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Question 1
Correct
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Treatment of an acute attack of gout with allopurinol may result in which of the following?
Your 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 2
Correct
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The pathogen in variant Creutzfeldt Jacobs disease is an example of a:
Your Answer: Prion
Explanation:Types of Creutzfeldt Jacobs Disease (CJD) include:1. variant – This is thought to be caused by the consumption of food contaminated with prions, which also cause BSE.2. sporadic – This accounts for 85% of cases of CJD. 3. familial – This accounts for the majority of the other 15% cases of CJD.4. iatrogenic – This form of CJD arises from contamination with tissue from an infected person, usually as the result of a medical procedure.
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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Question 3
Correct
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In Argyll Robertson pupils…
Your Answer: All of the options given
Explanation:Argyll Robertson pupils are bilaterally small pupils that accommodate or reduce in size near an object but do not react to light. They do not constrict when exposed to bright light. They are a highly specific sign of neurosyphilis but may be seen in diabetic neuropathy as well.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 4
Correct
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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 5
Correct
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At rest, proton pumps are sequestered within the parietal cell in a series of membrane compartments known as:
Your Answer: Tubulovesicles
Explanation:The gastric H, K-ATPase pump, which pumps gastric acid (HCl), in the resting state is found in cytoplasmic tubular membranes. In the stimulated state this pump moves from the tubulovesicles to the apical membrane.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 6
Correct
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Which statement about X linked dominant disorders is FALSE?
Your Answer: Heterozygous females tend to have the disease more severely than affected males.
Explanation:Women who have the affected X chromosome will be affected, but the severity will be less than that in males as they have a normal X chromosome to counter the effect of the mutated X chromosome. Affected males will pass on the defect to their daughters 100% of the time but not to their sons.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 7
Incorrect
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Which of the following causes an increase in venous return?
Your Answer: Peripheral vasodilatation
Correct Answer: An increase in the negative intra-thoracic pressure
Explanation:During inspiration, intrathoracic pressure becomes more negative and intra-abdominal pressure more positive. This increases the venous pressure gradient from abdomen to thorax and promotes filling of the central veins.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 8
Correct
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The structure of haemoglobin A in adults includes
Your Answer: Haem, globin polypeptide chains α and β
Explanation:Haemoglobin A (HbA), also known as adult haemoglobin or α2β2, is the most common human haemoglobin tetramer, comprising over 97% of the total red blood cell haemoglobin. It consists of two alpha chains and two beta chains.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 9
Incorrect
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Which of the following is not true regarding mitochondrial chromosome disorders?
Your Answer: Most mitochondrial diseases are myopathies and neuropathies with a maternal pattern of inheritance
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 10
Correct
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Question 11
Correct
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All of the following features may suggest malignant changes in a melanocytic naevi, EXCEPT?
Your Answer: Decrease in size
Explanation:Melanocytic naevi are skin tumours produced by melanocytes. They usually present in childhood but increase during puberty. The mnemonic A-B-C-D, is used by institutions to assess for suspicion of malignancy. The letters stand for asymmetry, border, colour, and diameter. If a mole starts changing in size, colour, shape or, especially, if the border of a mole develops ragged edges or becomes larger than a pencil eraser, it would be an appropriate time to consult with a physician. Other warning signs include if it begins to crust over, bleed, itch, or become inflamed.
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This question is part of the following fields:
- Dermatology
- Medicine
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Question 12
Correct
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Which of the following forms the language areas of the cerebral cortex?
Your Answer: All of the above
Explanation:Broca’s area, Wernicke’s area, the submarginal sulcus and the angular gyrus all form the language areas of the cerebral cortex.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 13
Incorrect
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Where is Basic Electrical rhythm initiated
Your Answer: Antegrade neurons
Correct Answer: Interstitial cells of cajal
Explanation:The interstitial cells of Cajal are specialized pacemaker cells located in the wall of the stomach, small intestine, and large intestine. These cells are connected to the smooth muscle via gap junctions and the myenteric plexus. The cell membranes of the pacemaker cells undergo a rhythmic depolarization and repolarization from -65mV to -45mV. This rhythm of depolarization-repolarization of the cell membrane creates a slow wave known as a basic electrical rhythm (BER), and it is transmitted to the smooth muscle cells.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 14
Correct
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With regards to P53, which statement is NOT true?
Your Answer: P53 is a RNA binding protein
Explanation:P53 is a tumour suppressor gene. It is not an RNA binding protein. It has been implicated in almost all tumours. It regulates the progression from G1 to the S phase of the cell cycle and is activated in response to damaged DNA.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 15
Correct
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Intrinsic Factor is released by,
Your Answer: Parietal cell
Explanation:Intrinsic factor (IF), also known as gastric intrinsic factor (GIF), is a glycoprotein produced by the parietal cells of the stomach. It is necessary for the absorption of vitamin B12 (cobalamin) later on in the small intestine.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 16
Correct
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The function of Troponin T in cardiac muscle is?
Your Answer: Allows attachment of troponin components to tropomyosin
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 17
Correct
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Which one of the following ECG findings is least associated with digoxin use?
Your Answer: Prolonged QT interval
Explanation:Digoxin ECG features:• ST depression (‘reverse tick’)• flattened/inverted T waves• Prolonged PR interval• short QT interval• arrhythmias e.g. AV block, bradycardia, ventricular tachycardia or fibrillation (for example paroxysmal atrial tachycardia with A-V block – so-called PAT with block) is said to be pathognomonic (i.e. diagnostic) of digoxin toxicity.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 18
Correct
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Into how many functional units can the cerebellum be divided?
Your Answer: 3
Explanation:The functional division of the cerebellum are the: Vestibulocerebellum (floculonodular lobe), Spinocerebellum (vermis and associated areas in the midline) and cerebrocerebellum (lateral hemispheres).
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This question is part of the following fields:
- Medicine
- Neurology
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Question 19
Correct
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Which of the following is the most common clinical feature of carbon monoxide poisoning?
Your Answer: Headache
Explanation:Carbon monoxide (CO) poisoning:It is 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%.Clinical features of carbon monoxide toxicity:Headache: 90% of cases (most common clinical feature)Nausea and vomiting: 50%Vertigo: 50%Confusion: 30%Subjective weakness: 20%Severe toxicity: ‘pink’ skin and mucosa, hyperpyrexia, arrhythmias, extrapyramidal features, coma, deathCherry red skin is a sign of severe toxicity and is usually a post-mortem finding.Management• 100% oxygen• Hyperbaric oxygen therapy (HBOT)The use of Hyperbaric oxygen therapy (HBOT) for treatment 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)
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 20
Correct
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Which receptor type is associated with the inhibition of pancreatic endocrine secretion?
Your Answer: Α2
Explanation:The activation of alpha 2-adrenergic receptors in pancreatic beta-cells works by inhibiting the secretion of insulin.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 21
Correct
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Which one of the following is necessary to activate plasminogen to plasmin?
Your 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 22
Correct
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A 18-year-old female is brought to the emergency department by her boyfriend. He is concerned that she may have taken an overdose of her mom's morphine sulphate pills after being depressed about her mother, who is dying of carcinoma of the breast.Which of the following may point towards his suspicion?
Your Answer: Sweating
Explanation:Excessive sweating points towards a morphine overdose.Morphine is considered the classic opioid analgesic with which other painkillers are compared. Like other medications in this class, morphine has an affinity for delta, kappa, and mu-opioid receptors.Most commonly used in pain management, morphine provides major relief to patients afflicted with pain.Among the more common adverse effects of morphine use is constipation. Other side effects include nausea, vomiting, drowsiness, and confusion. Psychological and physical dependence may occur.Other side effects include bronchospasm, angioedema, urinary retention, ureteric or biliary spasm, dry mouth, sweating, rash, facial flushing, vertigo, tachycardia, bradycardia, palpitations, orthostatic hypotension, hypothermia, restlessness, mood change, hallucinations, seizures (adults and children) and miosis, headache and allergic reactions (including anaphylaxis) and decreased libido or potency.Raised intracranial pressure occurs in some patients. Muscle rigidity may occur with high doses. Elevated liver enzymes may occur due to biliary sphincter constriction. Large doses can lead to respiratory depression, circulatory failure, and coma.Treatment of opioid overdose:Initial treatment of overdose begins with supportive care.Naloxone is a pure competitive antagonist of opiate receptors and has no agonistic activity. The drug is relatively safe and can be administered intravenous, intramuscular, subcutaneous or via the endotracheal tube.Alternatively, nalmefene and naltrexone maybe considered.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 23
Incorrect
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A 34-year-old man was brought to the ER following a road-traffic-accident. An X-ray of his left thigh revealed a fractured shaft of the left femur. He has a known history of opioid abuse. You are called to the ward to assess him after he becomes unwell. Which of the following clinical features are NOT compatible with a diagnosis of opioid withdrawal?
Your Answer: Diarrhoea
Correct Answer: Hypothermia
Explanation:Among the options provided, hypothermia is not a symptom of opioid withdrawal.Symptoms of opioid withdrawal include dysphoric mood, yawning, insomnia, muscle aches, lacrimation/rhinorrhoea, papillary dilatation, piloerection, fever, sweating, nausea/vomiting, diarrhoea.If the patient is having an opioid withdrawal reaction, then give 10 mg of methadone syrup and wait about 60 min to determine its effect.COWS (Clinical Opioid Withdrawal Scale) assessment for opioid withdrawal is commonly used to determine the severity of opioid withdrawal.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 24
Correct
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Dynein proteins transmit polypeptides/proteins in which direction?
Your Answer: From axons terminals to cell body (retrograde)
Explanation:The majority of axonal proteins are synthesised in the cell body and transported along the axons. Microtubules run along the length of the axon and provide tracks for transportation. Kinesin and Dynein are motor proteins that transport proteins and other organelles. Kinesin moves forward or anterograde transport from cell body to axon, whereas Dynein moves retrograde from axon to cell body.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 25
Correct
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Which inhibitor of gastric enzyme secretion is released by the presence of fat in the jejunum?
Your Answer: Peptide yy
Explanation:Peptide yy is secreted from the jejunum due to the presence of fat. It inhibits gastric acid secretion and motility.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 26
Correct
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The first enzyme carbohydrates encounter in the digestive tract is?
Your Answer: Amylase
Explanation:Carbohydrate digesting enzymes are known as amylase. Salivary amylase or ptyalin is the first enzyme to begin carbohydrate digestion in he oral cavity. Amylose is a component of carbohydrates and is not an enzyme. Isomaltase, maltase and sucrase are enzymes found in the small intestines that digest disaccharides like maltose and sucrose to monosaccharides.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 27
Correct
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Which statement is incorrect regarding nociceptor C fibers…
Your Answer: They are thinly myelinated
Explanation:Group C nerve fibers are unmyelinated and have a small diameter, which means they conduct impulses at a low velocity. They carry sensory information and nociception.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 28
Correct
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The haustral pattern seen in the normal colon is produced by
Your Answer: Taenia coli
Explanation:The haustra (singular haustrum) of the colon are the small pouches caused by sacculation (sac formation), which give the colon its segmented appearance. The teniae coli run the length of the large intestine. Because the taeniae coli are shorter than the intestine, the colon becomes sacculated between the taeniae coli, forming the haustra.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 29
Correct
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The Afferent neuron that supplies all sensory elements of the muscle spindle is what type of sensory neuron?
Your Answer: Ia
Explanation:Muscle spindle is supplied by both sensory and motor nerves. Sensory supply is Type Ia fibers whereas motor supply is gamma motor neurone.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 30
Correct
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Which glucose transporter is responsible for the uptake of dietary glucose from the gut?
Your Answer: SGLT1
Explanation:SGLT 1 is responsible for the uptake of glucose via secondary active transport from the small intestine and the renal tubules.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 31
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 32
Correct
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A 26 year old male presents with right sided elbow and wrist pain and left sided knee and ankle pain that has persisted for about two weeks. He recently returned from a trip to Thailand that last for two weeks. The patient admits to having unprotected sex while on holiday. Examination reveals swelling and tenderness of tendons around joints but no inflammation of the joints. A vesiculopustular skin rash is also observed. What is the most likely cause?
Your Answer: Gonococcal arthritis
Explanation:Patients with disseminated gonococcal arthritis may present with dermatitis-arthritis syndrome (60%) of with localized septic arthritis. (40%). Arthritis-dermatitis syndrome includes the classic triad of dermatitis, tenosynovitis, and migratory polyarthritis. Gout usually involves a singe joint and does not cause vesicopustular skin rash. Reactive arthritis has ocular symptoms (conjunctivitis), urethritis, and arthritis. Fungal arthritis occurs rarely and it may occur after a surgical infection or fungal spread hematogenously. it presents with tender, red, hot and swollen joint with loss of range of motion.
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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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A 68 year old man presents with acute symptoms of gout on his first metatarsophalangeal joint. Which option best explains the underlying mechanism of gout?
Your Answer: Increased endogenous production of uric acid
Correct Answer: Decreased renal excretion of uric acid
Explanation:Primary gout is related more often to underexcretion of uric acid or overproduction.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 34
Correct
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Di and tri peptides are absorbed via a different mechanism as amino acids, this is due to the working of which transporter?
Your Answer: PEPT 1
Explanation:GLUT and SGLT are glucose transporters. Peptides which are longer that four amino acids are not absorbed. There is abundant absorption of di and tri peptidases in the small intestine. They are absorbed into the epithelial cells of the small intestine via a transporter called PepT1 by co-transport with H+ ions.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 35
Incorrect
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Transport of Ca2+ into the reticulum to initiate cardiac muscle relaxation in via:
Your Answer: Dihydropyridine receptors
Correct Answer: Serca (sarcoplasmic or endoplasmic reticulum Ca2+ ATPase)
Explanation:Phosphorylation of phospholamban, which increases calcium ATPase activity and sequestration of calcium in the sarcoplasmic reticulum. An increased rate of relaxation is explained because cAMP also activates the protein phospholamban, situated on the membrane of the SR, that controls the rate of uptake of calcium into the SR. The latter effect explains enhanced relaxation (lusitropic effect).
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 36
Correct
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The basic taste “umami” is mediated by glutamate acting on a metabotropic receptor named:
Your Answer: mGluR4
Explanation:Umami taste or savoury taste is one of the five basic tastes described as meaty or brothy. Umami taste receptors typically respond to Glutamate. Biochemical studies have identified the taste receptors responsible for the sense of umami as modified forms of mGluR4, mGluR1 and taste receptor type 1 (T1R1), all of which have been found in all regions of the tongue bearing taste buds.
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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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Calcium induced calcium release occurs in the sarcoplasmic reticulum by activation of which receptors
Your Answer: Ryanodine receptors
Explanation:Calcium-induced calcium release (CICR) describes a biological process whereby calcium is able to activate calcium release from intracellular Ca2+ stores (e.g., endoplasmic reticulum or sarcoplasmic reticulum). CICR occurs when the resulting Ca2+ influx activates ryanodine receptors on the SR membrane, which causes more Ca2+ to be released into the cytosol.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 38
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 39
Correct
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Question 40
Incorrect
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Bone marrow barrier is important to:
Your Answer: All of the above
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 41
Correct
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Which of the following types of reactions are a part of the phase II metabolism of a drug?
Your Answer: Conjugation
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 42
Correct
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Synthesis of haem for haemoglobin occurs in the?
Your Answer: Mitochondria of the red blood 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.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 43
Correct
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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 44
Correct
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A 50-year-old patient was started on ezetimibe, for his cholesterol a few days back. Which among the following statements is true regarding ezetimibe?
Your Answer: Its principal action is to reduce intestinal cholesterol absorption
Explanation:Ezetimibe is a cholesterol-lowering agent that acts to prevent cholesterol absorption by directly inhibiting cholesterol receptors on enterocytes.It does not affect the absorption of drugs (e.g. digoxin, thyroxine) or fat-soluble vitamins (A, D and K) as the anion-exchange resins do. It does not affect the cytochrome P450 enzyme system.The increased risk of myositis associated with the statins is not seen with ezetimibe.The most common adverse effects include headache, runny nose, and sore throat. Less common reactions include body aches, back pain, chest pain, diarrhoea, joint pain, fatigue, and weakness.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 45
Correct
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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: 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
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Question 46
Correct
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Which cell type functions as the critical bridge between innate and adaptive immune systems, by activating naïve T lymphocytes?
Your Answer: Dendritic cells
Explanation:Dendritic cells are antigen presenting cells. They express class II MHC and T cell co-stimulatory molecules. They bind antigens and present them to native T cells and in the process activate the specific T cell against that antigen.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 47
Correct
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Question 48
Correct
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A 25-year-old male presented to accident and emergency 4 days ago, following an intentional paracetamol overdose. He had taken 20x 500mg tablets, all at once. He denies any alcohol intake. Blood investigations 4 hours after ingestion showed:Paracetamol: 14 mg/lINR: 1Liver enzymes: No abnormality detectedBilirubin: Mild elevationHe was seen by the mental health team and discharged. The blood investigations were repeated:Bilirubin: Within normal limitsUrea: 21 mmol/lCreatinine: 300 µmol/lWhat is the likely cause of these results?
Your Answer: Delayed paracetamol nephrotoxicity
Explanation:The most likely cause for these results is delayed paracetamol nephrotoxicity.The blood investigations of this patient are highly suggestive of acute kidney injury. Paracetamol overdose is well known to cause hepatotoxicity, but not for its delayed nephrotoxicity, especially in significant overdose. Appropriate monitoring of a patient’s blood tests is important.Management:NAC (N-Acetyl cysteine) has a clear role in preventing acetaminophen-induced liver necrosis. Although NAC has not been proven to be harmful to the kidney, its role in patients without hepatoxicity and only isolated renal dysfunction is uncertain.Other options:-There are no features in the history that are suggestive of dehydration and pre-renal AKI presenting in this manner in a 25-year-old would be very unusual.- Minimal change nephropathy typically presents with a nephrotic picture of kidney injury.- Berger’s more commonly presents with isolated haematuria.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 49
Incorrect
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Which of the following substances inhibits pancreatic secretion?
Your Answer: Cholecystokinin
Correct Answer: Pancreatic polypeptide
Explanation:Number of hormones and neurotransmitters can stimulate and inhibit pancreatic exocrine secretion. Cholecystokinin, secretin, vasoactive intestinal peptide and substance P stimulate pancreatic secretion. Pancreatic polypeptide, somatostatin inhibit pancreatic secretion.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 50
Correct
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Why is tissue plasminogen activator (tPa) a valuable treatment used in myocardial infarction and stroke?
Your Answer: It forms plasmin from its inactive precursor
Explanation:tPA is a serine protease involved in the breakdown of blood clots. It functions by converting plasminogen, an inactive precursor, into plasmin, an active enzyme. Plasmin then degrades fibrin, the main protein component of blood clots, leading to clot dissolution. This mechanism is particularly valuable in the treatment of myocardial infarction (heart attack) and ischemic stroke, where timely dissolution of the clot can restore blood flow to affected tissues and reduce damage.
Therefore, the correct answer is:
- It forms plasmin from its inactive precursor
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This question is part of the following fields:
- Haematology
- Medicine
-
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Question 51
Correct
-
Which is the most common site for primary cardiac tumours to occur in adults?
Your Answer: Left atrium
Explanation:Myxomas are the most common type of primary heart tumour. The tumour is derived from multipotential mesenchymal cells and may cause a ball valve-type obstruction. About 75% of myxomas occur in the left atrium of the heart, usually beginning in the wall that divides the two upper chambers of the heart.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 52
Incorrect
-
Two types of gallstones are:
Your Answer: Bilirubinate and carbonate
Correct Answer: Calcium and cholesterol
Explanation:Cholesterol stones are the most common gallstones followed by calcium carbonate and bilirubinate.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
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Question 53
Incorrect
-
A 30-year-old female presented with upper abdominal pain. She was diagnosed with an unknown coagulopathy and has a previous history of stroke. She has been on warfarin therapy for the past 4 months. Her international normalised ratio (INR) was stabilised between 2.5 and 3.0. Noticing abnormal coagulation results, her surgeon has requested a medical consult.Her blood investigations revealed:White cell count: 13 × 109/lHaemoglobin (Hb): 11 g/dlActivated partial thromboplastin time (APTT): NormalPlatelets: 140 × 109/lINR: 6.0Pancreatic enzymes and liver function tests were normal.Other investigations:An ultrasound of the abdomen was normal.An upper GI endoscopy revealed mild gastritis. What is the most appropriate step to be taken regarding warfarin therapy?
Your Answer: Give vitamin K 5.0 mg intravenously
Correct Answer: Stop warfarin and observe
Explanation:The most appropriate treatment in this patient would be to stop warfarin therapy and keep the patient under observation.The drugs that lead to enhanced potency of warfarin include: disulfiram, trimethoprim-sulphamethoxazole, metronidazole, phenylbutazone, aspirin, heparin, and clofibrate. Liver disease, thrombocytopenia, hyperthyroidism also increase the oral anticoagulant potency.If the patient has minor bleeding and the international normalized ratio (INR) is >6.0, warfarin should be stopped; the INR should be rechecked daily and in addition to the stoppage of warfarin, vitamin K 2.5 mg oral or 0.5 mg intravenously should also be administered.In a patient with INR of 2.0 or 3.0, it takes two or three times longer for that individual’s blood to clot than someone who is not taking any anticoagulants. Most patients on warfarin have an INR goal of 2 to 3.If there is major bleeding then prothrombin complex concentrates 50 u/kg or fresh-frozen plasma 15 ml/kg may be considered.
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This question is part of the following fields:
- Medicine
- Pharmacology
-
-
Question 54
Incorrect
-
What causes increased insulin sensitivity?
Your Answer: Catecholamine release
Correct Answer: Exercise
Explanation:Physical activity, through its effect on insulin sensitivity, is one of the main modifiable risk factors for type 2 diabetes. It is estimated that by each weekly 500 kcal increment in exercise related energy consumption, the lifetime risk of suffering from type 2 diabetes is reduced by 9%. Up to two hours after exercise, glucose uptake is elevated due to insulin independent mechanisms; however, insulin sensitivity remains increased for at least 16 hours after exercising.
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This question is part of the following fields:
- Endocrinology
- Medicine
-
-
Question 55
Correct
-
Which of the following is NOT a pancreatic enzyme?
Your Answer: Pepsinogen 1
Explanation:Pancreatic juice, composed of the secretions of both ductal and acinar cells, is made up of the following digestive enzymes:Trypsinogen, which is an inactive(zymogenic) protease that, once activated in the duodenum into trypsin, breaks down proteins at the basic amino acids. Trypsinogen is activated via the duodenal enzyme enterokinase into its active form trypsin.Colipase is a protein co-enzyme required for optimal enzyme activity of pancreatic lipase. It is secreted by the pancreas in an inactive form, procolipase, which is activated in the intestinal lumen by trypsin.Chymotrypsinogen, which is an inactive (zymogenic) protease that, once activated by duodenal enterokinase, breaks down proteins at their aromatic amino acids. Chymotrypsinogen can also be activated by trypsin.Carboxypeptidase, which is a protease that takes off the terminal amino acid group from a proteinSeveral elastases that degrade the protein elastin and some other proteins.Pancreatic lipase that degrades triglycerides into fatty acids and glycerol.Sterol esterasePhospholipaseSeveral nucleases that degrade nucleic acids, like DNase and RNase.Pancreatic amylase that breaks down starch and glycogen which are alpha-linked glucose polymers.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 56
Correct
-
The Plateau phase in myocyte action potentials does all of the following except:
Your Answer: It allows early reactivation of the myocytes
Explanation:The presence of the plateau in the action potential causes ventricular contraction to last as much as 15 times longer in cardiac muscle as in skeletal muscle. The plateau phase which follows is unique to myocytes and results from a small, but sustained inward calcium current through L-type calcium channels lasting 200-400 ms. This calcium influx is caused by a combined increase in permeability of the cell and especially the sarcolemmal membranes to calcium. This plateau (refractory) phase prevents early reactivation of the myocytes and directly determines the strength of contraction.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 57
Correct
-
Which one of the following neurotransmitters is considered a monoamine?
Your Answer: Dopamine
Explanation:Monoamines are a class of neurotransmitters that include:
- Dopamine: A neurotransmitter involved in reward, motivation, and motor control.
- Norepinephrine: A neurotransmitter involved in arousal, attention, and stress responses.
- Serotonin: Although not listed in the options, it is another key monoamine involved in mood regulation.
The other neurotransmitters listed are not monoamines:
- Acetylcholine: This is a different type of neurotransmitter involved in muscle activation and various brain functions.
- GABA (gamma-aminobutyric acid): This is the main inhibitory neurotransmitter in the central nervous system.
- Glutamate: This is the main excitatory neurotransmitter in the central nervous system.
- Glycine: An inhibitory neurotransmitter in the central nervous system.
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This question is part of the following fields:
- Medicine
- Neurology
-
-
Question 58
Incorrect
-
Which of the following involving the scalp may produce alopecia (hair loss)?
Your Answer: Seborrheic dermatitis
Correct Answer: Discoid lupus erythematosus
Explanation:Causes of hair loss include:
- Dissecting cellulitis
- Fungal infections (such as tinea capitis)
- Folliculitis
- Secondary syphilis
- Demodex folliculorum
- Lupus erythematosus (hair loss may be permanent due to scarring of the hair follicles).
Psoriasis and seborrheic dermatitis commonly involve the scalp but do not produce hair loss.
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This question is part of the following fields:
- Dermatology
- Medicine
-
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Question 59
Correct
-
All of the following constitute small intestinal brush border enzymes except:
Your Answer: Alpha-amylase
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 which extend from the cell known as the brush border. Thus, the enzymes embedded in those microvilli are referred to as brush border enzymes. All these enzymes except alfa amylase are brush border enzymes. Alfa amylase is secreted by pancreatic acinar cells.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 60
Correct
-
Regarding the myofilament molecules, which of the following contains binding sites for calcium that helps to initiate contraction?
Your 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 61
Correct
-
Stimulation of the carotid sinus results in:
Your 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 62
Correct
-
In the clotting mechanism, activation of factor IX can occur through the direct actions of:
Your Answer: Factor VIIa & XIa
Explanation:Factor IX is processed to remove the signal peptide, glycosylated and then cleaved by factor XIa (of the contact pathway) or factor VIIa (of the tissue factor pathway). When activated into factor IXa, in the presence of Ca2+, membrane phospholipids, and a Factor VIII cofactor, it hydrolyses one arginine-isoleucine bond in factor X to form factor Xa. Factor IX is inhibited by antithrombin.
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This question is part of the following fields:
- Haematology
- Medicine
-
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Question 63
Correct
-
How are the long chain fatty acids (more than 10 to 12 carbon atoms) absorbed?
Your Answer: Re-esterified to triglycerides and enter the lymphatics as chylomicrons
Explanation:Short and medium chain fatty acids are absorbed into the blood via intestinal capillaries and travel through the portal vein. Long chain fatty acids are not directly released into the intestinal capillaries. They are re-esterified to triglycerides and are coated with cholesterol and protein, forming chylomicrons. Chylomicrons are released in the lymphatic system.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 64
Correct
-
Regarding the innervation of cerebral blood vessels, which of the following triggers a vasoconstrictor effect?
Your Answer: Neuropeptide-Y
Explanation:Substance P is a potent vasodilator, VIP or vasoactive intestinal peptide has vasodilator properties in the intestines. PHM 27 is a potent calcitonin receptor agonist; endogenous analogue of human VIP. CGRP or Calcitonin Gene-Related Peptide is a vasodilator which is found to play an important role in migraines. Neuropeptide Y is a strong vasoconstrictor.
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This question is part of the following fields:
- Medicine
- Neurology
-
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Question 65
Incorrect
-
Calcium needed for cardiac muscle contraction is made available during which phase of the action potential?
Your Answer: 3
Correct Answer: 2
Explanation:It is made available during the plateau phase of the action potential i.e. phase 2. During the plateau phase of the action potential, Calcium from the extracellular fluid enters through the L type of calcium channels. This entry triggers the release of more calcium from the sarcoplasmic reticulum via the ryanodine receptors.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 66
Incorrect
-
When during the cell cycle does DNA replication occur?
Your Answer: Mitosis
Correct Answer: S phase
Explanation:The S phase is known as the synthesis phase. During this phase DNA will begin to replicated, as well as the synthesis of the centrosomes and associated proteins.
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This question is part of the following fields:
- Genetics
- Medicine
-
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Question 67
Incorrect
-
Transport of Iron into enterocytes occurs via which membrane transporter?
Your Answer: Ferroportin 1
Correct Answer: Divalent metal transporter 1(dmt1)
Explanation:To be absorbed, dietary iron can be absorbed as part of a protein such as haem protein or iron must be in its ferrous Fe2+ form. A ferric reductase enzyme on the enterocytes’ brush border, duodenal cytochrome B (Dcytb), reduces ferric Fe3+ to Fe2+. A protein called divalent metal transporter 1 (DMT1), which can transport several divalent metals across the plasma membrane, then transports iron across the enterocyte’s cell membrane into the cell.
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This question is part of the following fields:
- Haematology
- Medicine
-
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Question 68
Correct
-
Which of the following associations is false?
Your Answer: Mandibular nerve – foramen lacerum
Explanation:– The olfactory nerves pass through the cribriform plate- The maxillary division of the trigeminal nerve passes through the foramen rotundum- The facial nerve passes through the stylomastoid foramen- The mandibular division of the trigeminal nerve pass through the foramen ovale- The glossopharyngeal nerve passes through the jugular foramen.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 69
Correct
-
Organophosphates, such as Sarin, have been used as chemical-warfare agents by terrorists. Which of the following statements is true concerning organophosphate poisoning?
Your Answer: Atropine is useful in the management of organophosphate poisoning
Explanation:The principal action of organophosphates is the inhibition of acetylcholinesterase’s, therefore leading to the accumulation of acetylcholine at muscarinic receptors (miosis, hypersalivation, sweating, diarrhoea, excessive bronchial secretions), nicotinic receptors (muscle fasciculations and tremor) and in the central nervous system (anxiety, loss of memory, headache, coma). Removal from the source of the organophosphate, adequate decontamination, supplemental oxygen and atropine are the initial treatment measures. Pralidoxime, an activator of cholinesterase, should be given to all symptomatic patients.
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This question is part of the following fields:
- Medicine
- Pharmacology
-
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Question 70
Incorrect
-
On which chromosome is the gene for insulin located?
Your Answer: Chromosome 6
Correct Answer: Chromosome 11
Explanation:Humans have 23 pairs of chromosomes, and usually, two pairs of copies of chromosome 11. It is one of the most complex, gene-rich chromosomes in the human genome, and it is associated with a number of diseases. Studies have shown they the human insulin gene is located on the short arm of chromosome 11.
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This question is part of the following fields:
- Endocrinology
- Medicine
-
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Question 71
Correct
-
Question 72
Correct
-
During which stage does the mitotic apparatus dissolute?
Your Answer: Telophase
Explanation:In telophase the nuclear envelope along with the nucleolus will reappear. The daughter nuclei will enlarge as the chromosome will decondense again. Along with this, cytokinesis will occur. At the end of cytokinesis the daughter centrioles will move from the poles to the intercellular bridge where they will be disassembled and complete the separation of the daughter cells
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This question is part of the following fields:
- Genetics
- Medicine
-
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Question 73
Correct
-
Which of the following provides the sympathetic nervous supply to the stomach?
Your Answer: Coeliac plexus
Explanation:Parasympathetic innervation to the stomach is from the vagus nerve and the sympathetic innervation is from the coeliac plexus.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
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Question 74
Correct
-
A 62 year old man arrives at the clinic with a history of cough and intermittent haemoptysis for the last 3 months. He has a 50 pack year smoking history and is currently waiting for bronchoscopy to assess a left lower lobe collapse. The patient also has a marked muscle weakness and wasting of proximal muscles of his shoulders and pelvic girdle. His wife states that lately he has been unable to eat solids. Which of the following statements would be true regarding this scenario?
Your Answer: He may have a photosensitive facial rash
Explanation:The patient has presented with signs of small cell lung cancer. The associated proximal muscle weakness is most probably due to dermatomyositis which occurs as a paraneoplastic syndrome associated with lung carcinoma. In most cases, the first symptom is a distinctive skin rash on the face, eyelids, chest, nail cuticle areas, knuckles, knees or elbows. The rash is patchy and usually a bluish-purple colour. Corticosteroids are helpful in the management of the cutaneous changes and muscle weakness.
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This question is part of the following fields:
- Connective Tissue
- Medicine
-
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Question 75
Incorrect
-
Which one of the following have not been shown to improve mortality in patients with chronic heart failure?
Your Answer: Enalapril
Correct Answer: Furosemide
Explanation:A number of drugs have been shown to improve mortality in patients with chronic heart failure:
- ACE inhibitors (SAVE, SOLVD, CONSENSUS)
- spironolactone (RALES)
- beta-blockers (CIBIS)
- hydralazine with nitrates (VHEFT-1)
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 76
Correct
-
During quiet breathing the diaphragm’s role accounts for what percent of respiration?
Your Answer: 75%
Explanation:The contraction of the diaphragm accounts for approximately 75% of the air movement during normal breathing.
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This question is part of the following fields:
- Medicine
- Respiratory
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Question 77
Incorrect
-
Which of the following limits the duration of inspiration and increases respiratory rate?
Your Answer: Ventral respiratory group
Correct Answer: Pneumotaxic centre
Explanation:The mechanism of control of ventilation is an interplay of multiple regions in the brain. The medullary respiratory centre sets the basic rhythm of breathing and the pons modifies the output of the medullary centres. There are two pontine centres: apneustic and pneumotaxic.
The pnuemotaxic centre controls inspiratory time. Increased signals to this area increases respiratory rate. The dorsal respiratory group (DRG) integrates input from the stretch receptors and the chemoreceptors in the periphery and is composed mainly of inspiratory neurons. The DRG controls the basic rhythm of breathing by triggering inspiratory impulses. The ventral respiratory group (VRG) generates breathing rhythm and integrates data coming into the medulla and contains both inspiratory and expiratory neurons. They are primarily active in exercise and stress.
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This question is part of the following fields:
- Medicine
- Respiratory
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Question 78
Correct
-
Question 79
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 80
Correct
-
Southern Blotting and DNA probes:
Your Answer: DNA fragments are separated by gel electrophoresis and transferred onto membrane sheets in southern blotting
Explanation:A Southern blot is a method used in molecular biology for detection of a specific DNA sequence in DNA samples. Southern blotting combines transfer of electrophoresis-separated DNA fragments to a filter membrane and subsequent fragment detection by probe hybridization. The other forms of blotting involve the use of RNA and proteins.
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This question is part of the following fields:
- Genetics
- Medicine
-
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Question 81
Correct
-
Regarding integrins, which option is false?
Your Answer: Play no role in cell signalling.
Explanation:Integrins are transmembrane receptors that facilitate cell-extracellular matrix (ECM) adhesion. Upon ligand binding, integrins activate signal transduction pathways that mediate cellular signals such as regulation of the cell cycle, organization of the intracellular cytoskeleton, and movement of new receptors to the cell membrane. Integrins are obligate heterodimers, meaning that they have two subunits: α (alpha) and β (beta). Integrins play an important role in cell signalling by modulating the cell signalling pathways of transmembrane protein kinases such as receptor tyrosine kinases (RTK).
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This question is part of the following fields:
- Cell Biology
- Medicine
-
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Question 82
Correct
-
A 31 year old female with systemic lupus erythematosus wants to know if she has any predisposing factors for the disease. Which of the following carries the greatest risk of developing SLE?
Your Answer: Monozygotic twin
Explanation:An overall concordance rate in monozygotic twins was documented to be 25% as compared to dizygotic twins with 3%. First degree relatives have a chance of around 3% of developing the disease. Caucasians show an increase frequency of HLA-B8. The Japanese lupus patients had a stronger association with HLA-DR2.
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This question is part of the following fields:
- Connective Tissue
- Medicine
-
-
Question 83
Incorrect
-
Mean intra pleural pressure at rest with inspiration can reach:
Your Answer: -16 mmHg
Correct Answer: -6 mmHg
Explanation:It is a negative pressure as it is lower than the atmospheric pressure. It can start from -2.5 and reach around -6 mmHg
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This question is part of the following fields:
- Medicine
- Respiratory
-
-
Question 84
Incorrect
-
Concerning protein digestion:
Your Answer: Pepsinogen 1 is found in acid secreting regions as well as the pyloric region
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
-
-
Question 85
Correct
-
The axons of which neurons serve as the only output from the cerebellar cortex?
Your Answer: Purkinje
Explanation:The cerebellar cortex consist of 3 layers. The molecular layer, the granule cell layer and the Purkinje cell layer in the middle. The Purkinje cells project into the deep cerebellar nuclei. They are the only output cells of the cerebellar cortex.
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This question is part of the following fields:
- Medicine
- Neurology
-
-
Question 86
Correct
-
Question 87
Correct
-
Question 88
Correct
-
A 32 year old male who has recently returned from a trip to Thailand presents with congestion of eyes and swelling of the knee joint. He completed a course of antibiotics for dysentery 4 weeks back. He experiences no dysuria and urine examination is normal. Which further information would be most useful in establishing a diagnosis?
Your Answer: History and physical examination
Explanation:The patient most likely has reactive arthritis which is usually diagnosed on history and clinical examination. The classic triad of symptoms include conjunctivitis, urethritis and arthritis. Arthritis and conjunctivitis may occur 4-6 weeks after a gastrointestinal or genitourinary infection. Arthritis usually occurs acutely, mostly involving the lower limb and is asymmetrical. Blood culture, urine culture and arthrocentesis (joint aspiration) will not yield positive results.
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This question is part of the following fields:
- Connective Tissue
- Medicine
-
-
Question 89
Incorrect
-
What is the most important source of heat production in the body?
Your Answer: Ingestion of food
Correct Answer: Skeletal muscle contraction
Explanation:Thermogenesis is the process by which organisms produce heat. Through skeletal muscle contraction, or shivering, ATP is converted into kinetic energy, some of which converts into heat. These muscle contractions produce about 70% of total body heat.
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This question is part of the following fields:
- Endocrinology
- Medicine
-
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Question 90
Correct
-
Concerning the functional unit of the liver, which segment is most susceptible to hypoxic damage?
Your Answer: Zone 3
Explanation:From a metabolic perspective, the functional unit is the hepatic acinus (terminal acinus), each of which is centred on the line connecting two portal triads and extends outwards to the two adjacent central veins. The periportal zone I is nearest to the entering vascular supply and receives the most oxygenated blood, making it least sensitive to ischemic injury while making it very susceptible to viral hepatitis. Conversely, the centrilobular zone III has the poorest oxygenation, and will be most affected during a time of ischemia.
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This question is part of the following fields:
- Hepatobiliary
- Medicine
-
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Question 91
Correct
-
What is the function of Activated protein C?
Your Answer: Inactivates factor Va
Explanation:Activated Protein C (APC) is a crucial protein in the regulation of blood coagulation. Its primary functions include:
- Inactivating Factor Va: APC inactivates Factor Va, which is a cofactor for the conversion of prothrombin to thrombin by Factor Xa. By inactivating Factor Va, APC reduces thrombin formation, thereby acting as an anticoagulant.
- Inactivating Factor VIIIa: APC also inactivates Factor VIIIa, another cofactor that assists Factor IXa in the conversion of Factor X to Factor Xa. This further contributes to its anticoagulant effect.
These actions help to regulate blood clotting and prevent excessive thrombosis.
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This question is part of the following fields:
- Haematology
- Medicine
-
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Question 92
Correct
-
Which factor produced by the endothelium is responsible for the regulation of vascular cell growth?
Your Answer: Vascular endothelial growth factor (VEGF)
Explanation:VEGF is produced by the endothelial cells and is the major growth factor responsible for causing vasculogenesis. Some isoforms of this growth factor also have a prominent role in formation of lymphatic vessels.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 93
Correct
-
Defects in chromosomal structure (and examples) include those mentioned below except:
Your Answer: Lyonization (x-linked disorders)
Explanation:All are true except for A) Lyonization which is the inactivation of the X chromosomes in a female. It is not a chromosomal abnormality.
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This question is part of the following fields:
- Genetics
- Medicine
-
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Question 94
Correct
-
Which one of the following nerve fibers has the fastest conduction velocity?
Your Answer: α fiber
Explanation:α nerve fibers are characterized by being highly myelinated, which confers them with fast conduction properties. They innervate extrafusal skeletal muscle fibers, and their conduction velocity is between 80-120 m/s.
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This question is part of the following fields:
- Medicine
- Neurology
-
-
Question 95
Incorrect
-
The intestine is lined by:
Your Answer: Simple 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 96
Correct
-
Xanthines (for example Caffeine), exhibit their positive inotropic effect by:
Your Answer: Inhibiting the breakdown cAMP
Explanation:Xanthines exert their positive inotropic effect by inhibiting the breakdown of the cAMP resulting in stronger and sustained contraction.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 97
Incorrect
-
Myelin sheath in the CNS is produced by?
Your Answer: Schwann cells
Correct Answer: Oligodendrocytes
Explanation:CNS myelin is produced by special cells called oligodendrocytes. PNS myelin is produced by Schwann cells. The two types of myelin are chemically different, but they both perform the same function — to promote efficient transmission of a nerve impulse along the axon.
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This question is part of the following fields:
- Medicine
- Neurology
-
-
Question 98
Correct
-
When during the cell cycle do the centrioles replicate?
Your Answer: G1 phase
Explanation:During G1 phase the cell will prepare for cell division. All the organelles will start to duplicate in this phase and the cell will begin to grow whilst proteins are also synthesized.
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This question is part of the following fields:
- Genetics
- Medicine
-
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Question 99
Correct
-
The celiac trunk consists of which arteries?
Your Answer: Left gastric, common hepatic, splenic
Explanation:The celiac trunk is the first major branch of the abdominal aorta. It is 1.25 cm in length. Branching from the aorta at thoracic vertebra 12 (T12). There are three main divisions of the celiac artery:- left gastric artery- common hepatic artery- splenic artery
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 100
Correct
-
Presence of which of the following indicates a worse prognosis in rheumatoid arthritis?
Your Answer: Anti-CCP antibodies
Explanation:Rheumatoid arthritis is both common and chronic, with significant consequences for multiple organ systems. Anti-cyclic citrullinated peptide (anti-CCP) antibody testing is particularly useful in the diagnosis of rheumatoid arthritis, with high specificity, presence early in the disease process, and ability to identify patients who are likely to have severe disease and irreversible damage. However, its sensitivity is low, and a negative result does not exclude disease. Anti-CCP antibodies have not been found at a significant frequency in other diseases to date, and are more specific than rheumatoid factor for detecting rheumatoid arthritis. The other factors that are mentioned do not play a key prognostic role.
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This question is part of the following fields:
- Connective Tissue
- Medicine
-
-
Question 101
Correct
-
The hyperpolarization phase of pacemaker cells is dominated by ____ current.
Your Answer: K+
Explanation:The hyperpolarization phase is a continuation of the repolarization phase but the membrane potential dips below the resting membrane potential. This results due to the fact that the K+ channels take a longer time to close than the Na+ channels. Hence efflux of the K+ will result in hyperpolarization.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 102
Incorrect
-
Where do the spinothalamic axons decussate?
Your Answer: Medulla
Correct 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 103
Correct
-
The main reason for the prolonged effect of the withdrawal reflex is:
Your Answer: Multiple connections between afferent and efferent neurons
Explanation:The withdrawal reflex is a spinal reflex that protects the body from harmful stimuli. Spinal reflexes are mostly monosynaptic and are mediated by a simple reflex arc. Withdrawal reflex is mediated by a polysynaptic reflex resulting in stimulation of many motor neurons in order to establish a quick and prolonged response.
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This question is part of the following fields:
- Medicine
- Neurology
-
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Question 104
Correct
-
Which of the following is true of the Natriuretic hormones?
Your Answer: They are released in response to hypervolemia
Explanation:Natriuretic hormones are vasodilators released in response to hypervolemia.
Natriuretic hormones (NH) include three groups of compounds: the natriuretic peptides NPs (ANP, BNP and CNP), the gastrointestinal peptides (guanylin and uroguanylin), and endogenous cardiac steroids. These substances induce the kidney to excrete sodium and therefore participate in the regulation of sodium and water homeostasis, blood volume, and blood pressure (BP). In addition to their peripheral functions, these hormones act as neurotransmitters or neuromodulators in the brain.
Atrial natriuretic peptide (ANP) plays a crucial role in blood pressure regulation by inducing natriuresis and diuresis in the kidney, inhibiting renin secretion, aldosterone production, and promoting vasorelaxation. Two paracrine factors derived from endothelial cells play important roles in modulating ANP secretion. Endothelin, a potent vasoconstrictor, stimulates ANP secretion and augments stretch induced ANP secretion. The dramatic increase in ANP release produced by cardiac ischemia appears to be mediated in part by endothelin. Nitric oxide (NO), an important vasodilator, is also produced by endothelial cells and inhibits ANP secretion.
Brain natriuretic peptide (BNP) shares ANP’s receptor but is primarily associated with antifibrotic effects in ventricular remodeling, serving as a biomarker for heart failure and myocardial infarction.
C-type natriuretic peptide (CNP) acts locally in an autocrine/paracrine manner, exerting potent cardiovascular effects, including vasorelaxation and vascular remodeling post-injury. NPs also demonstrate diverse effects beyond cardiovascular and renal systems, such as bronchodilation, anti-inflammatory actions, and metabolic effects on adipose tissue and long bones.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 105
Correct
-
When is the blood pressure at its lowest during pregnancy?
Your Answer: Second trimester
Explanation:It is lowest during the second trimester.
Previous studies have reported changes in blood pressure (BP) throughout pregnancy, and it was generally accepted that in clinically healthy pregnant women, BP falls gradually at first trimester, reaching the lowest around 22–24 weeks, rising again from 28 weeks, and reaching preconception levels by 36 weeks of gestation
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 106
Correct
-
A 43 year old man with hemochromatosis presents with a painful and swollen right knee. X-ray shows extensive chondrocalcinosis but no fracture. Given the most likely diagnosis, which of the following would be present in the joint fluid aspirate?
Your Answer: Positively birefringent rhomboid-shaped crystals
Explanation:Pseudogout is a paroxysmal joint inflammation due to calcium pyrophosphate crystal deposition (calcium pyrophosphate dihydrate). Arthrocentesis should be performed, especially in acute cases. Polarized light microscopy: detection of rhomboid-shaped, positively birefringent CPPD crystals. Synovial fluid findings: 10,000-50,000 WBCs/μL with > 90% neutrophils. X-ray findings: cartilage calcification of the affected joint (chondrocalcinosis). Fibrocartilage (meniscus, annulus fibrosus of intervertebral disc) and hyaline cartilage (joint cartilage) may be affected.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 107
Incorrect
-
In addition to its role in digestion and absorption of fats, bile:
Your Answer: Causes stones
Correct Answer: Is the major excretory route for lipid-soluble waste products
Explanation:The end product of haem metabolism is bilirubin and jaundice is caused by increased bilirubin levels in the blood. Gallstones are mainly caused by cholesterol and bile pigments. Bile is the main route of excretion for lipid soluble waste products whereas urine is the main route of excretion of water soluble waste products.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 108
Correct
-
Endothelial cells are attached to adjacent cells by adherent junctions via:
Your Answer: Cadherins
Explanation:Cadherins are calcium dependant molecules that mediate cell to cell adhesions in epithelial and endothelial cells among others.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 109
Incorrect
-
All of the following are associated with yellow nail syndrome except:
Your Answer: Chronic sinus infections
Correct Answer: Cardiomegaly
Explanation:Yellow nail syndrome is a very rare medical syndrome that includes pleural effusions, lymphedema (due to under development of the lymphatic vessels) and yellow dystrophic nails. Approximately 40% will also have bronchiectasis. It is also associated with chronic sinusitis and persistent coughing and it usually affects adults.
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This question is part of the following fields:
- Dermatology
- Medicine
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Question 110
Incorrect
-
All of the following are Vitamin K-dependent clotting factors except:
Your Answer: Protein S
Correct Answer: Factor XI
Explanation:Activated Vitamin K is used to gamma carboxylate (and thus activate) certain enzymes involved in coagulation: Factors II, VII, IX, X, and protein C and protein S. Inability to activate the clotting cascade via these factors leads to the bleeding symptoms
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This question is part of the following fields:
- Haematology
- Medicine
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Question 111
Incorrect
-
The internodal tract of Bachman:
Your Answer: Its main function is to reduce the amount of conduction to the AV node
Correct Answer: Connects the SA node to the AV node
Explanation:Internodal tract of Bachman connects the SA node to the AV node conducting the electrical impulses generated from the SA node to the AV node and from the AV node to the rest of the electrical complex of the heart.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 112
Incorrect
-
Three adjacent nucleotides code for a particular amino acid. These are called codons. How many common amino acids are there and how many potential codon combinations make up the genetic code?
Your Answer: 12 amino acids, 64 codon combinations
Correct Answer: 20 amino acids, 64 codon combinations
Explanation:There are around 20 amino acids and 61 out of the 64 combinations of codon code for these 20 common amino acids.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 113
Incorrect
-
Alveolar epithelial cells:
Your Answer: Type 2 covers a greater part of the surface
Correct Answer: Type 2 represent 60% of the cells
Explanation:Type I alveolar cells are squamous (giving more surface area to each cell) and cover approximately 90–95% of the alveolar surface. Type I cells are involved in the process of gas exchange between the alveoli and blood. Type II alveolar cells cover a small fraction of the alveolar surface area. Their function is of major importance in the secretion of pulmonary surfactant, which decreases the surface tension within the alveoli. They are also capable of cellular division, giving rise to more type I alveolar cells when the lung tissue is damaged. These cells are granular and roughly cuboidal. Type II alveolar cells are typically found at the blood-air barrier. Although they only comprise <5% of the alveolar surface, they are relatively numerous (60% of alveolar epithelial cells).
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This question is part of the following fields:
- Medicine
- Respiratory
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Question 114
Correct
-
What are the diagnostic criteria for an ST segment elevation type of acute myocardial infarction?
Your Answer: 1 mm ST elevation in 2 limb leads
Explanation:The current guidelines for the ECG diagnosis of the ST segment elevation type of acute myocardial infarction require at least 1 mm (0.1 mV) of ST segment elevation in the limb leads, and at least 2 mm elevation in the precordial leads. These elevations must be present in anatomically contiguous leads. (I, aVL, V5, V6 correspond to the lateral wall; V3-V4 correspond to the anterior wall ; V1-V2 correspond to the septal wall; II, III, aVF correspond to the inferior wall.)
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 115
Correct
-
Depolarization of the T tubule membrane activates the sarcoplasmic reticulum via which receptors?
Your Answer: Dihydropyridine receptors
Explanation:Action potentials are transmitted to the fibrils of a fiber through the T tubule system. It triggers the release of Ca 2+ form the terminal cisterns. Depolarization of the T tubules activates the sarcoplasmic reticulum through the dihydropyridine receptors.
Dihydropyridine receptors (DHPRs), are voltage-gated Ca2+ channels, and ryanodine receptors (RyRs), which are intracellular Ca2+ release channels, are expressed in diverse cell types, including skeletal and cardiac muscle.
Ryanodine receptors (RyRs) are located in the sarcoplasmic/endoplasmic reticulum membrane and are responsible for the release of Ca2+ from intracellular stores during excitation-contraction coupling in both cardiac and skeletal muscle.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 116
Correct
-
A 24-year-old women presents following an overdose. Which one of the following would suggest anticholinergic syndrome?
Your Answer: Mydriasis occurs
Explanation:Anticholinergic syndrome results from the inhibition of muscarinic cholinergic neurotransmission. Clinical manifestations can be remembered by the mnemonic, red as a beet, dry as a bone, blind as a bat, mad as a hatter, hot as a hare, and full as a flask. The mnemonic refers to the symptoms of flushing, dry skin and mucous membranes, mydriasis (dilated pupil) with loss of accommodation, altered mental status, fever, and urinary retention, respectively.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 117
Correct
-
Immortality can result from over expression of which enzyme?
Your Answer: Telomerase
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.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 118
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 119
Incorrect
-
Which hormone secreting cell of the human anterior pituitary gland secretes growth hormone?
Your Answer: Gonadotroph
Correct Answer: Somatotroph
Explanation:Somatotroph cells are responsible for the production of growth hormone. Somatotrophs occupy nearly 40% of the total surface area of the anterior pituitary, and they are acidophilic in nature.
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This question is part of the following fields:
- Endocrinology
- Medicine
-
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Question 120
Correct
-
Which statement about the 2nd heart sound is true?
Your Answer: It is caused by closure of the aortic and pulmonary valves.
Explanation:The second heart sound is produced due to closure of the aortic and pulmonary valves. It is a high pitched dub sound.
Normally the aortic closure sound (A2) occurs prior to the pulmonic closure sound (P2), and the interval between the two (splitting) widens on inspiration and narrows on expiration. With quiet respiration, A2 will normally precede P2 by 0.02 to 0.08 second (mean, 0.03 to 0.04 sec) with inspiration. In younger subjects inspiratory splitting averages 0.04 to 0.05 second during quiet respiration. With expiration, A2 and P2 may be superimposed and are rarely split as much as 0.04 second. If the second sound is split by greater than 0.04 second on expiration, it is usually abnormal. Therefore, the presence of audible splitting during expiration (i.e., the ability to hear two distinct sounds during expiration) is of greater significance at the bedside in identifying underlying cardiac pathology than is the absolute inspiratory increase in the A2–P2 interval.
The respiratory variation of the second heart sound can be categorized as follows: (1) normal (physiologic) splitting; (2) persistent (audible expiratory) splitting, with normal respiratory variation; (3) persistent splitting without respiratory variation (fixed splitting); and (4) reversed (paradoxical) splitting.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 121
Correct
-
Which statement is incorrect?
Your Answer: Translation begins when the triplet (UGA) encoding for methionine is encountered.
Explanation:Translation being when the codon for methionine is encountered which is AUG not UGA. This process is known as initiation. All the other options are correct.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 122
Correct
-
Select the correct statement about the microanatomy of the thyroid gland.
Your Answer: The capillaries adjacent to thyroid cells have a fenestrated endothelium.
Explanation:Fenestrated capillaries have a very thin endothelium, which is perforated by numerous fenestrations or pores. Hormones are usually released into these capillaries, reaching their target cells through the circulatory system.
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This question is part of the following fields:
- Endocrinology
- Medicine
-
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Question 123
Correct
-
Which of the following can trigger parietal cell secretion?
Your Answer: Gastrin
Explanation:The three agonists of parietal cell secretion are gastrin, acetylcholine and histamine. Parietal cells are responsible for the secretion of HCl and intrinsic factor.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
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Question 124
Correct
-
What is the mode of action of bisphosphonates?
Your Answer: Inhibit osteoclasts
Explanation:Bisphosphonates are analogues of pyrophosphate, a molecule which decreases demineralisation in bone. They inhibit osteoclasts by reducing recruitment and promoting apoptosis.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 125
Correct
-
Which statement is correct?
Your Answer: MtDNA principally encodes for proteins that are involved in oxidative phosphorylation for the production of ATP in the cell.
Explanation:Mitochondria have no nucleus instead they contain their own free floating circular genome (MtDNA), which encodes 13 different subunits of proteins involved in oxidative phosphorylation. The remainder of the mitochondrial proteins are nuclear encoded, synthesized in the cytoplasm, and transported into the mitochondria.
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This question is part of the following fields:
- Genetics
- Medicine
-
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Question 126
Incorrect
-
Which neurotransmitter is made from hydroxylation and decarboxylation of tryptophan?
Your Answer: Dopamine
Correct Answer: Serotonin
Explanation:Serotonin is synthesized from the essential amino acid tryptophan. The rate-limiting step is the conversion of the amino acid to 5-hydroxytryptophan by tryptophan hydroxylase. This is then converted to serotonin by the aromatic L-amino acid decarboxylase.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 127
Incorrect
-
Where do the portal hypophysial vessels arise?
Your Answer: Lateral eminence
Correct Answer: Median eminence
Explanation:The hypothalamic-hypophysial portal system connects the brain to the anterior pituitary. It is made up of two capillary beds, one in the median eminence and the other in the anterior pituitary. Blood from the plexus of the median eminence is carried by portal veins, draining into the cavernous and posterior intercavernous sinuses. This system delivers hypothalamic hormones to their target cells.
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This question is part of the following fields:
- Endocrinology
- Medicine
-
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Question 128
Correct
-
Regarding cardiac contractility, catecholamines exert their inotropic effect via:
Your Answer: Β1-adrenergic receptors and gs
Explanation:Catecholamines exert their inotropic effect on the heart via the B1 adrenergic receptors and Gs, stimulating adenyl cyclase and increasing the production of cAMP.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 129
Correct
-
Regarding gustatory sensation:
Your Answer: The sensory taste buds on the anterior two-thirds of the tongue travel to the chorda tympani branch of the facial nerve
Explanation:There are three morphologically distinct types of taste buds including; circumvallate, fungiform and foliate. Circumvallate are rounded structures arranged in a v on the back of the tongue. The posterior third travels to glossopharyngeal nerve.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 130
Incorrect
-
The pyloric sphincter is largely made up of thickening of
Your Answer: Both the oblique and the circular muscle layers
Correct Answer: The circular muscle layer
Explanation:The pyloric sphincter, or valve, is a strong ring of smooth muscle (circular muscle layer) at the end of the pyloric canal which lets food pass from the stomach to the duodenum. It controls the outflow of gastric contents into the duodenum. It receives sympathetic innervation from the celiac ganglion.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
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Question 131
Correct
-
Emulsification of dietary lipids is brought about by
Your Answer: Bile salts
Explanation:Digestion of fats can begin in the mouth where lingual lipase breaks down some short chain lipids into diglycerides. However fats are mainly digested in the small intestine. The presence of fat in the small intestine produces hormones that stimulate the release of pancreatic lipase from the pancreas and bile from the liver which helps in the emulsification of fats for absorption of fatty acids.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
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Question 132
Incorrect
-
The blood supply to the liver is by
Your Answer: Only hepatic portal vein
Correct Answer: Hepatic artery and hepatic portal vein
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 133
Correct
-
Which of the following is not a feature of Liddle’s syndrome?
Your Answer: Autosomal recessive inheritance
Explanation:Liddle’s syndrome is a rare autosomal dominant condition characterized by early, and frequently severe, high blood pressure associated with low plasma renin activity, metabolic alkalosis, low blood potassium, and normal to low levels of aldosterone. Liddle syndrome involves abnormal kidney function, with excess reabsorption of sodium and loss of potassium from the renal tubule, and is treated with a combination of low sodium diet and potassium-sparing diuretic drugs (e.g., amiloride).
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This question is part of the following fields:
- Endocrinology
- Medicine
-
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Question 134
Correct
-
Where is the most erythropoietin produced?
Your 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 135
Incorrect
-
Restriction Enzymes...
Your Answer: Cut RNA 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 136
Incorrect
-
In increasing order of concentration, the main anions in plasma are:
Your Answer: Proteins-, 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 137
Incorrect
-
Which clotting factor is responsible for stabilization of the fibrin clot by formation of covalent cross-linkages?
Your Answer: Factor II
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 138
Correct
-
Which of the following makes up the thick filaments in muscle fibers?
Your Answer: Myosin
Explanation:The thick filaments are made up of myosin and the thin filaments are made up of actin. The thick filaments are twice the size of the thin filaments and are aligned to form the A band. The thin filaments extending out from the A band form the less dense I bands.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 139
Correct
-
Cells responsible for completely renewing the epithelium of the intestine are located:
Your Answer: At the base of the crypts
Explanation:Epithelial cells are renewed every 4-5 days through a process of renewal and migration. Renewal relies on proliferative cells or stem cells that reside at the crypt base of the intestinal glands. Crypts are epithelial invasions into the underlying connective tissue.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
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Question 140
Correct
-
The Sinoatrial node in the majority of people is supplied by the?
Your Answer: Right coronary artery
Explanation:In 60% of people, the SA node is supplied by the right coronary artery branch and in 40% of the people by the left coronary artery.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 141
Incorrect
-
Select one true statement about haemoglobin synthesis…
Your Answer: Produces the tetramer α2ß2 as the end result.
Correct 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
-
-
Question 142
Correct
-
Which of the following structures lie in close proximity to the thyroid?
Your Answer: All of the options
Explanation:The thyroid gland receives its blood supply from the inferior and superior thyroid arteries. The recurrent laryngeal nerves emerges from the superior thoracic outlet bounded in part by the thyroid lobe. Two pairs of parathyroid glands lie near the thyroid. The common carotid artery splits into its external and internal branches at the upper border of the thyroid cartilage; these branches are separated by the gland.
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This question is part of the following fields:
- Endocrinology
- Medicine
-
-
Question 143
Incorrect
-
With regards to the function of the p53 protein produced by the p53 gene, which of the following statements is incorrect?
Your Answer: It triggers apoptosis
Correct Answer: It permits repair of mutations and other defects in RNA
Explanation:The p53 protein is a crucial tumor suppressor and plays several key roles in maintaining cellular integrity:
- Nuclear transcription factor: p53 is a nuclear transcription factor that regulates the expression of various genes involved in cell cycle control, DNA repair, apoptosis, and senescence.
- DNA repair: p53 permits repair of mutations and other defects in DNA (not RNA). It activates the transcription of genes involved in DNA repair mechanisms, allowing the cell to correct errors before proceeding with the cell cycle.
- Cell cycle regulation: p53 can induce the expression of p21, a protein that inhibits cyclin-dependent kinases, thereby halting the cell cycle at the G1/S checkpoint to allow time for DNA repair or to trigger apoptosis if the damage is irreparable. Mutations in p53 may fail to halt the cell cycle, allowing mutations to persist and potentially leading to cancer.
- Apoptosis: If DNA damage is extensive and cannot be repaired, p53 triggers apoptosis to prevent the propagation of damaged cells.
- Suppression of proto-oncogenes: p53 indirectly contributes to the suppression of proto-oncogenes by preventing the proliferation of cells with damaged DNA, thereby reducing the risk of oncogenic transformation.
Given these functions, the statement that p53 “permits repair of mutations and other defects in RNA” is incorrect, as p53 is primarily involved in the repair of DNA, not RNA.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 144
Correct
-
The enzyme responsible for telomeres maintaining their length after cell division is called:
Your Answer: Telomerase
Explanation:Telomerase is the enzyme responsible for maintenance of the length of telomeres by addition of guanine-rich repetitive sequences. Telomerase activity is exhibited in gametes and stem and tumor cells.
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This question is part of the following fields:
- Genetics
- Medicine
-
-
Question 145
Incorrect
-
Which of the following happens when anterograde neurons are stimulated?
Your Answer: Basic electrical rhythm is initiated
Correct Answer: Smooth muscle relaxation ahead of the stimulus
Explanation:Nitric oxide is thought to act as an anterograde neurotransmitter. Nitric oxide causes relaxation of smooth muscles ahead of the stimulus. Clinically it is used as a potent vasodilator.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
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Question 146
Correct
-
The channel that coalesces the small pancreatic duct radicles before joining the common bile duct is known as the:
Your Answer: Duct of Wirsung
Explanation:The small ducts from the pancreas coalesce into a single duct known as the pancreatic duct or the duct of Wirsung. It usually joins the bile duct at the ampulla of Vater before entering the duodenum.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
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Question 147
Correct
-
The following cells replicate without shortening their telomeres because they express telomerase.
Your 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
-
-
Question 148
Correct
-
A 73-year-old female is being reviewed in the osteoporosis clinic. She had a fracture of her left hip 5 years ago and was started on alendronate. Following the development of persistent musculoskeletal pain, alendronate was replaced with risedronate, which was also stopped for similar reasons. Strontium ranelate was therefore started but was also stopped due to the development of deep vein thrombosis in the right leg. Her current T-score is -4.1. A decision is made to start a trial of denosumab. What is the mechanism of action of denosumab?
Your Answer: Inhibits RANK ligand, which in turn inhibits the maturation of osteoclasts
Explanation:The principal mechanism by which strontium inhibits osteoclast activity is by enhancing the secretion of osteoprotegerin (OPG) and by reducing the expression of the receptor activator of nuclear factor κB ligand (RANKL) in osteoblasts.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 149
Incorrect
-
What type of intercellular connection found between cardiac muscle fibers allow for the spread of excitation from one cell to another?
Your Answer: Hemidesmosomes
Correct Answer: Gap junctions
Explanation:The cardiac muscles have gap junctions in-between the cells. They form low resistance passages, which allow ions to diffuse through every muscle fiber rapidly and result in the cardiac muscles functioning as a syncytium, without any protoplasmic bridges involved.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 150
Incorrect
-
What is the effect of oxytocin on the breast?
Your Answer:
Correct Answer: Milk ejection
Explanation:Oxytocin is a peptide hormone and neuropeptide, produced by the hypothalamus and released by the posterior pituitary. It causes the milk ejection or let-down reflex, causing the milk to be transported to the subareolar sinuses, allowing it to be released through the nipple. This response is initiated by the act of suckling by the baby, but it can be conditioned to be triggered by different stimuli.
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This question is part of the following fields:
- Endocrinology
- Medicine
-
SESSION STATS - PERFORMANCE PER SPECIALTY
