pain whereas the palaeospinothalamic tract is responsible for transmission of slow pain.
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This question is part of the following fields:
- Medicine
- Neurology
-
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Question 66
Incorrect
-
Which one of the following is least associated with photosensitivity?
Your Answer: Psoriasis
Correct Answer: Acute intermittent porphyria
Explanation:Sunlight, especially its ultraviolet radiation component, can cause increased or additional types of damage in predisposed individuals, such as those taking certain phototoxic drugs, or those with certain conditions associated with photosensitivity, including:- Psoriasis- Atopic eczema- Erythema multiforme- Seborrheic dermatitis- Autoimmune bullous diseases (immunobullous diseases)- Mycosis fungoides- Smith–Lemli–Opitz syndrome- Porphyria cutanea tardaAlso, many conditions are aggravated by strong light, including:- Systemic lupus erythematosus- Sjögren’s syndrome- Sinear Usher syndrome- Rosacea- Dermatomyositis- Darier’s disease- Kindler-Weary syndromeAcute intermittent porphyria (AIP) belongs to the group inborn errors of metabolism and most patients with AIP are not light sensitive.
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This question is part of the following fields:
- Dermatology
- Medicine
-
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Question 67
Incorrect
-
The predominant site in the lymph node where B lymphocytes are found is:
Your Answer: Paracortex
Correct Answer: Cortex
Explanation:The cortex of the lymph node consists of the lymphoid nodules and sinusoids and posses a germinal centre from which B cells proliferate. The cortex of the lymph node predominately consists of B cells.
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This question is part of the following fields:
- Immunology
- Medicine
-
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Question 68
Correct
-
With regard to the cell membrane:
Your Answer: It consists of an outer hydrophilic & an inner hydrophobic layer
Explanation:The cell membrane consists primarily of a thin layer of amphipathic phospholipids that spontaneously arrange with the hydrophobic tail regions on the inside and the hydrophilic head regions outside. Membranes typically have a large content of proteins, around 50% of membrane volume.
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This question is part of the following fields:
- Cell Biology
- Medicine
-
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Question 69
Incorrect
-
Excitation-contraction coupling in cardiac muscle involves all of the following except:
Your Answer: Ca2+ conductance via the dihydropyridine receptor
Correct Answer: Binding of Ca2+ to calmodulin
Explanation:In the excitation contraction coupling model, an action potential is transmitted to the fibrils of a fiber through the T tubule system. It triggers the release of Ca 2+ from the terminal cisterns. Depolarization of the T tubules activates the sarcoplasmic reticulum through the dihydropyridine receptors. These are voltage gates calcium channels. Calcium binds to calmodulin during contraction of the smooth muscle and not the cardiac muscles.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 70
Incorrect
-
Interruption of the entero-hepatic circulation causes:
Your Answer: General malabsorption
Correct Answer: The amount of fat in the stool to be increased
Explanation:Enterohepatic circulation refers to the circulation of biliary acids, bilirubin, drugs, or other substances from the liver to the bile, followed by entry into the small intestine, absorption by the enterocyte and transport back to the liver. One of the causes of the interruption of enterohepatic circulation is the resection of the ileum where fat is mainly absorbed. Fat malabsorption results in increased fat in stools. Pale stools and dark urine is caused by obstruction of the biliary ductal system especially the common bile duct where urobilin and stercobilin are formed.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
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Question 71
Incorrect
-
A 36 year old man arrives at the clinic complaining of pain and swelling of the left knee, ankles and right hallux. He has acute conjunctivitis, and dysuria. He suffered from an episode of gastroenteritis two weeks back. Clinical examination shows left Achilles tendonitis and right plantar fasciitis. Radiological examination reveals left sacroiliitis, with evidence of enthesitis, joint erosions and periostitis. HLA-B27 is positive. Which of the following is the most likely diagnosis?
Your Answer: Ankylosing spondylitis
Correct Answer: Reiter’s syndrome
Explanation:Reactive arthritis, (formerly known as Reiter’s syndrome), is an autoimmune condition that occurs after a bacterial infection of the gastrointestinal or urinary tract. It is categorized as a seronegative spondylarthritis because of its association with HLA-B27. Reactive arthritis primarily affects young men and usually presents with musculoskeletal or extra‑articular symptoms. The characteristic triad consists of arthritis, conjunctivitis, and urethritis. The diagnosis is based on clinical features such as patient history and physical examination; there are no specific tests for reactive arthritis. Treatment is primarily symptomatic and consists of the administration of NSAIDs, as most patients recover spontaneously. extraarticular dermatologic manifestations include skin lesions of the glans resembling psoriasis (balanitis circinata); hyperkeratinisation of the palms and soles (keratoderma blenorrhagicum), oral ulcers.
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This question is part of the following fields:
- Connective Tissue
- Medicine
-
-
Question 72
Incorrect
-
Oxidation is defined as a:
Your Answer: Addition of protons to substances
Correct Answer: Loss of electrons from molecules
Explanation:Oxidation is the loss of electrons or an increase in oxidation state by a molecule, atom, or ion.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 73
Incorrect
-
Blood flow to the subendocardial portions of the left ventricular muscle occurs mainly during:
Your Answer: Isovolumetric ventricular contraction
Correct Answer: Diastole
Explanation:The sub endocardium receives the least amount of blood from the coronary arteries. During systole the coronary arteries collapse as a result of the pressure from contraction that is exerted on them. During diastole the heart muscle relaxes and the pressure on the coronary vessels is relieved allowing blood to flow through them to the sub endocardium.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 74
Incorrect
-
With regard to X linked disorders which of the following are true
Your Answer: They are relatively common but their expression is variable
Correct Answer: X linked recessive disorders usually present in males and only very rarely present in homozygous females
Explanation:All are true for autosomal recessive disorders. Dominance rules for sex-linked gene loci are determined by their behaviour in the female: because the male has only one allele (except in the case of certain types of Y chromosome aneuploidy), that allele is always expressed regardless of whether it is dominant or recessive.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 75
Incorrect
-
A case-control study is being designed to look at the relationship between eczema and a new vaccine for yellow fever. What is the usual outcome measure in a case-control study?
Your Answer: Numbers needed to harm
Correct Answer: Odds ratio
Explanation:A case–control study (also known as case–referent study) is a type of observational study in which two existing groups differing in outcome are identified and compared on the basis of some supposed causal attribute. Case–control studies are often used to identify factors that may contribute to a medical condition by comparing subjects who have that condition/disease (the cases) with patients who do not have the condition/disease but are otherwise similar (the controls).An odds ratio (OR) is a statistic that quantifies the strength of the association between two events, A and B. The odds ratio is defined as the ratio of the odds of A in the presence of B and the odds of A in the absence of B or vice versa.
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This question is part of the following fields:
- Medicine
- Research Skills
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Question 76
Incorrect
-
The function of ATP in cardiac muscle contraction includes:
Your Answer: Cross linkage of actin and myosin
Correct Answer: Binding to myosin after the power stroke to allow uncoupling of actin and myosin
Explanation:After calcium binds to the troponin C, there is a conformational change in the structure of troponin I and tropomyosin, which moves out of the way and frees the site where myosin can bind to actin. This results in the formation of the cross linkage of the actin and myosin giving rise to the power stroke in the contraction phase. This occurs with the release of ADP. When ATP combines to this complex it breaks and the cycle repeats itself.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 77
Incorrect
-
During strenuous exercise the following arterial change can take place in a fit athlete:
Your Answer: Oxygen can decrease
Correct Answer: No change takes place
Explanation:The changes which occur in arterial pH, PO2 and PCO2 values during exercise are usually small. Arterial PO2 often rises slightly because of hyperventilation although it may eventually fall at high work rates. During vigorous exercise, when sufficient oxygen for flux through the Krebs cycle is not available, the increased reliance on glycolysis results in increased accumulation of lactic acid, which initially leads to an increase in PaCO2 . However, this is counteracted by the stimulation of ventilation and as a result PaCO2 is decreased. This provides some respiratory compensation for further lactic acid production and prevents a decline in blood pH, which remains nearly constant during moderate exercise.
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This question is part of the following fields:
- Medicine
- Respiratory
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Question 78
Correct
-
The thalamic nuclei that project over wide regions of the neocortex are:
Your Answer: Specific relay nuclei
Explanation:The thalamus is considered the relay station for sensory and motor stimuli. There are three basic types of thalamic nuclei: relay nuclei, association nuclei and non-specific nuclei. Relay nuclei receive very well defined inputs and project this signal to functionally distinct areas of the cerebral cortex. These include the nuclei that relay primary sensations and also the nuclei involved in feedback of cerebellar signals and basal gangliar output.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 79
Incorrect
-
In blistering dermatological disorders e.g.. Pemphigus, which junctions are attacked by autoantibodies?
Your Answer: Tight junctions
Correct Answer: Desmosomes
Explanation:Pemphigus is an autoimmune disease caused by antibodies directed against both desmoglein 1 and desmoglein 3 present in desmosomes. Loss of desmosomes results in loss of cohesion between keratinocytes in the epidermis, and a disruption of the barrier function served by intact skin. The process is classified as a type II hypersensitivity reaction
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 80
Incorrect
-
The oligosaccharidases responsible for further digestion of starch after breakdown by the above mentioned enzymes is located where?
Your Answer: Colon
Correct Answer: Brush border of small intestine
Explanation:The final step in digestion of carbohydrates, which is conversion of disaccharides to absorbable monosaccharides occurs on the small intestinal epithelial cells. The enzymes responsible for this final stage of digestion are not freely found in the intestinal lumen, but they are found as integral membrane proteins in the plasma membrane of the epithelial cell. The apical plasma membrane of the intestinal epithelial cell has numerous microvilli known as the brush border. Thus, the enzymes embedded in those microvilli are referred to as brush border enzymes.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
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Question 81
Incorrect
-
The approximate incidence of deep venous thrombosis (DVT) in the general population each year is:
Your Answer: 50 per 1000
Correct Answer: 1 per 1000
Explanation:About 1 in 1000 adults per year has DVT, but as of 2011, available data is dominated by North American and European populations. DVT is rare in children, with an incidence of about 1 in 100,000 a year. From childhood to old age, incidence increases by a factor of about 1000, with almost 1% of the elderly experiencing DVTs yearly.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 82
Incorrect
-
Which of the following cancers is responsible in producing osteoblastic bone metastases instead of osteolytic?
Your Answer: Endometrial adenocarcinoma
Correct Answer: Prostate adenocarcinoma
Explanation:Osteoblastic (or sclerotic) bone metastases, characterized by deposition of new bone, present in prostate cancer, carcinoid, small cell lung cancer, Hodgkin lymphoma or medulloblastoma.
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This question is part of the following fields:
- Connective Tissue
- Medicine
-
-
Question 83
Incorrect
-
The conversion of haem to bilirubin is catalysed by which of these enzymes?
Your Answer: Gamma glutamyl transpeptidase
Correct Answer: Biliverdin reductase
Explanation:Bilirubin is created by the activity of biliverdin reductase on biliverdin, a green tetrapyrrolic bile pigment that is also a product of haem catabolism.
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This question is part of the following fields:
- Hepatobiliary
- Medicine
-
-
Question 84
Incorrect
-
Drug-induced lupus erythematosus most often occurs after taking which of the following drugs?
Your Answer: Isoniazid
Correct Answer: Procainamide
Explanation:Many drugs are responsible for causing drug induced lupus. However, it is most commonly associated with hydralazine, procainamide and quinidine.
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This question is part of the following fields:
- Connective Tissue
- Medicine
-
-
Question 85
Incorrect
-
HCL is secreted by which cells in the stomach
Your Answer: G cells
Correct Answer: Parietal cells
Explanation:Parietal cells are the epithelial cells that secrete hydrochloric acid (HCl) and intrinsic factor. These cells are located in the gastric glands found in the lining of the fundus and in the body of the stomach.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
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Question 86
Incorrect
-
Where is most of the filtered sodium reabsorbed?
Your Answer: It is absorbed the same everywhere
Correct Answer: Proximal tubule
Explanation:Renal reabsorption of sodium (Na+) is a part of renal physiology. It uses Na-H antiport, Na-glucose symport, sodium ion channels (minor). It is stimulated by angiotensin II and aldosterone, and inhibited by atrial natriuretic peptide. Most of the reabsorption (65%) occurs in the proximal tubule.
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This question is part of the following fields:
- Medicine
- Renal
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Question 87
Incorrect
-
The brainstem contains which of the following structures?
Your Answer: The subthalamus, midbrain and pons
Correct Answer: The midbrain, pons and medulla
Explanation:Brain stem is the base of the brain that connects the brain to the spinal cord. It consists of the mid brain, pons and medulla oblongata.
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This question is part of the following fields:
- Medicine
- Neurology
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-
Question 88
Incorrect
-
Where in the course of the gastrointestinal tract does the first significant digestion of fat begin in a normal human being?
Your Answer: Stomach
Correct Answer: Duodenum
Explanation:The enzyme lipase which is responsible for digestion of fat is secreted by the exocrine pancreas in the 2nd part of the duodenum at the point where the pancreatic duct opens. It opens together with the common bile duct which contains bile that emulsify fat aiding in digestion. The oesophagus, stomach and mouth do not contain enzymes related to fat digestion.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 89
Incorrect
-
What percentage of blood is supplied to the liver by the portal vein?
Your Answer: 45%
Correct Answer: 75%
Explanation:The portal vein supplies 75% of the blood to the liver and exceeds the arterial supply of the organ.
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This question is part of the following fields:
- Hepatobiliary
- Medicine
-
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Question 90
Incorrect
-
Which one of the following interventions has the least role in management of acne rosacea?
Your Answer: Topical metronidazole
Correct Answer: Low-dose topical corticosteroids
Explanation:Mild cases are often not treated at all, or are simply covered up with normal cosmetics and avoiding sun exposure. Therapy for the treatment of rosacea is not curative, and is best measured in terms of reduction in the amount of facial redness and inflammatory lesions. The two primary modalities of rosacea treatment are topical and oral antibiotic agents (including metronidazole and tetracyclines). Laser therapy may be appropriate for patients with prominent telangiectasia.
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This question is part of the following fields:
- Dermatology
- Medicine
-
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Question 91
Incorrect
-
A 56 year old obese female presents due to moderate pain in her finger joints which occurs mostly at the end of the day which gets better with rest. There is also some associated swelling. On examination, there is enlargement of her distal interphalangeal joints and tenderness to palpation. Which of the following is the most likely diagnosis?
Your Answer: Gout
Correct Answer: Osteoarthritis
Explanation:Osteoarthritis (OA) is a disabling joint disease characterized by a noninflammatory degeneration of the joint complex (articular cartilage, subchondral bone, and synovium) that occurs with old age or from overuse. It mainly affects the weight-bearing and high-use joints, such as the hip, knee, hands, and vertebrae. Despite the widespread view that OA is a condition caused exclusively by degenerative “wear and tear” of the joints, newer research indicates a significant heterogeneity of causation, including pre-existing peculiarities of joint anatomy, genetics, local inflammation, mechanical forces, and biochemical processes that are affected by proinflammatory mediators and proteases. Major risk factors include advanced age, obesity, previous injuries, and asymmetrically stressed joints. In early-stage osteoarthritis, patients may complain of reduced range of motion, joint-stiffness, and pain that is aggravated with heavy use. As the disease advances, nagging pain may also occur during the night or at rest. Diagnosis is predominantly based on clinical and radiological findings. Classic radiographic features of OA do not necessarily correlate with clinical symptoms and appearance. RA involves proximal interphalangeal joints not distal. Gout occurs as a result of overproduction or underexcretion of uric acid and frequently involves first toe. Fibromyalgia is a disorder characterized by widespread musculoskeletal pain accompanied by fatigue, sleep, memory and mood issues.
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This question is part of the following fields:
- Connective Tissue
- Medicine
-
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Question 92
Incorrect
-
Cold receptors are likely to be active at the following temperatures except?
Your Answer: 19 °C
Correct Answer: 39 °C
Explanation:Cold and Menthol receptor 1 (CMR1) is a protein that in humans is encoded by TRPM8 gene. It is primarily responsible for the detection of temperatures ranging from 8-28 C. It is an ion channel which upon activation causes the influx of Na+ and Ca+ ions into the cell that leads to the depolarization and generation of an action potential.
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This question is part of the following fields:
- Medicine
- Neurology
-
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Question 93
Incorrect
-
A 27-year-old male is admitted after drinking engine coolant in an apparent suicide attempt. Lab investigations reveal:
- pH 7.1 (7.36-7.44)
- pO2 15.3 kPa (11.3-12.6)
- pCO2 3.2 kPa (4.7-6.0)
- Standard bicarbonate 2.2 mmol/L (20-28)
- Serum calcium 1.82 mmol/L (2.2-2.6)
Your Answer: 8.4% bicarbonate infusion
Correct Answer: Fomepizole infusion
Explanation:The patient’s symptoms and lab results are indicative of ethylene glycol poisoning, commonly found in engine coolant. Ethylene glycol is metabolized to toxic metabolites, including glycolic acid and oxalic acid, which can cause metabolic acidosis (evidenced by the low pH and low bicarbonate levels) and can bind calcium, leading to hypocalcemia.
Fomepizole is an antidote that inhibits alcohol dehydrogenase, the enzyme that converts ethylene glycol into its toxic metabolites. This prevents further formation of the harmful substances, allowing time for the ethylene glycol to be excreted unchanged in the urine.
While haemodialysis is also an important treatment for severe ethylene glycol poisoning, especially in cases of significant acidosis or renal failure, the immediate administration of fomepizole is the most urgent intervention to prevent further toxicity. Haemodialysis can be considered if the patient does not respond adequately to fomepizole or if there are signs of severe toxicity.
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This question is part of the following fields:
- Medicine
- Pharmacology
-
-
Question 94
Incorrect
-
In which of the following are the enzymatic mechanisms for producing aldosterone found?
Your Answer: Androgen producing cells
Correct Answer: Zona glomerulosa
Explanation:The zona glomerulosa is the outermost layer of the adrenal gland. In it, aldosterone is secreted as a response to an increase in potassium levels, decreased blood flow, or renin. This secretion is regulated by the renin-angiotensin system.
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This question is part of the following fields:
- Endocrinology
- Medicine
-
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Question 95
Incorrect
-
A 27-year-old female diagnosed with rheumatoid arthritis has failed to respond to methotrexate and sulfasalazine. Her GP decides to start her on etanercept injections. Which one among the following is an adverse effect associated with the use of etanercept?
Your Answer: Cardiomyopathy
Correct Answer: Reactivation of tuberculosis
Explanation:Among the give options, reactivation of tuberculosis may occur in a patient under treatment with etanercept.Etanercept is a biological TNF inhibit commonly used to control ankylosing spondylitis, juvenile idiopathic arthritis, plaque psoriasis, psoriatic arthritis, and rheumatoid arthritis.Etanercept is a soluble receptor that binds both TNF-alpha and TNF-beta to inhibit the inflammatory response in joints and skin that is characteristic of these autoimmune disorders.The most common adverse effects include infections (viral, bacterial, and fungal – mostly upper respiratory tract infections) and injection site reaction (erythema, itching, pain, swelling, bleeding, bruising).Rarely it can also cause, reactivation of hepatitis B and TB, pneumocystis pneumonia, congestive cardiac failure, Steven-Johnson syndrome, toxic epidermal necrolysis, etc.
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This question is part of the following fields:
- Medicine
- Pharmacology
-
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Question 96
Incorrect
-
Which of the following statements are true regarding human herpesvirus eight
Your Answer: It may the associated with myeloproliferative disorders.
Correct Answer: It is sexually transmitted.
Explanation:Kaposi’s sarcoma-associated herpesvirus (KSHV) is the eighth human herpesvirus or HHV-8. This virus causes Kaposi’s sarcoma, a cancer commonly occurring in AIDS patients, as well as primary effusion lymphoma and some types of multicentric Castleman’s disease. It is one of seven currently known human cancer viruses, or oncoviruses. The mechanisms by which the virus is contracted are not well understood. Healthy individuals can be infected with the virus and show no signs or symptoms, due to the immune system’s ability to keep the infection in check. Infection is of particular concern to the immunosuppressed. Cancer patients receiving chemotherapy, AIDS patients and organ transplant patients are all at a high risk of showing signs of infection. The virus is sexually transmitted.
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This question is part of the following fields:
- Infectious Diseases
- Medicine
-
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Question 97
Correct
-
Which is primarily responsible for the conversion of T4 to T3 in the periphery?
Your Answer: Deiodinase 1
Explanation:Type 1 iodothyronine deiodinase, also known simply as deiodinase 1, is an enzyme which can produce both triiodothyronine (active form) or inactivate metabolites from T4. It is responsible for almost 80% of the conversion of peripheral T4 to T3. Iodothyronine deiodinases are not to be confused with iodotyrosine deiodinases, which are also part of the deiodinase enzymes.
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This question is part of the following fields:
- Endocrinology
- Medicine
-
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Question 98
Incorrect
-
Concerning surface anatomy, where is the base of the heart
Your Answer: 6th intercostal space mid clavicular line
Correct Answer: 2nd left costal to 3rd right costal cartilage
Explanation:The base of the heart, also known as the superior border of the heart corresponds to a line connecting the inferior border of the 2nd left costal cartilage to the superior border of the 3rd right costal cartilage.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 99
Incorrect
-
Regarding glomus cells, which of the following is true?
Your Answer: Have one neurotransmitter - acetylcholine.
Correct Answer: Contain catecholamines
Explanation:The carotid body detects changes in the composition of arterial blood flowing through it, mainly the partial pressure of oxygen, but also of carbon dioxide. Furthermore, it is also sensitive to changes in pH and temperature.The carotid body is made up of two types of cells, called glomus cells: Glomus type I/chief cells release a variety of neurotransmitters, including acetylcholine, ATP, and dopamine that trigger EPSPs in synapsed neurons leading to the respiratory centre.Glomus type II/sustentacular cells resemble glia, express the glial marker S100 and act as supporting cells.
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This question is part of the following fields:
- Medicine
- Respiratory
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Question 100
Incorrect
-
A 60-year-old male is under treatment with azathioprine after a renal transplant. During his review, he complains of pain and swelling over his left great toe. Investigations reveal hyperuricemia. Suspecting gout, he was started on allopurinol. Subsequently, he develops aplastic anaemia. Which of the following is the most appropriate reason for his bone marrow failure?
Your Answer: Acute viral infection
Correct Answer: Mercaptopurine toxicity
Explanation:The cause for bone marrow suppression in this patient is most probably mercaptopurine toxicity.Azathioprine is metabolized to 6-mercaptopurine (6-MP), which itself is metabolized by xanthine oxidase. Xanthine oxidase inhibition by allopurinol leads to the accumulation of 6-MP which then precipitates bone marrow failure. This may be potentially fatal if unrecognized.Clinical presentation:Toxicity symptoms include gastrointestinal symptoms, bradycardia, hepatotoxicity, myelosuppression.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 101
Incorrect
-
The cells that secrete HCL are found in which part of the stomach?
Your Answer: Antrum
Correct Answer: Body
Explanation:The stomach can be divided in to different regions. Cardia, fundus, body, antrum and pylorus from proximal end to distal end respectively. Different cell types are distributed accordingly among the regions of the stomach. Cells that secret HCl in the gastric mucosa are known as parietal cells and are abundant in the gastric body region. They have receptors for acetylcholine stimulated via the vagus nerve, histamine receptors and gastrin receptors which stimulate gastric acid secretion. G cells that secret gastrin are abundant in the antrum.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 102
Incorrect
-
Which of the following best describes the cardiac muscle?
Your Answer: Smooth and involuntary
Correct Answer: Striated and involuntary
Explanation:Cardiac muscle (heart muscle) is an involuntary, striated muscle that is found in the walls and histological foundation of the heart, specifically the myocardium. Cardiac muscle is one of three major types of muscle, the others being skeletal and smooth muscle.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 103
Correct
-
Translation usually begins at which codon?
Your Answer: AUG
Explanation:The start codon is the first codon of a messenger RNA (mRNA) transcript translated by a ribosome. The start codon always codes for methionine in eukaryotes and the most common start codon is AUG.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 104
Incorrect
-
What is a characteristic findings on ECG in hyperkalaemia?
Your Answer: Delta Waves
Correct Answer: Tall, tented T waves
Explanation:Hyperkalaemia leads to:
– Prolonged PR interval
– Small P waves
– Tall, tented T waves
– Widened QRS complexes and eventually asystole.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 105
Incorrect
-
Which two ducts form the ampulla of Vater?
Your Answer: The pancreatic duct of Wirsung and the duct of Santorini
Correct Answer: The common bile duct and the pancreatic duct of Wirsung
Explanation:The ampulla of Vater, also known as the hepatopancreatic ampulla or the hepatopancreatic duct, is formed by the union of the pancreatic duct and the common bile duct. The ampulla is specifically located at the major duodenal papilla.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 106
Incorrect
-
The pressure in the sinusoids is normally:
Your Answer: Higher than hepatic artery pressure
Correct Answer: Lower than portal venous pressure
Explanation:The direction of transport of nutrients in the portal vein occurs from the portal vein to the hepatic sinusoids. Thus, he pressure of sinusoids should be lower than the pressure of he portal vein.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
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Question 107
Correct
-
Embryologically the anterior pituitary is formed from?
Your Answer: Rathkes pouch
Explanation:The ectoderm, located in the roof of the pharynx, forms Rathke’s pouch, which comes into contact with the ectoderm of the developing brain. The pouch eventually separates from the pharynx, becoming the anterior pituitary.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 108
Incorrect
-
In the life cycle of plasmodium species:
Your Answer: Merozoites migrate to the salivary glands of the mosquito
Correct Answer: Merozoites are released from the liver and enter the red blood cell
Explanation:Plasmodium is a genus of parasitic protozoa, many of which cause malaria in their hosts. The parasite always has two hosts in its life cycle: a Dipteran insect host and a vertebrate host. Sexual reproduction always occurs in the insect, making it the definitive host.The life-cycles of Plasmodium species involve several different stages both in the insect and the vertebrate host. These stages include sporozoites, which are injected by the insect vector into the vertebrate host’s blood. Sporozoites infect the host liver, giving rise to merozoites and (in some species) hypnozoites. These move into the blood where they infect red blood cells. In the red blood cells, the parasites can either form more merozoites to infect more red blood cells, or produce gametocytes which are taken up by insects which feed on the vertebrate host. In the insect host, gametocytes merge to sexually reproduce. After sexual reproduction, parasites grow into new sporozoites, which move to the insect’s salivary glands, from which they can infect a vertebrate host bitten by the insect.
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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Question 109
Incorrect
-
Which of the following vitamin deficiencies is associated with xerophthalmia?
Your Answer: Vitamin D
Correct Answer: Vitamin A
Explanation:Xerophthalmia caused by a severe vitamin A deficiency is described by pathologic dryness of the conjunctiva and cornea. The conjunctiva becomes dry, thick and wrinkled. If untreated, it can lead to corneal ulceration and ultimately to blindness as a result of corneal damage.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 110
Incorrect
-
The intestine is lined by:
Your Answer: Stratified squamous epithelium
Correct Answer: Simple columnar epithelium
Explanation:In the small intestine, epithelium is simple columnar and specialised for absorption. The epithelium is arranged into villi, creating a brush border and increasing the area for absorption. The epithelium is simple columnar with microvilli.In the colon, epithelium is simple columnar and without villi. Goblet cells, which secrete mucous, are also present.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 111
Incorrect
-
A son has brought his 72-year-old mother to clinic. He is concerned about her short-term memory problems for the past 10 months. He has to remind her to take her medications and she has had two incidents of falling over in the last 10 months. Which of the following assists in the diagnosis of above condition?
Your Answer: Disinhibition
Correct Answer: Progressive loss of function
Explanation:The clinical presentation is dementia. To differentiate Alzheimer disease and vascular dementia, the progressive loss of function is important. Progressive loss of function is usually associated with vascular dementia and rest of the responses are associated with Alzheimer disease.
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This question is part of the following fields:
- Geriatrics
- Medicine
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Question 112
Correct
-
A 50-year-old male was under treatment for bipolar disease. He was brought to the emergency department as he had become increasingly confused over the past two days. He had vomiting and diarrhoea. He was also consuming and passing a lot of water.On examination, he was disoriented. He had vertical nystagmus and was ataxic.What two investigations are likely to lead to the correct diagnosis?
Your Answer: Desmopressin test and serum lithium level
Explanation:Desmopressin test (done to differentiate nephrogenic diabetes insipidus from central diabetes insipidus), and serum lithium levels can together confirm a diagnosis of lithium-induced nephrogenic diabetes insipidus.Bipolar disease is most often managed with mood stabilizers like lithium. This patient develops gastrointestinal symptoms followed by an acute confusional state associated with polyuria and polydipsia. These symptoms are suggestive of diabetes insipidus.In a case where these symptoms occur in a bipolar patient under treatment, lithium-induced nephrogenic diabetes insipidus should be considered as the most probable cause.Lithium intoxication can present with symptoms of nausea, vomiting, mental dullness, action tremor, weakness, ataxia, slurred speech, blurred vision, dizziness, especially vertical nystagmus and stupor or coma. Diffuse myoclonic twitching and nephrogenic diabetes insipidus can also occur. Such a clinical syndrome occurs above the serum level of lithium of 1.5–2.0 mEq/L.Management: – Correcting electrolyte abnormalities in patients with acute disease is critical and often life-saving.- Treatment should be initiated with parenteral fluids to replete hypovolemia (normal saline at 200-250 mL/h), followed by administration of hypotonic fluid (0.5% normal saline). – On the restoration of the volume status of the patient forced diuresis should be initiated by the administration of parenteral furosemide or bumetanide accompanied by continued intravenous hypotonic fluid administration to maintain volume status.- Polyuria is managed with hydrochlorothiazide combined with amiloride, acetazolamide.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 113
Incorrect
-
What is the most abundant cell type in the central nervous system called?
Your Answer: Neuron
Correct Answer: Astrocyte
Explanation:Astrocytes are the supporting cells of the central nervous system. There are two types; the fibrous type is found in the white matter and the protoplasmic type in the grey matter. They are the most abundant cell type in the CNS.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 114
Incorrect
-
The extrinsic coagulation pathway is initiated by activation of which clotting factor?
Your Answer: Factor II
Correct Answer: Factor VII
Explanation:The tissue factor pathway (extrinsic) begins following damage to the blood vessel. FVII leaves the circulation and comes into contact with tissue factor (TF) expressed on tissue-factor-bearing cells (stromal fibroblasts and leukocytes), forming an activated complex (TF-FVIIa).
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This question is part of the following fields:
- Haematology
- Medicine
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Question 115
Incorrect
-
The steps of cardiac cycle in sequence are:
Your Answer: Isovolumic contraction, isovolumic relaxation, ejection, passive ventricular filling, active ventricular filling.
Correct Answer: Isovolumic contraction, ejection, isovolumic relaxation, passive ventricular filling, active ventricular filling.
Explanation:The cardiac cycle refers to a complete heartbeat from its generation to the beginning of the next beat, and so includes the diastole, the systole, and the intervening pause.1st stage: diastole, or passive filling is when the semilunar valves (the pulmonary valve and the aortic valve) close, the atrioventricular (AV) valves (the mitral valve and the tricuspid valve) open, and the whole heart is relaxed. 2nd stage: atrial systole, is when the atrium contracts, and blood flows from atrium to the ventricle (active filling).3rd stage: isovolumic contraction is when the ventricles begin to contract, the AV and semilunar valves close, and there is no change in volume. 4th stage: ventricular ejection, is when the ventricles are contracting and emptying, and the semilunar valves are open. 5th stage: isovolumic relaxation time, pressure decreases, no blood enters the ventricles, the ventricles stop contracting and begin to relax, and the semilunar valves close due to the pressure of blood in the aorta.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 116
Incorrect
-
Which of the following is true for P53:
Your Answer: It binds e2f and stops the cell cycle at the g 1 phase
Correct Answer: It is induced by ‘broken’ DNA
Explanation:P53 gene is activated as a result of damaged DNA and if that cannot be repaired then it activates apoptosis.
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This question is part of the following fields:
- Genetics
- Medicine
-
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Question 117
Correct
-
Question 118
Incorrect
-
The only APCs that can activate naive T lymphocytes are:
Your Answer: Macrophages and monocytes
Correct Answer: Dendric cells
Explanation:Only professional antigen-presenting cells (macrophages, B lymphocytes, and dendritic cells) are able to activate a resting helper T-cell when the matching antigen is presented. However, macrophages and B cells can only activate memory T cells whereas dendritic cells can activate both memory and naive T cells, and are the most potent of all the antigen-presenting cells.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 119
Correct
-
The triangle with the heart at its centre, using limb leads is called:
Your Answer: Einthoven
Explanation:The Einthoven triangle is formed by placing the limb leads on both the arms and on the left leg with the heart in the centre.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 120
Incorrect
-
A 35-year-old man was brought to the ER with acute confusion. He's a known case of bipolar disorder under treatment with mood stabilizers. Blood investigations revealed lithium toxicity. A decision is made to start the patient on sodium bicarbonate. What is the rationale behind the use of sodium bicarbonate in this patient?
Your Answer: Myocardial stabiliser
Correct Answer: Increases urine alkalinity
Explanation:The rationale behind the use of sodium bicarbonate is that it increases the alkalinity of the urine promoting lithium excretion. The preferred treatment in severe cases would be haemodialysis.Lithium is a mood-stabilizing drug used most commonly prophylactically in bipolar disorder but also as an adjunct in refractory depression. It has a very narrow therapeutic range (0.4-1.0 mmol/L) and a long plasma half-life being excreted primarily by the kidneys. Lithium toxicity generally occurs following concentrations > 1.5 mmol/L.Toxicity may be precipitated by dehydration, renal failure, diuretics (especially Bendroflumethiazide), ACE inhibitors, NSAIDs and metronidazole.Features of toxicityCoarse tremor (a fine tremor is seen in therapeutic levels)HyperreflexiaAcute confusionSeizureComaManagementMild-moderate toxicity may respond to volume resuscitation with normal salineHaemodialysis may be needed in severe toxicitySodium bicarbonate is sometimes used but there is limited evidence to support this. By increasing the alkalinity of the urine it promotes lithium excretion.
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This question is part of the following fields:
- Medicine
- Pharmacology
-
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Question 121
Incorrect
-
A 30-year-old male is brought to the emergency department following his collapse in a night club. His friends who accompanied him admit that, of recent, he has been using increasing amounts of cocaine. Which among the following is commonly associated with cocaine overdose?
Your Answer: Hypothermia
Correct Answer: Metabolic acidosis
Explanation:Metabolic acidosis is associated with cocaine overdose. In overdose, cocaine leads to agitation, tachycardia, hypertension, sweating, hallucinations, and finally convulsions. Metabolic acidosis, hyperthermia, rhabdomyolysis, and ventricular arrhythmias also occur.Chronic use may be associated with premature coronary artery disease, dilated cardiomyopathy, and increased risk of cerebral haemorrhage.There are 3 stages for acute cocaine toxicity:Stage I: CNS symptoms of headache, vertigo, pseudo hallucinations, hyperthermia, hypertension. Stage II: increased deep tendon reflexes, tachypnoea, irregular breathing, hypertension.Stage III: Areflexia, coma, fixed and dilated pupils, hypotension, ventricular fibrillation, apnoea, and respiratory failure.Treatment:- Airway, breathing, and circulation to be secured. The patient’s fever should be managed, and one should rule out hypoglycaemia as a cause of the neuropsychiatric symptoms. – Cardiovascular toxicity and agitation are best-treated first-line with benzodiazepines to decrease CNS sympathetic outflow.- The mixed beta/alpha blocker labetalol is safe and effective for treating concomitant cocaine-induced hypertension and tachycardia.- Non-dihydropyridine calcium channels blockers such as diltiazem and verapamil have been shown to reduce hypertension reliably, but not tachycardia. – Dihydropyridine agents such as nifedipine should be avoided, as reflex tachycardia may occur. – The alpha-blocker phentolamine has been recommended but only treats alpha-mediated hypertension and not tachycardia.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 122
Correct
-
Regarding the formation of CSF, which of the following is true?
Your Answer: Its composition resembles that of brain ECF
Explanation:In normal adults CSF volume is around 125ml to 150ml. Turnover of entire volume of cerebrospinal fluid a day is about 3 to 4 times a day. Composition of CSF is similar to that of plasma except that CSF is nearly protein-free compared with plasma and has a different electrolyte level. About 80% of CSF is produced by the choroid plexus. It is also produced by a single layer of column shaped ependymal cells. The composition and rate of CSF generation depends on several factors and is influenced by hormones and the content and pressure of blood and CSF.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 123
Incorrect
-
A 50-year-old male presents to the ER allegedly claiming that he consumed a bottle of antifreeze. Which of the following symptoms is least likely to be associated with this kind of poisoning?
Your Answer: Acute renal failure
Correct Answer: Hypertension
Explanation:Loss of vision after consumption of antifreeze is a characteristic presentation of methanol poisoning.
Pathophysiology of methanol toxicity: When ingested, methanol is absorbed rapidly via the gastrointestinal tract in less than 10 minutes. Methanol is not protein-bound and is absorbed directly into the total body water compartment. Metabolism occurs mainly in the liver through serial oxidation via alcohol dehydrogenase and aldehyde dehydrogenase but begins with alcohol dehydrogenase present in the gastric mucosa. Alcohol dehydrogenase oxidizes methanol to formaldehyde, and aldehyde dehydrogenase subsequently oxidizes formaldehyde to formic acid. Formic acid is the primary toxic metabolite that accounts for the associated anion gap metabolic acidosis and end-organ damage.
Clinical presentation: Patients who present within the first 12 to 24 hours following ingestion may appear normal, and this is described as the latent period. Nausea, vomiting, and abdominal pain subsequently ensue, followed by CNS depression and hyperventilation due to metabolic acidosis. Ocular symptoms associated with retinal toxicity are often evident in the form of blurry vision, decreased visual acuity, photophobia, and “halo vision.”
Treatment: Treatment options for methanol toxicity include supportive care, fomepizole (Antizole, 4-Methylpyrazole or 4MP), ethanol, dialysis, and folate.
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This question is part of the following fields:
- Medicine
- Pharmacology
-
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Question 124
Incorrect
-
A 45 year old man presents with fever, malaise, weight loss and myalgias that have been occurring for a month. You suspect polyarteritis nodosa and arrange for some lab investigations. Which of the following abnormality would most likely be present?
Your Answer: Anaemia
Correct Answer: Elevated creatinine
Explanation:People with polyarteritis nodosa often exhibit anaemia of chronic disease. Leucocytosis and eosinophilia may also be present. ANCA is only rarely positive. As polyarteritis nodosa affects the kidneys as well, the creatinine is elevated in most cases.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 125
Incorrect
-
Café-au-lait spots are seen in each of the following, except:
Your Answer: Tuberous sclerosis
Correct Answer: Friedreich's ataxia
Explanation:Café-au-lait spots are hyperpigmented lesions that vary in colour from light brown to dark brown, with borders that may be smooth or irregular.
Causes include:
- Neurofibromatosis type I
- McCune–Albright syndrome
- Legius syndrome
- Tuberous sclerosis
- Fanconi anaemia
- Idiopathic
- Ataxia-telangiectasia
- Basal cell nevus syndrome
- Benign congenital skin lesion
- Bloom syndrome
- Chediak-Higashi syndrome
- Congenital nevus
- Gaucher disease
- Hunter syndrome
- Maffucci syndrome
- Multiple mucosal neuroma syndrome
- Noonan syndrome
- Pulmonary Stenosis
- Silver–Russell syndrome
- Watson syndrome
- Wiskott–Aldrich syndrome
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This question is part of the following fields:
- Dermatology
- Medicine
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Question 126
Incorrect
-
The following cells replicate without shortening their telomeres because they express telomerase.
Your Answer: Red blood cells
Correct Answer: Germ cells
Explanation:Telomerase activity is seen in germ cells and is absent in somatic cells. Telomeres prevent the chromosomes from shortening and prevent the coding portion of the DNA from being lost, thus allowing the cell to replicate indefinitely. During replication telomeres may be lost resulting in cell death.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 127
Incorrect
-
Critical shortening of Telomeres result in:
Your Answer: None of the above
Correct Answer: Activation of p53 and prb and cell crisis
Explanation:Telomeres are repetitive nucleotide sequences at the ends of chromosomes that protect them from deterioration or from fusion with neighboring chromosomes. Each time a cell divides, its telomeres shorten. When they become critically short, they can no longer protect the chromosome ends, triggering a DNA damage response.
This response leads to the activation of tumor suppressor proteins p53 and pRb (retinoblastoma protein). Activated p53 can induce cell cycle arrest, allowing time for DNA repair or triggering apoptosis if the damage is irreparable. Similarly, pRb helps regulate cell cycle progression and can halt the cell cycle to prevent the proliferation of cells with damaged DNA.
As a result, the cell enters a state of crisis, characterized by widespread cell death and genomic instability, which ultimately prevents the propagation of cells with critically shortened telomeres.
Therefore, the correct answer is:
Activation of p53 and pRb and cell crisis
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This question is part of the following fields:
- Genetics
- Medicine
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Question 128
Incorrect
-
When the heart rate is increased (to pathological levels) which of the following is correct when comparing the duration of diastole to systole?
Your Answer: It is equal to systole
Correct Answer: It is shortened to a greater degree
Explanation:The duration of systole is more fixed than the duration of diastole. When the heart rate increases the timing of the systole remains more or less the same however diastole decreases.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 129
Incorrect
-
Which of the following enzymes is mainly responsible for the hydrolysis of polysaccharide 1:6a linkages?
Your Answer: Maltase
Correct Answer: Isomaltase
Explanation:Isomaltase is mainly responsible for hydrolysis of 1:6α linkages. Along with maltase and sucrase, it also breaks down maltotriose and maltose.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 130
Correct
-
Increase Gamma motor neuron activity produces what effect on the muscle spindle sensitivity?
Your Answer: Increase
Explanation:The muscle spindle is supplied by both sensory and motor nerves. Sensory supply is Type Ia fibers whereas motor supply is via gamma motor neurons. These neurons also play a role in adjusting the sensitivity of muscle spindles. Increased neuron activity increases the muscle spindle sensitivity.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 131
Incorrect
-
Question 132
Incorrect
-
The following contributes to the rate of depolarization?
Your Answer: Stretch
Correct Answer: All of the options given
Explanation:Depolarization occurs due to impulses generated by the SA node. As the heart beats to the rhythm of the SA node, certain factors will effect the rate of depolarization. All the mentioned options effect the rate of depolarization.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 133
Correct
-
Neurogenesis occurs throughout life in the following two areas:
Your Answer: Hippocampus and striatum
Explanation:In humans, neurogenesis or new neurons are continually born during adulthood in two regions of the brain: The subgranular zone (SGZ), part of the dentate gyrus of the hippocampus and the striatum. In other species of mammals, adult-born neurons also appear in the olfactory bulb. In humans, however, few if any olfactory bulb neurons are generated after birth.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 134
Correct
-
A 22-year-old university student is admitted after taking drugs at a night club. Which of the following features suggest she had taken ecstasy (MDMA)?
Your Answer: A pyrexia of 40°C
Explanation:MDMA commonly known as ecstasy or molly, is a psychoactive drug primarily used as a recreational drug. The desired effects include altered sensations, increased energy, empathy, and pleasure. Features of MDMA abuse include hyponatraemia, tachycardia, hyperventilation, and hyperthermia.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 135
Incorrect
-
Which of the following enzymes are involved in Phase I drug metabolism?
Your Answer: N-acetyl transferases
Correct Answer: Alcohol dehydrogenase
Explanation:Drug metabolism can be broadly classified into:Phase I (functionalization) reactions: also termed non-synthetic reactions, they include oxidation, reduction, hydrolysis, cyclization and de-cyclization. The most common and vital reactions are oxidation reactions. (Of the given enzymes only Alcohol dehydrogenase is involved in phase I drug metabolism. Succinate dehydrogenase, is a vital enzyme involved in the Kreb’s cycle and the mitochondrial electron transport chain). They are mainly catalysed by Cytochrome P-450 enzyme.Phase II (conjugation) reactions: occur following phase I reactions, they include reactions: glucuronidation and sulphate conjugation, etc. They are mostly catalysed by UDP-glucuronosyltransferase enzyme. Other phase II enzymes include: sulfotransferases, N-acetyltransferases, glutathione S-transferases and methyltransferases.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 136
Incorrect
-
Regarding the myofilament molecules, which of the following contains binding sites for calcium that helps to initiate contraction?
Your Answer: Troponin t
Correct Answer: Troponin c
Explanation:Troponin T binds the troponin components to tropomyosin. Troponin I inhibits the interaction of myosin with actin and troponin C contains the binding sites for the Ca2+ that helps initiate contraction.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 137
Incorrect
-
An 82 year old male woke up experiencing incoherent speech - he is also finding it difficult to find the right words to explain his thoughts. Doctors have examined him, and everything else appears to be normal. They have also found that his comprehension is good. From the list of options, choose the anatomical site which in this instance, is most likely affected.
Your Answer: Parietal Cortex
Correct Answer: Broca’s Area
Explanation:The combination of good comprehension but poor speech quality in this patient is consistent with damage to the Broca’s area. The Wernicke’s area is responsible for the understanding of speech, and so is not consistent with this patient.
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This question is part of the following fields:
- Geriatrics
- Medicine
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Question 138
Incorrect
-
Which cranial nerve is responsible for the parasympathetic nerve supply of the thorax and upper abdomen?
Your Answer: CN lX
Correct Answer: CN X
Explanation:Cranial nerve X supplies the structures of the thorax and abdomen. All the rest of the cranial nerves supply the structures in the head and neck
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This question is part of the following fields:
- Medicine
- Neurology
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Question 139
Incorrect
-
Where is the most erythropoietin produced?
Your Answer: Bone marrow
Correct Answer: Kidneys
Explanation:Erythropoietin is produced by interstitial fibroblasts in the kidney in close association with peritubular capillary and proximal convoluted tubule. It is also produced in perisinusoidal cells in the liver. While liver production predominates in the fetal and perinatal period, renal production is predominant during adulthood.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 140
Incorrect
-
Mutation in RB can lead to the formation of which cancer?
Your Answer: Colorectal carcinoma
Correct Answer: Retinoblastoma
Explanation:Patients with a history of autosomal dominant familial retinoblastoma have at least one mutated copy of the RB gene. This predisposes the patient to develop retinoblastoma in one or both the eyes. Patients with a family history should be screened properly so that it can be detected and treated as early as possible.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 141
Incorrect
-
Question 142
Incorrect
-
Which of the following would provide relief from nausea and vomiting?
Your Answer: SSRI’s
Correct Answer: Cannabinoids
Explanation:Ondansetron, chlorpromazine and haloperidol are effective antiemetic agents. Corticosteroids, cannabinoids, and benzodiazepines, alone or in combination with 5-HT3 and D2 antagonists, are also useful in the treatment of vomiting produced by chemotherapy.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 143
Incorrect
-
Which of the following corresponds to an oblique line drawn from the sternal end of the left 3rd costal cartilage to the sternal end of the right 6th costal cartilage?
Your Answer: Aortic arch
Correct Answer: Atrio-ventricular (coronary) groove
Explanation:The AV groove corresponds to the right border of the heart. The right border corresponds to a line drawn from the 3rd right costal cartilage to the 6th right costal cartilage; this border is slightly convex to the right.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 144
Correct
-
Which one of the following makes up most of the adrenal cortex?
Your Answer: Zona fasciculata
Explanation:The zona fasciculata represents the widest area of the adrenal cortex, situated in the middle of the cortex. It produces glucocorticoids including; 11-deoxycorticosterone, corticosterone, and cortisol.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 145
Incorrect
-
Which of the following derivatives of proopiomelanocortin is an opioid peptide?
Your Answer: ACTH
Correct Answer: ß-endorphin
Explanation:ß-endorphin is an endogenous opioid neuropeptide which is mainly synthesized and stored in the anterior pituitary gland, derived from the precursor proopiomelanocortin (POMC). Some studies have shown that immune system cells are also capable of synthesizing ß-endorphin. β-endorphin is thought to exert a tonic inhibitory influence upon GNRH secretion and to be an important regulator of reproductive function.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 146
Correct
-
A 40-year-old man is admitted to the Emergency Department in a confused state. He tells you that he consumed two bottles of antifreeze. On examination, his pulse is 120 bpm and blood pressure is 140/90 mmHg. An arterial blood gas analysis shows uncompensated metabolic acidosis. He is transferred to the high dependency unit and ethanol is given via a nasogastric tube. How does ethanol help this patient?
Your Answer: Competes with ethylene glycol for alcohol dehydrogenase
Explanation:Ethanol competes with ethylene glycol for alcohol dehydrogenase and thus, helps manage a patient with ethylene glycol toxicity.Ethylene glycol is a type of alcohol used as a coolant or antifreezeFeatures of toxicity are divided into 3 stages:Stage 1: (30 min to 12 hours after exposure) Symptoms similar to alcohol intoxication: confusion, slurred speech, dizziness (CNS depression)Stage 2: (12 – 48 hours after exposure) Metabolic acidosis with a high anion gap and high osmolar gap. Also tachycardia, hypertensionStage 3: (24 – 72 hours after exposure) Acute renal failureManagement has changed in recent times:Fomepizole, an inhibitor of alcohol dehydrogenase, is now used first-line in preference to ethanol.Ethanol has been used for many years works by competing with ethylene glycol for the enzyme alcohol dehydrogenase this limits the formation of toxic metabolites (e.g. glycolaldehyde and glycolic acid) which are responsible for the hemodynamic/metabolic features of poisoning.Haemodialysis has a role in refractory cases.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 147
Incorrect
-
Bone marrow barrier is important to:
Your Answer: Prevent bacteria entering the bone marrow
Correct Answer: Allow mature red blood cells to pass into circulation
Explanation:The blood vessels of the bone marrow constitute a barrier, inhibiting immature blood cells from leaving the marrow. Only mature blood cells contain the membrane proteins, such as aquaporin and glycophorin, that are required to attach to and pass the blood vessel endothelium.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 148
Incorrect
-
What is the effect of vasopressin on the kidney?
Your Answer: Decrease the glomerulus filtration rate
Correct Answer: Increase collecting duct permeability to water
Explanation:Vasopressin, also known as antidiuretic hormone or ADH, which increases water reabsorption in the kidney’s collecting ducts. It works by increasing water permeability in the collecting ducts and distal convoluted tubules. It induces the exocytosis of AQP-CD-laden vesicles, transferring water channels from intracellular vesicles to the apical plasma membrane, therefore allowing more water to be reabsorbed from the urine in the collecting ducts to the blood.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 149
Incorrect
-
ADH causes?
Your Answer: Decreased permeability of the collecting ducts to water
Correct Answer: Increased permeability of the collecting ducts to water
Explanation:Vasopressin (ADH) has three main effects:1. Increasing the water permeability of distal convoluted tubule and collecting duct cells in the kidney, thus allowing water reabsorption and excretion of more concentrated urine.2. Increasing permeability of the inner medullary portion of the collecting duct to urea by regulating the cell surface expression of urea transporters.3. Acute increase of sodium absorption across the ascending loop of Henle.
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This question is part of the following fields:
- Medicine
- Renal
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Question 150
Incorrect
-
The majority of corticospinal tract fibers decussate in the:
Your Answer: Midbrain
Correct Answer: Medulla
Explanation:The corticospinal tract is a descending motor path way that begins in the cerebral cortex and decussates in the pyramids of the medulla.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 151
Incorrect
-
Which of the following drug can cause galactorrhoea?
Your Answer: Lisinopril
Correct Answer: Metoclopramide
Explanation:Metoclopramide causes extrapyramidal effects (especially in children and young adults), hyperprolactinaemia, and occasionally tardive dyskinesia on prolonged administration. Also reported are drowsiness, restlessness, diarrhoea, depression, neuroleptic malignant syndrome, rashes, pruritus, oedema.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 152
Incorrect
-
Treatment of an acute attack of gout with allopurinol may result in which of the following?
Your Answer: Acute pyelonephritis
Correct Answer: Exacerbation and prolongation of the attack
Explanation:Initiation of allopurinol treatment during an attack can exacerbate and prolong the episode. Thus treatment should be delayed until the attack resolves.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 153
Incorrect
-
Which of the following is not true regarding mitochondrial chromosome disorders?
Your Answer: Mitochondrial chromosome defects are inherited from one’s mother
Correct Answer: Because mitochondrial chromosomes have no introns in their genes, any point mutation has a low likelihood of having an effect.
Explanation:Any point mutation in any part of the mitochondrial DNA will lead to a mutated mitochondria and will likewise have its ill effect on the body.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 154
Incorrect
-
A 23-year-old female known with schizophrenia is being reviewed in the emergency department. Her mother claims that she has been 'staring' for the past few hours but has now developed abnormal head movements and has gone 'cross-eyed'. On examination, the patient's neck is extended and positioned to the right. Her eyes are deviated upwards and are slightly converged. Given the likely diagnosis, what is the most appropriate treatment?
Your Answer: Haloperidol
Correct Answer: Procyclidine
Explanation:The most probable diagnosis in this patient is an oculogyric crisis, that is most appropriately managed with procyclidine or benztropine (antimuscarinic). An oculogyric crisis is a dystonic reaction to certain drugs or medical conditions.Features include:Restlessness, agitationInvoluntary upward deviation of the eyesCauses:PhenothiazinesHaloperidolMetoclopramidePostencephalitic Parkinson’s diseaseManagement:Intravenous antimuscarinic agents like benztropine or procyclidine, alternatively diphenhydramine or ethopropazine maybe used.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 155
Incorrect
-
Question 156
Incorrect
-
Which enzyme facilitates the function of pancreatic lipase by increasing exposure of its active site?
Your Answer: Pancreatic amylase
Correct Answer: Colipase
Explanation:Colipase is a co enzyme that optimize the activity of lipase by facilitating the exposure of its active sites.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 157
Incorrect
-
In increasing order of concentration, the main anions in plasma are:
Your Answer: SO42-, Phosphates-, HCO3-, Cl-
Correct Answer: Proteins-, HCO3-, Cl-,
Explanation:Anions are negatively charged ions and include: chloride Cl-, bicarbonate HCO3-, sulphate SO4-2, phosphate HPO4-2, and protein anions. Chloride it the most abundant anion followed by bicarbonate and then protein anions.
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This question is part of the following fields:
- Medicine
- Renal
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Question 158
Incorrect
-
Absorption of protein antigens i.e. bacterial and viral proteins takes place in the:
Your Answer: Mucosa-associated lymphoid tissue
Correct Answer: Microfold cells (m cells) of the intestine
Explanation:M cells are specialized epithelial cells. They have a high capacity of transcytosis of microorganisms and macromolecules. They rapidly uptake antigens and present them to immune cells associated with the gut. In contrast to absorptive enterocytes, M cells do not exert direct defence mechanisms to antigens and pathogens in the intestinal cavity. Crypts of Lieberkühn are located mainly in the small intestine and large intestine and the main function is to replenish epithelial cells and to secrete intestinal enzymatic juice as well as mucous. Brunner’s glands empty into intestinal glands and their main function is to secrete mucin and to form a protective mucus layer on the duodenal epithelial cells to protect it from acidic chyme coming from the stomach. Islets of Langerhans are located in the pancreas and secrets insulin mainly. Mucosa associated lymphoid tissue plays a role in inducing immune response after presentation of antigens.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 159
Incorrect
-
During which phase of meiosis does exchange of genetic material occur accounting for genetic diversity between individuals:
Your Answer: Telophase 2
Correct Answer: Prophase 1
Explanation:Prophase 1 has been divided into five different stages ( laptotene, zygotene, pachytene, diplotene ans diakinesis). In prophase 1 chromosomes are going to condense to become visible, each chromosome will contain two chromatids that are joined at the centromere. the nucleolus and nuclear envelope are going to disintegrate. the homologous chromosomes will form tetrad and crossing over will occur between the chromosomes (random exchange of genes), the point of exchange is known as the chiasmata, this increases genetic diversity.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 160
Incorrect
-
During which stage of sleep is muscle tone in the limbs most reduced?
Your Answer: Stage 2
Correct Answer: REM
Explanation:Rapid eye movement (REM) stage is marked by extensive physiological changes in the body, such as accelerated respiration, increased brain activity and muscle relaxation. People dream during REM sleep, perhaps as a result of excited brain activity and the paralysis of major voluntary muscles.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 161
Incorrect
-
Activation of nitric oxide synthesis by endothelial cells is triggered by:
Your Answer: Acetylcholine
Correct Answer: All of the above
Explanation:Acetylcholine, histamine, bradykinin, vasoactive intestinal peptide (VIP) and shear stress on the endothelial cells causing the release of NO. NO is formed from arginine and causes vasodilatation of the blood vessels.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 162
Incorrect
-
Which heart sounds are matched correctly?
Your Answer: S1 - closure of AV valves
Correct Answer: All of the above
Explanation:In healthy adults, there are two normal heart sounds often described as a lub and a dub (or dup), that occur in sequence with each heartbeat. These are the first heart sound (S1) and second heart sound (S2), produced by the closing of the atrioventricular valves and semilunar valves, respectively. In addition to these normal sounds, a variety of other sounds may be present including heart murmurs, adventitious sounds, and gallop rhythms S3 and S4. S3 is thought to be caused by the oscillation of blood back and forth between the walls of the ventricles initiated by blood rushing in from the atria. The reason the third heart sound does not occur until the middle third of diastole is probably that during the early part of diastole, the ventricles are not filled sufficiently to create enough tension for reverberation. S4 when audible in an adult is called a presystolic gallop or atrial gallop. This gallop is produced by the sound of blood being forced into a stiff or hypertrophic ventricle.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 163
Incorrect
-
In Jugular vein pressure the “a” wave represents?
Your Answer: None of above
Correct Answer: Atrial systole
Explanation:The jugular venous pressure (JVP, sometimes referred to as jugular venous pulse) is the indirectly observed pressure over the venous system via visualization of the internal jugular vein. It can be useful in the differentiation of different forms of heart and lung disease. Classically three upward deflections and two downward deflections have been described: The upward deflections are the a (atrial contraction), c (ventricular contraction and resulting bulging of tricuspid into the right atrium during isovolumetric systole) and v = venous filling.The downward deflections of the wave are the x (the atrium relaxes and the tricuspid valve moves downward) and the y descent (filling of ventricle after tricuspid opening).
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 164
Correct
-
Select the correct pairing regarding the surface of the cerebral hemispheres.
Your Answer: Parietal lobe : primary somatosensory cortex
Explanation:Parietal lobe: The primary somatosensory cortex is located in the postcentral gyrus of the parietal lobe. It is responsible for processing sensory information from the body.
Frontal lobe: The primary motor cortex is located in the precentral gyrus of the frontal lobe. The frontal lobe also contains the premotor cortex, which is involved in planning movements. The primary visual cortex is located in the occipital lobe, not the frontal lobe.
Temporal lobe: The primary auditory cortex is located in the superior temporal gyrus of the temporal lobe. The primary motor and premotor cortices are located in the frontal lobe, not the temporal lobe.
Occipital lobe: The primary visual cortex is located in the occipital lobe. The primary auditory cortex is located in the temporal lobe, not the occipital lobe.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 165
Incorrect
-
The complete oxidation of 1 molecule of glucose to CO2 and H20 produces a total of __ATP.
Your Answer: 16
Correct Answer: 38
Explanation:Textbooks often state that 38 ATP molecules can be made per oxidised glucose molecule during cellular respiration (2 from glycolysis, 2 from the Krebs cycle, and about 34 from the electron transport system). However, this maximum yield is never quite reached because of losses due to leaky membranes as well as the cost of moving pyruvate and ADP into the mitochondrial matrix, and current estimates range around 29 to 30 ATP per glucose.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 166
Incorrect
-
A 71-year-old woman residing in a nursing home for a couple of years complains of drooling of saliva and sudden difficulty in swallowing while eating. She is a known hypertensive on treatment. What would be your next step?
Your Answer: Laryngoscopy
Correct Answer: Endoscopy
Explanation:Dysphagia or difficulty in swallowing. Endoscopy allows for visual examination of the oesophagus and is indicated in patients with dysphagia to determine the underlying aetiology, exclude malignant and premalignant conditions, assess the need for therapy, and perform therapy including dilation.
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This question is part of the following fields:
- Geriatrics
- Medicine
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Question 167
Incorrect
-
Pepsinogens are inactive pepsin precursors which are activated by
Your Answer: Bile acids
Correct Answer: Gastric acid
Explanation:Pepsinogen is converted to pepsin by the action of hydrochloric acid i.e. gastric acid
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 168
Incorrect
-
Hyperkalaemia [K+ =7meq/l] can lead to the following ECG changes [Ca++ normal]
Your Answer: QRS lengthened
Correct Answer: Peaked T waves
Explanation:Hyperkalaemia causes the formation of tall tented T waves due to altered repolarization.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 169
Incorrect
-
The growth promoting protein anabolic effects of insulin are mediated by:
Your Answer: Igf-1
Correct Answer: Phosphatidylinositol 3-kinase
Explanation:Phosphatidylinositol 3-kinase or PI-3Ks are a group of enzymes which are involved in a number of different cellular functions. PI-3Ks interact with insulin and the insulin receptor substrate, regulating glucose uptake. They are an important element in the insulin signalling pathway.
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This question is part of the following fields:
- Endocrinology
- Medicine
-
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Question 170
Incorrect
-
An 18 year old boy, thin with a tall stature, and a high arched palate arrives at the hospital with a spontaneous pneumothorax. He is accompanied by his brother who has a similar appearance. You suspect Marfan's Syndrome. The gene encoding which of the following proteins is defective in this condition?
Your Answer: Collagen
Correct Answer: Fibrillin-1
Explanation:A variety of proteins compose the structure of microfibrils, the most prominent of which are the two fibrillins. Fibrillin-1 a scaffolding protein is encoded by FBN1 on human chromosome 15q21 and fibrillin-2 is encoded by FBN2 on 5q23. Mutations in FBN1 produce Marfan syndrome, a pleiotropic autosomal dominant connective tissue disorder with prominent manifestations in the skeleton, eye and cardiovascular system. A number of conditions related to Marfan syndrome are also due to FBN1 mutations.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 171
Incorrect
-
Almost all of the protein that appears in the stool is:
Your Answer: Of dietary origin
Correct Answer: Comes from bacteria and cellular debris
Explanation:75% of faecal weight is water. By dry weight 30% of faeces is bacteria,10-20% is fat and 2-3% proteins. Almost all proteins ingested are absorbed in the gut.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 172
Incorrect
-
During which phase of the cardiac cycle does most of the ventricular filling occur?
Your Answer: Isovolumetric ventricular relaxation
Correct Answer: Ventricular diastole
Explanation:During the phase of ventricular diastole when the heart muscle relaxes and all the valves are open, blood flows easily into the heart. This is the phase of rapid ventricular filling. During isovolumetric contraction and relaxation the volume of blood in the heart does not change. During ventricular ejection blood enters into the aorta and pulmonary vessels.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 173
Incorrect
-
Which of the following conditions is least likely to exhibit the Koebner phenomenon?
Your Answer: Molluscum contagiosum
Correct Answer: Lupus vulgaris
Explanation:The Koebner phenomenon refers to skin lesions appearing on lines of trauma, exposure to a causative agents including: molluscum contagiosum, warts and toxicodendron dermatitis or secondary to scratching rather than an infective or chemical cause include vitiligo, psoriasis, lichen planus, lichen nitidus, pityriasis rubra pilaris, and keratosis follicularis (Darier disease).
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This question is part of the following fields:
- Dermatology
- Medicine
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Question 174
Incorrect
-
What is the isolated effect of B2 stimulation on the coronaries?
Your Answer: Vasoconstriction
Correct Answer: Vasodilatation
Explanation:Norepinephrine and epinephrine are agonists for all adrenergic receptor subtypes, although with varying affinities. Based on their physiology and pharmacology, adrenergic receptors have been divided into two principal types: alpha and beta. These types have been further differentiated into alpha-1, alpha-2, b1, and b2 receptors.
Alpha-1 Receptors are located on postsynaptic cells in smooth muscle and elicit vasoconstriction.
Alpha-2 receptors are localized on presynaptic membranes of postganglionic nerve terminals that synthesize norepinephrine. When activated by catecholamines, alpha-2 receptors act as negative feedback controllers, inhibiting further norepinephrine release.
Activation of myocardial b1 receptors stimulates the rate and strength of cardiac contraction, and consequently increases cardiac output. b1 Receptor activation also stimulates renin release from the kidney. Another class of antihypertensive agents acts by inhibiting b1 receptors.
Activation of b2 receptors by epinephrine relaxes vascular smooth muscle and results in vasodilation.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 175
Incorrect
-
Restriction Enzymes...
Your Answer: Cut mitochondrial sequences at specific sites
Correct Answer: Cut DNA sequences at specific sites
Explanation:Restriction endonucleases are enzymes that recognise short sequences of double stranded DNA and cut them at specific nucleotide points or sequences. These sequences differ for different restriction endonucleases.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 176
Incorrect
-
Which cells secrete insulin?
Your Answer: A cells of the islets of Langerhans
Correct Answer: B cells of the pancreatic islets
Explanation:Insulin is synthesised and stored by the B cells of the pancreatic islets (70% of islet cells), glucagon is synthesised and stored in the A cells (20%) and somatostatin is synthesised and stored in the D cells (10%).
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This question is part of the following fields:
- Endocrinology
- Medicine
-
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Question 177
Correct
-
A 42 year old male arrives at the clinic due to cough and haemoptysis. Examination shows nasal mucosal ulceration. The doctor suspects Wegener's granulomatosis. Which anatomical area would be most commonly involved in this condition?
Your Answer: Lungs
Explanation:Granulomatosis with polyangiitis (GPA, previously known as Wegener’s granulomatosis) is a systemic vasculitis that affects both small and medium-sized vessels. Patients typically initially suffer from a limited form that may consist of constitutional symptoms and localized manifestations such as chronic sinusitis, rhinitis, otitis media, ocular conditions. In later stages, more serious manifestations may arise, including pulmonary complications and glomerulonephritis, although the skin, eyes, and heart may also be involved but these lesions are less common. Diagnosis is based on laboratory testing (positive for PR3-ANCA/c-ANCA), imaging, and biopsy of affected organs, which demonstrate necrotizing granulomatous inflammation. GPA is treated with immunosuppressive drugs, typically consisting of glucocorticoids combined with methotrexate, cyclophosphamide, or rituximab. Relapses are common and the following systems are affected: Lower respiratory tract (95% of cases), renal involvement (80% of cases), skin lesions (45% of cases), ocular involvement (45% of cases) and cardiac involvement (33% of cases).
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 178
Incorrect
-
A study is carried out to assess the efficacy of a new anti-epileptic drug for children with absence seizures. The total number of the children selected for the study was 400, from which 150 children were assigned to take the new drug and 250 children were assigned in the control group. After a period of four months, only 15 children taking the new drug had a seizure compared to 100 children from the control group who had seizure. What is the correct value regarding the relative risk reduction?
Your Answer: 30%
Correct Answer: 75%
Explanation:Relative risk reduction (RRR) tells you by how much the treatment reduced the risk of bad outcomes relative to the control group who did not have the treatment. In the previous example, the relative risk reduction of fever and rash in the group of the children on the intervention was 40 per cent (1 – 0.6 = 0.4 or 40 per cent). RRR = (EER -CER) / CER = (0.1 – 0.4) / 0.4 = -0.75 or 75% reduction.
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This question is part of the following fields:
- Medicine
- Research Skills
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Question 179
Incorrect
-
Glucose transport in the brain is mediated by:
Your Answer: GLUT 3
Correct Answer: GLUT 1
Explanation:The facilitative glucose transporter mediates the transport of glucose from blood into neurons and glia in the brain. The primary isoforms in the brain are GLUT1 detected at high concentrations.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 180
Correct
-
Which of the following forms an important constituent of the brush border on the microvilli of the intestinal epithelium?
Your Answer: Hydrolases
Explanation:There are certain enzymes which are part of the brush border cells including hydrolases also known as the brush border hydrolases. They perform the final step in digestion of certain nutrients.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 181
Incorrect
-
A 50-year-old woman under treatment for manic-depressive psychosis presents in an unconscious state after an episode of seizure on the street. Her husband who accompanied her into the ER reported that they argued about 6-7 hours ago. On examination, she is found to be hypertonic with a GCS of 8, BP: 90/60 mmHg and a pulse of 105 bpm. Blood investigations revealed a lithium level of 3.2 mmol/L. She was intubated and ventilated. Which of the following is the most appropriate immediate management in this case?
Your Answer: Gastric lavage should be considered
Correct Answer: N saline should be started iv
Explanation:- Normal saline (N saline) should be started IV: Intravenous normal saline is recommended to enhance renal excretion of lithium. Adequate hydration is crucial because lithium is primarily excreted by the kidneys, and maintaining good urine output can help reduce lithium levels.
- Dialysis: This is considered the most effective treatment for severe lithium toxicity, especially when serum levels are significantly elevated (typically >2.5 mmol/L) and the patient presents with severe symptoms such as seizures, altered mental status, or renal impairment. Given the patient’s lithium level of 3.2 mmol/L and her critical condition, dialysis is necessary to rapidly reduce lithium levels.
The other options are less appropriate or ineffective in this context:
- Gastric lavage should be considered: This is not typically recommended for lithium poisoning because lithium is rapidly absorbed and lavage is unlikely to be effective several hours post-ingestion.
- Activated charcoal is likely to be effective: Activated charcoal does not effectively bind lithium and is not recommended for lithium poisoning.
- 5% dextrose should be started IV: While maintaining hydration is important, normal saline is preferred over dextrose solutions in this context to promote renal excretion of lithium.
- Dialysis is not normally required unless levels are above 5 mmol/L: This statement is incorrect. Dialysis is often required at lower levels, particularly in cases of severe toxicity or if the patient is symptomatic, as seen in this case.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 182
Incorrect
-
The enzyme that catalyses the final step in glycogen synthesis is:
Your Answer: Lipase
Correct Answer: Glycogen synthase
Explanation:Glycogen synthase is a key enzyme in glycogenesis, the conversion of glucose into glycogen. This enzyme combines excess glucose residues one by one into a polymeric chain for storage as glycogen.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 183
Incorrect
-
Stimulation of the carotid sinus results in:
Your Answer: Thirst
Correct Answer: Drop in blood pressure
Explanation:Stimulation of the carotid sinus will result in an increase in the baroreceptor discharge. This will travel via the afferent nerves to the medulla. Signals will pass through the vagus nerve to decrease the sympathetic outflow to the heart and the blood vessels. This inhibition will result in vasodilation of the blood vessels, venodilation and bradycardia hence decreasing the total peripheral resistance and lowering the blood pressure.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 184
Incorrect
-
B1 adrenergic stimulation produces:
Your Answer: Decrease in muscle contraction
Correct Answer: Increase in calcium cytosolic concentration
Explanation:Norepinephrine secreted by the sympathetic endings binds to B1 receptors, and the resulting increase in intracellular cAMP facilitates the opening of L channels, increasing Ica and the rapidity of the depolarization phase of the impulse and activates PKA which leads to phosphorylation of the voltage-gated Ca2+ channels, causing them to spend more time in the open state.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 185
Incorrect
-
Humoral immunity is a major defence against:
Your Answer: Bacterial infections
Correct Answer: Viral infections
Explanation:Humoral immunity is provided by the neutralizing and non-neutralizing antibodies that are formed from the B lymphocytes. This form of immunity is most important in viral infection. Non-neutralizing antibodies increases phagocytosis of the infected cell and inhibit the ability of the virus to replicate.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 186
Incorrect
-
von Willebrand factor stabilises which clotting factor?
Your Answer: Factor II
Correct Answer: Factor VIII
Explanation:Von Willebrand factor’s primary function is binding to other proteins, in particular factor VIII, and it is important in platelet adhesion to wound sites. It is not an enzyme and, thus, has no catalytic activity. Factor VIII degrades rapidly when not bound to vWF. Factor VIII is released from vWF by the action of thrombin.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 187
Correct
-
What is the most important way in which heat is lost from the body?
Your Answer: Radiation and conduction
Explanation:The body maintains a constant core temperature by balancing heat loss and heat gain. The mechanisms of heat loss are: radiation, evaporation, convection and conduction. Out of these mechanisms, the most important under normal conditions are radiation, through which body heat is given off to the surrounding atmosphere; and conduction, in which the body releases heat into the objects it comes into contact with.
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This question is part of the following fields:
- Endocrinology
- Medicine
-
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Question 188
Incorrect
-
Which enzyme hydrolyses triglycerides in lipoproteins into free fatty acids for storage in fat cells?
Your Answer: Hmg- coa reductase
Correct Answer: Lipoprotein lipase
Explanation:Lipoprotein lipase is a water-soluble enzyme that hydrolyses triglycerides in lipoproteins, such as those found in chylomicrons and very low-density lipoproteins (VLDL), into two free fatty acids and one monoacylglycerol molecule.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 189
Incorrect
-
Which mechanism of action does Penicillin use?
Your Answer: Inhibit DNA gyrase
Correct Answer: Inhibit cell wall synthesis
Explanation:Bacteria constantly remodel their peptidoglycan cell walls, simultaneously building and breaking down portions of the cell wall as they grow and divide. β-Lactam antibiotics inhibit the formation of peptidoglycan cross-links in the bacterial cell wall; this is achieved through binding of the four-membered β-lactam ring of penicillin to the enzyme DD-transpeptidase. As a consequence, DD-transpeptidase cannot catalyse formation of these cross-links, and an imbalance between cell wall production and degradation develops, causing the cell to rapidly die.
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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Question 190
Incorrect
-
Which vagus nerve mainly supplies the AV node?
Your Answer: Both left and right vagus
Correct Answer: Left vagus
Explanation:As the AV node develops from the left side of the embryo It is supplied by the left vagus nerve.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 191
Correct
-
What catalyses the conversion of adenosine to inosine?
Your Answer: Adenosine deaminase
Explanation:Adenosine deaminase (ADA) is an enzyme involved in purine metabolism. It is needed for the breakdown of adenosine from food and for the turnover of nucleic acids in tissues. ADA irreversibly deaminates adenosine, converting it to the related nucleoside inosine by the substitution of the amino group for a keto group.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 192
Correct
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The V wave in the jugular pulse is caused by:
Your Answer: Atrial filling
Explanation:The v wave reflects the passive increase in pressure and volume of the right atrium as it fills in late systole and early diastole.
The jugular vein pulsations usually have two elevations and two troughs. The first elevation (a wave) corresponds to the slight rise in atrial pressure resulting from atrial contraction. The first descent (x descent) reflects a fall in atrial pressure that starts with atrial relaxation. The second elevation (v wave) corresponds to ventricular systole when blood is entering the right atrium from the vena cavae while the tricuspid valve is closed. Finally, the second descent (y descent) reflects falling right atrial pressure as the tricuspid valve opens and blood drains from the atrium into the ventricle.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 193
Incorrect
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The hepatic plates in the liver parenchyma consist of how many cell layers?
Your Answer: More than a hundred cell layers
Correct Answer: 1 – 2 cell layers
Explanation:Hepatic plates in a hepatic lobule are arranged in 1-2 cell layers.
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This question is part of the following fields:
- Hepatobiliary
- Medicine
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Question 194
Correct
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Select one true statement about haemoglobin synthesis…
Your Answer: Occurs in the cytosol of developing red cells.
Explanation:Haemoglobin (Hb) is synthesized in a complex series of steps. The haem part is synthesized in a series of steps in the mitochondria and the cytosol of immature red blood cells, while the globin protein parts are synthesized by ribosomes in the cytosol. Production of Hb continues in the cell throughout its early development from the proerythroblast to the reticulocyte in the bone marrow.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 195
Incorrect
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A 56-year-old male presents to the emergency department with confusion and agitation for the past four hours. He is a known alcoholic who has abstained from drinking for the past three days.On examination, he is sweating, agitated and disorientated. His temperature is 37.7°C, pulse 112 bpm regular and blood pressure is 150/76 mmHg. Blood investigations performed in the emergency department reveal:FBC: NormalU&E: NormalPlasma glucose: 4.6 mmol/l (3.6-6)Which of the following medications would be the most appropriate treatment for this man?
Your Answer: Oral diazepam
Correct Answer: Oral lorazepam
Explanation:The most probable diagnosis for this patient is delirium tremens due to alcohol withdrawal, which should be treated as a medical emergency. Delirium tremens is a hyperadrenergic state and is often associated with tachycardia, hyperthermia, hypertension, tachypnoea, tremor, and mydriasis.Treatment:- The most common and validated treatment for alcohol withdrawal is benzodiazepine: first-line treatment includes oral lorazepam. – If the symptoms persist, or the medication is refused, parenteral lorazepam, haloperidol or olanzapine should be given.- Central-acting, alpha-2 agonists such as clonidine and dexmedetomidine should not be used alone for the treatment of alcohol withdrawal.- It is also recommended to avoid using alcohol, antipsychotics, anticonvulsants, beta-adrenergic receptor blockers, and baclofen for the treatment of alcohol withdrawal as there are not enough studies to support the safety of these.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 196
Incorrect
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After exercise, O2 debt repay may take up to:
Your Answer: 3 days
Correct Answer: 90 min
Explanation:Physical activity or exercise requires oxygen for production of ATP or energy via aerobic pathways of energy production. When the amount of oxygen that reaches muscles depletes, cells start producing energy anaerobically by partial breakdown of glucose resulting in lactic acid. Lactic acid should be removed from cells as it causes muscle fatigue. Oxygen is needed to oxidize lactic acid in to carbon dioxide and water and this need is known as oxygen debt. The existence of an oxygen debt explains why we continue to breathe deeply and quickly for a while after exercise. This may take up from 60 – 90 mins.
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This question is part of the following fields:
- Medicine
- Respiratory
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Question 197
Incorrect
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To which protein is T3 mostly bound in the serum?
Your Answer:
Correct Answer: Thyroxin-binding globulin
Explanation:In a normal person, approximately 0.03 per cent of the total serum T4, and 0.3 per cent of the total serum T3 are present in free or unbound form. The major serum thyroid hormone-binding proteins are: 1) thyroxine-binding globulin [TBG or thyropexin], 2) transthyretin [TTR or thyroxine-binding prealbumin (TBPA)], and 3) albumin (HAS, human serum albumin). TBG has highest affinity for T4, which is 50-fold higher than that of TTR and 7,000-fold higher that of HSA. As a result TBG binds 75% of serum T4, while TTR and HSA binds only 20% and Albumin 5%, respectively.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 198
Incorrect
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A 25-year-old woman presented to the ED with carbon monoxide poisoning. High-flow oxygen was administered immediately. She had a GCS of 15 and her vitals were stable. Which one of the following is not an indication for hyperbaric oxygen therapy in this scenario?
Your Answer:
Correct Answer: A carboxyhaemoglobin concentration of 16%
Explanation:Carbon monoxide (CO) poisoning, considered as the great imitator of other diseases, as the patients present with a myriad of symptoms. The carbon monoxide diffuses rapidly across the pulmonary capillary membrane binding to the haem molecule with a very high affinity (240 times that of oxygen) forming carboxy-haemoglobin (COHb). Non-smokers have a baseline COHb of ,3% while smokers have a baseline COHb of 10-15%.Use of Hyperbaric oxygen therapy (HBOT) for treatment of mild to moderate CO poisoning is not routine.The selection criteria for HBOT in cases of CO poisoning include:• COHb levels > 20-25%• COHb levels > 20% in pregnant patient • Loss of consciousness• Severe metabolic acidosis (pH <7.1)• Evidence of end-organ ischemia (e.g., ECG changes, chest pain, or altered mental status)Principle of HBOT:Exposing patients to 100 percent oxygen under supra-atmospheric conditions results in a decrease in the half-life (t1/2) of COHb, from , 90 min in atmospheric air to , 30 minutes. The amount of oxygen dissolved in the blood also rises from , 0.3 to 6 mL/dL, increasing the delivery of non-haemoglobin-bound oxygen to the tissues.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 199
Incorrect
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Which of the following does not contribute to increased stroke volume during exercise?
Your Answer:
Correct Answer: Increased length of filling time during diastole
Explanation:Prolonged aerobic exercise training may also increase stroke volume, which frequently results in a lower (resting) heart rate. Reduced heart rate prolongs ventricular diastole (filling), increasing end-diastolic volume, and ultimately allowing more blood to be ejected.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 200
Incorrect
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Tumour necrosis factor is a cytokine. What is its major function?
Your Answer:
Correct Answer: Promotion of inflammation
Explanation:Tumour necrosis factor (TNF) is a cytokine that has a wide variety of functions. It can cause cytolysis of certain tumour cell lines; it is involved in the induction of cachexia; it is a potent pyrogen, causing fever by direct action or by stimulation of interleukin-1 secretion; it can stimulate cell proliferation and induce cell differentiation under certain conditions.
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This question is part of the following fields:
- Immunology
- Medicine
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SESSION STATS - PERFORMANCE PER SPECIALTY
