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Question 1
Incorrect
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The oesophagus is lined by
Your Answer: Simple columnar epithelium
Correct Answer: Stratified squamous epithelium
Explanation:The wall of the oesophagus from the lumen outwards consists of mucosa, submucosa (connective tissue), layers of muscle fibers between layers of fibrous tissue, and an outer layer of connective tissue. The mucosa is a stratified squamous epithelium of around three layers of squamous cells, which contrasts to the single layer of columnar cells of the stomach. The transition between these two types of epithelium is visible as a zig-zag line. Most of the muscle is smooth muscle although striated muscle predominates in its upper two thirds.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 2
Incorrect
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Psoriatic arthropathy most commonly presents with which of the following types of arthritis?
Your Answer: Arthritis mutilans
Correct Answer: Peripheral asymmetric oligoarthropathy
Explanation:Most patients with psoriatic arthritis present with monoarthritis or asymmetric oligoarthritis. The most common form of the disease is the one involving a few joints of the peripheral skeleton with a distinct asymmetry of symptoms. Involvement of the smaller joints of the hands and feet, especially distal interphalangeal joints, seems to be a characteristic feature. Arthritis mutilans is a rare and severe complication of psoriatic arthritis.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 3
Incorrect
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Which statement is correct?
Your Answer: Mitochondrial DNA has a double helix structure and also has a critical role in apoptosis.
Correct 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 4
Correct
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Question 5
Incorrect
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Male to male transmission is a key factor of which type of inheritance?
Your Answer: X linked recessive
Correct Answer: Autosomal dominant
Explanation:Autosomal dominant type of inheritance can include both sexes in the same ratio. There is no skipping a generation and father to son transmission is common. The passing of the trait is sex independent.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 6
Incorrect
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Which vitamin plays a major role in the metabolism of many amino acids?
Your Answer: Vitamin B3
Correct Answer: Vitamin B6
Explanation:Vitamin B6 is part of the vitamin B group, and its active form, pyridoxal 5′-phosphate (PLP) serves as a coenzyme in many enzyme reactions in amino acid, glucose, and lipid metabolism.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 7
Incorrect
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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
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Question 8
Correct
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The enzyme that catalyses the final step in glycogen synthesis is:
Your Answer: Glycogen synthase
Explanation:Glycogen synthase is a key enzyme in glycogenesis, the conversion of glucose into glycogen. This enzyme combines excess glucose residues one by one into a polymeric chain for storage as glycogen.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 9
Incorrect
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What is the function of secondary messengers?
Your Answer: Communication from intracellular to extracellular signalling pathways
Correct Answer: Communication from extracellular to intracellular signalling pathways
Explanation:First messengers may not physically cross the phospholipid bilayer to initiate changes within the cell directly. This functional limitation necessitates the cell to devise signal transduction mechanisms to transduce first messenger into second messengers, so that the extracellular signal may be propagated intracellularly. Second messengers are intracellular signalling molecules released by the cell to trigger physiological changes such as proliferation, differentiation, migration, survival, and apoptosis. Secondary messengers are therefore one of the initiating components of intracellular signal transduction cascades.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 10
Correct
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The following determines the strength of contraction
Your Answer: Plateau phase
Explanation: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 (or refractory) phase in myocyte action potential 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 11
Incorrect
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In the gastric mucosa, which of the following cells is known to secrete gastric lipase?
Your Answer: Parietal cell
Correct Answer: Chief cell
Explanation:Chief cells produce pepsinogen and gastric lipase. Parietal cells produce stomach acid and intrinsic factor.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 12
Correct
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A 48-year-old male with a history of bipolar disorder presents with acute confusion. In-transit to hospital he had a generalized seizure which terminated spontaneously after around 30 seconds. On arrival to the emergency department, his GCS is 14/15 and he is noted to have a coarse tremor. Suspecting a diagnosis of lithium toxicity, intravenous access is obtained, a blood sample was drawn for investigations and a saline infusion is started. The blood investigations revealed:Lithium level: 4.2 mmol/lNa+: 136 mmol/lK+: 4.6 mmol/lUrea: 8.1 mmol/lCreatinine: 99 µmol/lBicarbonate: 18 mmol/lWhat is the most appropriate management for the patient?
Your Answer: Arrange haemodialysis
Explanation:The presentation of the patient is typical of chronic lithium toxicity (due to the presence of mainly neurological manifestations). Additional to the blood investigations mentioned, urine analysis, electrolyte levels, and renal function should also be performed. A low urine Anion gap and a low urine specific gravity are highly suggestive of lithium toxicity.ECG obtained in this patient is likely to show: nonspecific, diffuse ST segment depression with T wave inversion.Acute lithium toxicity presents with more GI manifestations while, the clinical features of chronic lithium toxicity are mainly neurological and can include:Coarse tremors (fine tremors are seen in therapeutic levels), hyperreflexia, acute confusion, seizures, and coma.The management of lithium toxicity is as follows:Immediate GI decontamination with gastric lavage (in case of acute intoxication)Saline Administrations: the goal of saline administration is to restore GFR, normalize urine output and enhance lithium clearance.Haemodialysis remains the mainstay treatment for lithium toxicity as lithium is readily dialyzed because of water solubility, low volume of distribution, and lack of protein binding.The Extracorporeal Treatments in Poisoning Workgroup (EXTRIP Workgroup) recommendations for dialysis (extracorporeal treatment) in lithium toxicity include:• Impaired kidney function and lithium levels > 4.0 mEq/L• Decreased consciousness, seizures, or life-threatening dysrhythmias, regardless of lithium levels• Levels are > 5.0 mEq/L, significant confusion is noted, or the expected time to reduce levels to < 1.0 mEq/L is more than 36 hoursAs post-dialysis rebound elevations in lithium levels have been documented, continuous veno-venous hemofiltration (CVVH) has been advocated.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 13
Incorrect
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A 50-year-old man with a history of hyperlipidaemia, currently under treatment with simvastatin 10mg was found to have persistently high cholesterol levels. Previous attempts to increase the dose of simvastatin have resulted in myalgia. Given this history, which one of the following lipid-regulating drugs should definitely be avoided?
Your Answer: Ezetimibe
Correct Answer: Bezafibrate
Explanation:Both fibrates and nicotinic acid have been associated with myositis, especially when combined with a statin. However, the Committee on Safety of Medicines has produced guidance which specifically warns about the concomitant prescription of fibrates with statins concerning muscle toxicity.Bezafibrate: It is a fibric acid derivative (fibrate) that has been used as a class of agents known to decrease triglyceride levels while substantially increasing HDL-C levels.Pharmacological effects:- Increases VLDL catabolism by increasing lipoprotein and hepatic triglyceride lipase.- Decreases triglyceride synthesis by inhibiting acetyl-CoA reductase.- Decreases cholesterol synthesis by inhibiting HMG-CoA reductase.Side effects:- Hypersensitivity- Primary biliary cirrhosis- Pre-existing gallbladder disease- Concurrent use with HMG-CoA inhibitors (statins) can produce myopathy- Hepatic/renal impairment in a patient warrants dose adjustment as this drug is primarily excreted via the renal mechanism.Contraindications: Concurrent use of MAO inhibitors, hypersensitivity, pre-existing cholestasis, and pregnancy.Use: It can be used to treat Barth syndrome (characterized by dilated cardiomyopathy, neutropenia (presenting with recurrent infections), skeletal myopathy and short stature)
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 14
Incorrect
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Which of the following values of bone mineral density measured by DEXA would signify osteopenia?
Your Answer: Z score of -2.0
Correct Answer: T score of -2.2
Explanation:DEXA T Scores:Normal T-score ≥ −1.0Osteopenia −2.5 < T-score < −1.0Osteoporosis T-score ≤ −2.5Severe osteoporosis T-score ≤ −2.5 with fragility fracture
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 15
Incorrect
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In the malaria life cycle , parasites which remain dormant in the liver are known as :
Your Answer: Sporozoites
Correct Answer: Hypnozoites
Explanation:The life-cycles of Plasmodium species involve several different stages both in the insect and the vertebrate host. These stages include sporozoites, which are injected by the insect vector into the vertebrate host’s blood. Sporozoites infect the host liver, giving rise to merozoites and (in some species) hypnozoites. These move into the blood where they infect red blood cells. In the red blood cells, the parasites can either form more merozoites to infect more red blood cells, or produce gametocytes which are taken up by insects which feed on the vertebrate host. In the insect host, gametocytes merge to sexually reproduce. After sexual reproduction, parasites grow into new sporozoites, which move to the insect’s salivary glands, from which they can infect a vertebrate host bitten by the insect
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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Question 16
Correct
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Of the daily production of CSF, the vast majority is produced in the:
Your Answer: Choroid plexus
Explanation:About 80% of CSF is produced by the choroid plexus. It is also produced by a single layer of column shaped ependymal cells.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 17
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 18
Correct
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Where is Vitamin B12 mainly stored in the body?
Your Answer: Liver
Explanation:The total amount of vitamin B12 stored in body is about 2–5 mg in adults. Around 50% of this is stored in the liver. Approximately 0.1% of this is lost per day by secretions into the gut, as not all these secretions are reabsorbed.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 19
Incorrect
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According to Starling's law of the heart:
Your Answer: Cardiac output is increased when the sympathetic nerves are stimulated
Correct Answer: The extent of the preload is proportional to the end-diastolic volume
Explanation:Frank starlings law describes that an increase in the venous return or the end diastolic volume will cause an increase in the stroke volume/ preload and also cardiac output. It stems from the fact that increased venous return will increase the stretch on the ventricular muscle fibers. The sarcomere will stretch a considerable length that is needed for maximum contraction and the development of tension in the muscle fiber. The greater the venous return the greater the cardiac output. This relationship is directly proportional.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 20
Incorrect
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Which clotting factor is responsible for stabilization of the fibrin clot by formation of covalent cross-linkages?
Your Answer: Factor VIII
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 21
Correct
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Which of the following is not a cause of drug-induced hepatitis?
Your Answer: Ethambutol
Explanation:Although rare, ocular toxicity in the form of optic neuritis (most commonly retrobulbar neuritis) has been well documented as a side effect of ethambutol. It is renally excreted and not associated with hepatitis.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 22
Incorrect
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Neurons that are inactive during quiet breathing, become active when the respiratory drive for increased ventilation becomes greater than normal. These are located in the:
Your Answer: Dorsal respiratory group
Correct Answer: Ventral respiratory group
Explanation:The mechanism of control of ventilation is an interplay of multiple regions in the brain. Medullary respiratory centre sets the basic rhythm of breathing. The dorsal respiratory group integrates input from the stretch receptors and the chemoreceptors in the periphery and is composed mainly of inspiratory neurons which controls the basic rhythm of breathing. The ventral respiratory group generates breathing rhythm and integrates data coming in to the medulla. It 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 23
Incorrect
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Where is the aqueous humor normally reabsorbed?
Your Answer: Ciliary body
Correct Answer: Canal of schlemm
Explanation:Aqueous humor is a clear protein free fluid secreted by the ciliary body, it travels to the anterior chamber through the pupil and is absorbed through a network of trabeculae into the canal of schlemm
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This question is part of the following fields:
- Medicine
- Neurology
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Question 24
Correct
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Choose the correct statement. The cells of the liver…
Your Answer: Help to maintain the normal blood glucose level.
Explanation:Synthesis of vitamin D3 takes place in both the liver and in the kidneys. The liver is responsible for an intermediate step and final synthesis takes place in the kidneys. Immunoglobulins are manufactured by plasma cells in respective organs where there is antigen exposure. The liver plays a major role in maintaining blood glucose levels by converting excess glucose to glycogen and converting glycogen back to glucose in time of need. Hepatocytes have enzymes that can deactivate steroid hormones.
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This question is part of the following fields:
- Hepatobiliary
- Medicine
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Question 25
Correct
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A 22-year-old female comes to you for counselling regarding the initiation of combined oral contraceptive pill. Which of the following statements is correct?
Your Answer: She will still be protected against pregnancy if she takes amoxicillin for a lower respiratory tract infection while on the combined pill
Explanation:The true statement among the given options is that she will still be protected against pregnancy if she takes amoxicillin for a lower respiratory tract infection while on the combined pill.Other than enzyme-inducing antibiotics such as rifampicin, antibiotics do not reduce the efficacy of the combined oral contraceptive pill.It was previously advised that barrier methods of contraception should be used if taking an antibiotic while using the contraceptive pill, due to concerns that antibiotics might reduce the absorption of the pill. This is now known to be untrue. However, if the absorptive ability of the gut is compromised for another reason, such as severe diarrhoea or vomiting, or bowel disease, this may affect the efficacy of the pill.The exception to the antibiotic rule is that hepatic enzyme-inducing antibiotics such as rifampicin and rifaximin do reduce the efficacy of the pill. Other enzyme-inducing drugs, such as phenytoin, phenobarbital, carbamazepine or St John’s Wort can also reduce the effectiveness of the pill.Other options:The combined pill is often prescribed for women with heavy periods as it can make them lighter and less painful. There is no evidence that women on the combined pill put on any significant weight, although they may experience bloating at certain times in the course. Women on the pill require monitoring of their blood pressure. There are multiple different types of combined pills.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 26
Incorrect
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A 51-year-old real estate agent takes hydrocortisone 20mg in the mornings and 5mg at night for Addison’s disease. The endocrinology consultant would like her to take prednisolone instead. What dose of prednisolone should be started?
Your Answer: 5 mg
Correct Answer: 7 mg
Explanation:1mg Prednisolone = 4mg hydrocortisone, so the actual equivalent daily dose is 7mg.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 27
Incorrect
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Coronary vasoconstriction can be caused by:
Your Answer: Hypoxia
Correct Answer: Beta blockage
Explanation:Coronary arteries contain alpha and beta receptors. The alpha receptor stimulates vasoconstriction and beta receptors stimulate vasodilation. When the chronotropic and inotropic effects of noradrenergic receptors are blocked by a B blocking drug, stimulation of the noradrenergic nerves will cause coronary vasoconstriction.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 28
Incorrect
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Where does secretin work in the pancreas?
Your Answer: Beta cells
Correct Answer: Pancreatic ducts
Explanation:Secretin, a hormone produced by the duodenal S cells in response to the stomach chyme containing high hydrogen atom concentration (high acidity), is released into the blood stream; upon return to the digestive tract, secretion decreases gastric emptying, increases secretion of the pancreatic ductal cells, as well as stimulating pancreatic acinar cells to release their zymogenic juice.
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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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There will be a proportion of people in a population who have the given condition, disease or attribute at a specified point in time or over a specified period of time. Which of following is the best term which can describe the above?
Your Answer: Prevalence
Explanation:Prevalence refers to the total number of cases of a particular disease or condition present in a population at a specific point in time or over a specified period. It provides a measure of how widespread the disease or condition is within the population.
Specificity and sensitivity are terms used to describe the accuracy of diagnostic tests.
Probability refers to the likelihood of an event occurring.
Incidence is a measure of how commonly or frequently a disease occurs in a specified population over a period by providing a quick measurement of new disease diagnoses.
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This question is part of the following fields:
- Medicine
- Research Skills
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Question 30
Correct
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The posterior aspect of the interventricular septum is supplied by:
Your Answer: A branch of the right coronary artery
Explanation:The posterior aspect of the heart is supplied by the posterior interventricular artery which is a branch of the right coronary artery.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 31
Correct
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Question 32
Incorrect
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Which of the following factors serve to decrease cardiac output?
Your Answer: Increased ambient temperature
Correct Answer: Standing from a lying position
Explanation:Sleep has no effect on the cardiac output. Anxiety, excitement, increased body temperature and pregnancy will increase the cardiac output. Standing from a lying position will decrease the cardiac output transiently.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 33
Incorrect
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What are the major motor proteins that interact with microtubules?
Your Answer: Keratin and dynein
Correct Answer: Kinesin and dynein
Explanation:The major motor proteins that interact with microtubules are kinesin, which usually moves toward the (+) end of the microtubule, and dynein, which moves toward the (−) end.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 34
Correct
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Which dorsal (sensory) root is responsible for umbilical area sensation?
Your Answer: T10
Explanation:The area of skin supplied by one nerve is called a dermatome. T10 supplies sensory neurons to the area of the umbilicus. C3 and C4 supply the neck and the shoulder, T4 supplies the dermatome at the level of the nipple, S3 supplies the inguinal region and L5 supplies the lateral aspect of the leg and the medical aspect of the dorsum of the feet plus the first 3 toes.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 35
Correct
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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 36
Correct
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On a mountain the atmospheric pressure is 700 mmHg and the humidity close to zero, the partial pressure of oxygen is:
Your Answer: 147 mmHg
Explanation:Natural air includes approximately 21% of oxygen. If humidity is zero, the partial pressure of oxygen is 700 × 21% = 147 mmHg
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This question is part of the following fields:
- Medicine
- Respiratory
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Question 37
Incorrect
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A 35 year old female, known case of anti phospholipid syndrome, arrives at the clinic due to a swollen and painful left leg. Doppler ultrasonography confirms the diagnosis of a deep vein thrombosis. She was previously diagnosed with DVT 4 months back and was on warfarin therapy (target INR 2-3) when it occurred. How should her anticoagulation be managed?
Your Answer: Life-long warfarin, target INR 2 - 3
Correct Answer: Life-long warfarin, increase target INR to 3 - 4
Explanation:If the INR in the range of 2-3 has still resulted in thrombosis, the target INR is increased to 3-4. However, because the risk of bleeding increases as the INR rises, the INR is closely monitored and adjustments are made as needed to maintain the INR within the target range.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 38
Correct
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The principle by which the energy of contraction is proportional to the initial length of cardiac muscle fiber is known as:
Your Answer: Starling’s law
Explanation:The Frank starling relationship describes that an increase in the venous return or the end diastolic volume will cause an increase in the stroke volume/ preload and also cardiac output. It stems from the fact that increase venous return will increase the stretch on the ventricular muscle fibers. The sarcomere will stretch a considerable length that is needed for maximum contraction and increased development of tension in the muscle fiber. The greater the venous return the greater the cardiac output. This relation is directly proportional.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 39
Incorrect
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The cerebellum consist of which three lobes?
Your Answer: Medial, lateral and flocculonodular
Correct Answer: Anterior, posterior and flocculonodular
Explanation:The cerebellum consists of 3 lobes; Anterior, Posterior and Flocculonodular lobe.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 40
Correct
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A 30-year-old female was brought to the ER in a confused state. The patient works in a photograph development laboratory. On admission, she was hypoxic and hypotensive. A provisional diagnosis of cyanide poisoning was made. What is the definitive treatment?
Your Answer: Hydroxocobalamin
Explanation:Cyanide poisoning: Aetiology:Smoke inhalation, suicidal ingestion, and industrial exposure (specific industrial processes involving cyanide include metal cleaning, reclaiming, or hardening; fumigation; electroplating; and photo processing) are the most frequent sources of cyanide poisoning. Treatment with sodium nitroprusside or long-term consumption of cyanide-containing foods is a possible source.Cyanide exposure most often occurs via inhalation or ingestion, but liquid cyanide can be absorbed through the skin or eyes. Once absorbed, cyanide enters the blood stream and is distributed rapidly to all organs and tissues in the body. Pathophysiology:Inside cells, cyanide attaches itself to ubiquitous metalloenzymes, rendering them inactive. Its principal toxicity results from inactivation of cytochrome oxidase (at cytochrome a3), thus uncoupling mitochondrial oxidative phosphorylation and inhibiting cellular respiration, even in the presence of adequate oxygen stores.Presentation:• ‘Classical’ features: brick-red skin, smell of bitter almonds• Acute: hypoxia, hypotension, headache, confusion• Chronic: ataxia, peripheral neuropathy, dermatitisManagement:• Supportive measures: 100% oxygen, ventilatory assistance in the form of intubation if required.• Definitive: Hydroxocobalamin (iv) is considered the drug of choice and is approved by the FDA for treating known or suspected cyanide poisoning. • Coadministration of sodium thiosulfate (through a separate line or sequentially) has been suggested to have a synergistic effect on detoxification.Mechanism of action of hydroxocobalamin: • Hydroxocobalamin combines with cyanide to form cyanocobalamin (vitamin B-12), which is renally cleared.• Alternatively, cyanocobalamin may dissociate from cyanide at a slow enough rate to allow for cyanide detoxification by the mitochondrial enzyme rhodanese.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 41
Correct
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Which immunological cells are predominant in the lymph node (almost 98 % residence)?
Your Answer: Lymphocytes
Explanation:Lymph nodes are a lymphoid organ mostly consisting of lymphocytes: B cells in the cortex from where they mature and proliferate and T cells in the paracortex. The medulla is also composed of lymphocytes and macrophages.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 42
Correct
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In the presence of oxygen , lactate that was produced under anaerobic conditions is converted to:
Your Answer: Pyruvate
Explanation:Lactate can be used in two ways:Oxidation back to pyruvate by well-oxygenated muscle cells, heart cells, and brain cells. Pyruvate is then directly used to fuel the Krebs cycle orConversion to glucose via gluconeogenesis in the liver and release back into circulation.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 43
Incorrect
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What effect does osmotic diuresis have on net Na+ excretion?
Your Answer: No net effect
Correct Answer: Markedly increased Na+ excretionÂ
Explanation:Osmotic diuresis is the increase of urination rate caused by the presence of certain substances in the small tubes of the kidneys. The excretion occurs when substances such as glucose enter the kidney tubules and cannot be reabsorbed (due to a pathological state or the normal nature of the substance). The substances cause an increase in the osmotic pressure within the tubule, causing retention of water within the lumen, and thus reduces the reabsorption of water, increasing urine output (i.e. diuresis). Sodium, chloride, potassium are markedly excreted in osmotic diuresis.
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This question is part of the following fields:
- Medicine
- Renal
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Question 44
Correct
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Carotid bodies...
Your Answer: Are located near the bifurcation of the carotid arteries bilaterally
Explanation:The carotid body is a small cluster of chemoreceptors and supporting cells located near the fork (bifurcation) of the carotid artery (which runs along both sides of the throat).The carotid body detects changes in the composition of arterial blood flowing through it, mainly the partial pressure of oxygen, but also of carbon dioxide. Furthermore, it is also sensitive to changes in pH and temperature. Carotid bodies trigger an action potential through the afferent fibers of the glossopharyngeal nerve,
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This question is part of the following fields:
- Medicine
- Respiratory
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Question 45
Correct
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A cohort study is developed to assess the correlation between blood pressure and working long hours. After 10 years of follow-up and for the 1050 individuals working less than 40 hours per week, 1000 patients had normal blood pressure and 50 patients were diagnosed with hypertension. For the 660 patients working more than 40 hours per week, 600 patients had normal blood pressure and 60 patients were diagnosed with hypertension. If you work more than 40 hours per week, what is the odds ratio of developing hypertension compared to the individuals working less than 40 hours per week?
Your Answer: 2
Explanation:An odds ratio (OR) is a measure of the association between an exposure and an outcome. The OR represents the odds that an outcome will occur given a particular exposure, compared to the odds of the outcome occurring in the absence of that exposure. Odds ratios are most commonly used in case-control studies, however they can also be used in cross-sectional and cohort study designs as well (with some modifications and/or assumptions). Wherea = Number of exposed casesb = Number of exposed non-casesc = Number of unexposed casesd = Number of unexposed non-casesOR=(a/c) / (b/d) = ad/bc
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This question is part of the following fields:
- Medicine
- Research Skills
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Question 46
Correct
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An obstruction in a pulmonary artery causes impaired perfusion to an area in the lung. The gas values in the unperfused alveoli at sea level will be:
Your Answer: PO2 = 149 C02 =0
Explanation:Partial pressure of oxygen at sea level is approximately 160 mmHg. Partial pressure of oxygen in alveoli is around 150 mmHg and in an arteriole is around 80-100 mmHg. Partial pressure of carbon dioxide is around 35 mmHg in alveolar air and around 40 mmHg in the arteriole.
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This question is part of the following fields:
- Medicine
- Respiratory
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Question 47
Correct
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A 65-year-old man, after suffering from a pathological rib fracture, complains of recurrent infection. Bone marrow aspiration revealed a calcium level of 3.9 mmol/l and alkaline phosphatase level of 160u/l. What type of cell would be found in abundance in the marrow spear?
Your Answer: Plasma cells
Explanation:Multiple myeloma or plasma cell myeloma, is a cancer of plasma cells, responsible for producing antibodies. It often, presents early with no symptoms followed by bone pain and pathological fractures (metastases), raised calcium levels, bleeding, frequent infections, and anaemia. It usually occurs around the age of 61 and is more common in men than women.
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This question is part of the following fields:
- Geriatrics
- Medicine
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Question 48
Correct
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Critical shortening of Telomeres result in:
Your Answer: Activation of p53 and prb and cell crisis
Explanation:Telomeres are repetitive nucleotide sequences at the ends of chromosomes that protect them from deterioration or from fusion with neighboring chromosomes. Each time a cell divides, its telomeres shorten. When they become critically short, they can no longer protect the chromosome ends, triggering a DNA damage response.
This response leads to the activation of tumor suppressor proteins p53 and pRb (retinoblastoma protein). Activated p53 can induce cell cycle arrest, allowing time for DNA repair or triggering apoptosis if the damage is irreparable. Similarly, pRb helps regulate cell cycle progression and can halt the cell cycle to prevent the proliferation of cells with damaged DNA.
As a result, the cell enters a state of crisis, characterized by widespread cell death and genomic instability, which ultimately prevents the propagation of cells with critically shortened telomeres.
Therefore, the correct answer is:
Activation of p53 and pRb and cell crisis
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This question is part of the following fields:
- Genetics
- Medicine
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Question 49
Correct
-
Which of the following substances inhibits pancreatic secretion?
Your 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
-
Bile salts are responsible for:
Your Answer: The emulsification of fats
Explanation:The main function of bile acids is to allow digestion of dietary fats and oils by acting as a surfactant that emulsifies them into micelles, allowing them to be colloidally suspended in the chyme before further processing.
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This question is part of the following fields:
- Hepatobiliary
- Medicine
-
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Question 51
Incorrect
-
Question 52
Incorrect
-
Which of the following stimulates glucagon release?
Your Answer: Glucose
Correct Answer: Exercise
Explanation:Studies have shown a small increase in glucagon levels during stress tests and exercise. This occurs in response to the reduction of blood glucose levels during physical activity; epinephrine levels are also a stimulus for the release of glucagon during exercise, since it suppresses insulin, which accounts for its stimulatory effects on glucagon. The use of stored fats for energy during exercise also stimulates the release of glucagon.
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This question is part of the following fields:
- Endocrinology
- Medicine
-
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Question 53
Correct
-
Which of the following drugs would be the safest to prescribe in a 22 year old man with seropositive rheumatoid arthritis who is planning to start a family?
Your Answer: Prednisolone
Explanation:Prednisolone although has many undesirable side effects it may be considered relatively safe compared to the drugs that are provided here. Prolonged treatment with sulphasalazine may depress semen quality and cause irreversible infertility. Methotrexate and leflunomide both inhibit purine/pyrimidine synthesis (the former by inhibiting folate metabolism) and are contraindicated in pregnancy or while trying to conceive. In males, a temporary or permanent decrease in sperm count may occur with cyclophosphamide. Because the recovery of fertility after cyclophosphamide therapy is variable, sperm banking should be considered before treatment is begun.
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This question is part of the following fields:
- Connective Tissue
- Medicine
-
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Question 54
Correct
-
Cholesterol is synthesized in all of these organs EXCEPT?
Your Answer: Stomach
Explanation:The liver primarily synthesizes about 20-25% of the total daily cholesterol. Cholesterol is also synthesized to smaller extents in the adrenal glands, reproductive organs (as cholesterol is the precursor of sex hormones), skin and is also produced in the intestines.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
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Question 55
Incorrect
-
Question 56
Incorrect
-
A 47-year-old woman diagnosed with oestrogen receptor positive breast cancer three months ago was started on treatment with tamoxifen. Which of the following is most likely a complaint of this patient during her review today?
Your Answer: Cataracts
Correct Answer: Hot flushes
Explanation:The most likely complaint of this patient would be hot flushes.
Alopecia and cataracts are listed as possible side-effects, however they are not as prevalent as hot flushes, which are very common in pre-menopausal women.
Tamoxifen is a Selective Oestrogen Receptor Modulator (SERM) which acts as an oestrogen receptor antagonist and partial agonist. It is used in the management of oestrogen receptor-positive breast cancer
Adverse effects:
- Menstrual disturbance: vaginal bleeding, amenorrhoea
- Hot flushes – 3% of patients stop taking tamoxifen due to climacteric side-effects.
- Venous thromboembolism.
- Endometrial cancer (although antagonistic with respects to breast tissue, tamoxifen may serve as an agonist at other sites. Therefore the risk of endometrial cancer is increased). Raloxifene is a pure oestrogen receptor antagonist and carries a lower risk of endometrial cancer.
Tamoxifen is typically used for 5 years following the removal of the tumour.
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This question is part of the following fields:
- Medicine
- Pharmacology
-
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Question 57
Correct
-
The outer and inner surfaces of the arachnoid mater is covered with:
Your Answer: Mesothelial cells
Explanation:The arachnoid mater is one of the three meninges that covers the brain and spinal cord. It is interposed between the two other meninges, the more superficial and much thicker dura mater and the deeper pia mater, from which it is separated by the subarachnoid space. The arachnoid mater consists of a subdural mesothelial layer and a compact central layer
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This question is part of the following fields:
- Medicine
- Neurology
-
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Question 58
Incorrect
-
Dietary starch is mainly:
Your Answer: Amylose
Correct Answer: Amylopectin
Explanation:Dietary starch consists of two types of molecules: the linear and helical amylose and the branched amylopectin. Starch generally contains 20 to 25% amylose and 75 to 80% amylopectin by weight but depends in the plant. Glycogen, the glucose store of animals, is a more branched version of amylopectin.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 59
Incorrect
-
What is the effect of catecholamines (i.e. increased heart rate) on the pressure volume loop?
Your Answer: No effect
Correct Answer: Shifts the diastolic pressure curve upward and leftward
Explanation:Catecholamines have a positive ionotropic and chronotropic effect on the heart. The ventricles develop greater tension during systole resulting in an increase in the stroke volume. The increase in stroke volume results in a decrease in the end diastolic volume. This pushes the loop towards the left and upwards.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 60
Incorrect
-
Which of the following is NOT a pancreatic enzyme?
Your Answer: Colipase
Correct 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
-
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Question 61
Incorrect
-
Which ion channel does not contribute to the myocardial action potential?
Your Answer: Transient outward potassium channel
Correct Answer: Chloride channel
Explanation:The upstroke in the cardiac action potential is due to opening of the sodium channels and an influx of sodium into the cell. The initial repolarization phase is due to transient opening of the potassium channels along with calcium channels. Influx of calcium causes the prolonged plateau phase of the action potential. Delayed opening of the rectifier potassium channel and delayed closure of the calcium channel leads to the repolarization phase of cardiac action potential.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 62
Incorrect
-
The production of bile is increased by: Stimulation of the ____ nerve and the hormone ____.
Your Answer: Vagus, secretin
Correct Answer: Vagus, CCK
Explanation:Cholecystokinin is synthesized and secreted by enteroendocrine cells in the duodenum, the first segment of the small intestine, and causes the release of digestive enzymes and bile from the pancreas and gallbladder, respectively. It also acts as a hunger suppressant. Release of CCK is stimulated by monitor peptide released by pancreatic acinar cells as well as CCK-releasing protein, a paracrine factor secreted by enterocytes in the gastrointestinal mucosa. In addition, release of acetylcholine by the parasympathetic nerve fibers of the vagus nerve also stimulate its secretion.
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This question is part of the following fields:
- Hepatobiliary
- Medicine
-
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Question 63
Correct
-
Habituation…
Your Answer: Is a simple form of learning in which a neutral stimulus is repeated many times
Explanation:It is a simple form of learning where an organism decreases or ceases it’s response to a certain stimuli after repeated presentation. The organisms learns to stop responding to a stimulus which is no longer biologically relevant.
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This question is part of the following fields:
- Medicine
- Neurology
-
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Question 64
Incorrect
-
Question 65
Incorrect
-
Acetylcholine from enteric nerve endings stimulates this pair:
Your Answer: Ecl cells and surface mucus cells
Correct Answer: Parietal cells and chief cells
Explanation:In the body of the stomach, the vagal postganglionic muscarinic nerves release acetylcholine(ACh) which stimulates parietal cell H+ secretion. Gastric chief cells are primarily activated by ACh. However the decrease in pH caused by activation of parietal cells further activates gastric chief cells.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 66
Incorrect
-
Which protein in the HIV genome is responsible for binding to the host CD4 cells?
Your Answer: p17
Correct Answer: gp120
Explanation:HIV can infect a variety of immune cells such as CD4+ T cells, macrophages, and microglial cells. HIV-1 entry to macrophages and CD4+ T cells is mediated through interaction of the virion envelope glycoproteins (gp120) with the CD4 molecule on the target cells and also with chemokine coreceptors.
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This question is part of the following fields:
- Infectious Diseases
- Medicine
-
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Question 67
Incorrect
-
A 33-year-old electrical technician presents following an overdose. Anticholinergic syndrome is suspected. Which of the following is true?
Your Answer: Tricyclic antidepressants are not a cause
Correct Answer: Mydriasis occurs
Explanation:Anticholinergic syndrome occurs following overdose with drugs that have prominent anticholinergic activity including tricyclic antidepressants, antihistamines and atropine. Features include dry, warm, flushed skin, urinary retention, tachycardia, mydriasis (dilated pupils) and agitation.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 68
Incorrect
-
A 71-year-old woman residing in a nursing home for a couple of years complains of drooling of saliva and sudden difficulty in swallowing while eating. She is a known hypertensive on treatment. What would be your next step?
Your Answer: Laryngoscopy
Correct Answer: Endoscopy
Explanation:Dysphagia or difficulty in swallowing. Endoscopy allows for visual examination of the oesophagus and is indicated in patients with dysphagia to determine the underlying aetiology, exclude malignant and premalignant conditions, assess the need for therapy, and perform therapy including dilation.
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This question is part of the following fields:
- Geriatrics
- Medicine
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Question 69
Correct
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Question 70
Incorrect
-
Why does arterial blood pressure drop during pregnancy?
Your Answer: The enlarged uterus leads to inferior vena cava compression
Correct Answer: Progesterone relaxes vascular smooth muscle
Explanation:Progesterone relaxes vascular smooth muscle thus resulting In a decrease in total peripheral resistance. This accounts for the increase in the cardiac output.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 71
Incorrect
-
Which of the following is a form of synaptic plasticity?
Your Answer: Long term depression
Correct Answer: Working memory
Explanation:Synaptic plasticity is an important neurochemical foundation of working memory and generation of memory. Synaptic plasticity is the ability of synapses to strengthen or weaken over time in response to increases or decreases in their activity.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 72
Correct
-
Currents caused by opening of which of the following channels contribute to the repolarization phase of the action potential of the ventricular muscle fibers?
Your Answer: Potassium channels
Explanation:Depolarization occurs due to opening of the voltage gated sodium channels. Repolarization occurs due to opening of the voltage gates potassium channels causing an out flux of potassium ions, decreasing the membrane potential towards resting potential.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 73
Incorrect
-
The hepatic plates in the liver parenchyma consist of how many cell layers?
Your Answer: More than a hundred cell layers
Correct Answer: 1 – 2 cell layers
Explanation:Hepatic plates in a hepatic lobule are arranged in 1-2 cell layers.
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This question is part of the following fields:
- Hepatobiliary
- Medicine
-
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Question 74
Correct
-
Absorption of protein antigens i.e. bacterial and viral proteins takes place in the:
Your Answer: Microfold cells (m cells) of the intestine
Explanation:M cells are specialized epithelial cells. They have a high capacity of transcytosis of microorganisms and macromolecules. They rapidly uptake antigens and present them to immune cells associated with the gut. In contrast to absorptive enterocytes, M cells do not exert direct defence mechanisms to antigens and pathogens in the intestinal cavity. Crypts of Lieberkühn are located mainly in the small intestine and large intestine and the main function is to replenish epithelial cells and to secrete intestinal enzymatic juice as well as mucous. Brunner’s glands empty into intestinal glands and their main function is to secrete mucin and to form a protective mucus layer on the duodenal epithelial cells to protect it from acidic chyme coming from the stomach. Islets of Langerhans are located in the pancreas and secrets insulin mainly. Mucosa associated lymphoid tissue plays a role in inducing immune response after presentation of antigens.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 75
Incorrect
-
A 68 year old male, previously diagnosed with osteoarthritis presents to your clinic with acute on chronic pain in his big toe. Past history is significant for hypertension for which he takes Bendroflumethiazide 5mg daily. Examination reveals an erythematous, red hot metatarsophalangeal joint that has a knobbly appearance. X-ray shows punched out bony cysts. Which of the following would be the most appropriate long term management for this patient?
Your Answer: Start flucloxacillin
Correct Answer: Stop Bendroflumethiazide and substitute a calcium antagonist
Explanation:The most likely diagnosis is chronic tophaceous gout, which is classically associated with chronic renal impairment or long term diuretic therapy. There is tophus formation due to urate crystal deposition in and around the joint. These tophi can also form in the bones and soft tissues. Renal manifestations with uric acid include nephrolithiasis and uric acid nephropathy. Whenever there is an acute on chronic attack of gout, the inciting cause must be established and in case of diuretic use, they should be immediately replaced with another medication. Allopurinol is never started during an acute episode. it is first allowed to settle before administration of allopurinol. Although dietary restriction must be observed in people with a propensity of gout, this scenario clearly presents diuretics as the cause.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 76
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
-
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Question 77
Incorrect
-
Which of the following concerning PR interval is INCORRECT?
Your Answer: The normal duration is 0.12-0.20s
Correct Answer: Always measured from the beginning of p wave to the beginning of r wave
Explanation:The PR interval measures the time from the start of atrial depolarization to the start of ventricular depolarization. The PR interval is only measured from the beginning of P wave to beginning of R wave if the Q wave is absent.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 78
Incorrect
-
The AV Node:
Your Answer: It is a complex spindle shaped structure located in the interventricular septum
Correct Answer: It decelerates impulses passing to the ventricles
Explanation:The action potentials in the sinoatrial (SA) and atrioventricular (AV) nodes are largely due to Ca2+, with no contribution by Na+ influx. The depolarization continues to conduct slowly through the atrioventricular (AV) node. The AV node is located in the right posterior portion of the interatrial septum. This is small and bean-shaped. The atrial conductive system is organized so that the cardiac impulse does not travel from the atria into the ventricles too rapidly; this delay allows the atria to empty before ventricular contraction begins. It is the AV node and its adjacent conductive fibers that delay this transmission into the ventricles. Conduction through the AV Node is represented on the ECG by the PR interval.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 79
Incorrect
-
Where does the pituitary gland lie?
Your Answer: Around the 4th ventricle
Correct Answer: In a pocket of the sphenoid bone at the base of the brain
Explanation:The pituitary lies in a small depression in the sphenoid bone, known as the sella turcica or Turkish saddle.
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This question is part of the following fields:
- Endocrinology
- Medicine
-
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Question 80
Incorrect
-
Medullary chemoreceptors
Your Answer: Monitor PCO2 concentration of arterial blood
Correct Answer: Monitor H+ concentration of the CSF
Explanation:Central chemoreceptors of the central nervous system, located on the ventrolateral medullary surface in the vicinity of the exit of the 9th and 10th cranial nerves, are sensitive to the pH of their environment. These act to detect the changes in pH of nearby cerebral spinal fluid (CSF) that are indicative of altered oxygen or carbon dioxide concentrations available to brain tissues.
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This question is part of the following fields:
- Medicine
- Respiratory
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Question 81
Incorrect
-
Which part of the cerebellum is primarily responsible for interacting with the motor cortex and planning and programming movements?
Your Answer: Spinocerebellum
Correct Answer: Cerebrocerebellum
Explanation:The cerebrocerebellum is the largest functional subdivision of the cerebellum, comprising of the lateral hemispheres and the dentate nuclei. It is involved in the planning and timing of movements, and in the cognitive functions of the cerebellum.
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This question is part of the following fields:
- Medicine
- Neurology
-
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Question 82
Incorrect
-
A 60-year-old male is under treatment with azathioprine after a renal transplant. During his review, he complains of pain and swelling over his left great toe. Investigations reveal hyperuricemia. Suspecting gout, he was started on allopurinol. Subsequently, he develops aplastic anaemia. Which of the following is the most appropriate reason for his bone marrow failure?
Your Answer: Allopurinol toxicity
Correct Answer: Mercaptopurine toxicity
Explanation:The cause for bone marrow suppression in this patient is most probably mercaptopurine toxicity.Azathioprine is metabolized to 6-mercaptopurine (6-MP), which itself is metabolized by xanthine oxidase. Xanthine oxidase inhibition by allopurinol leads to the accumulation of 6-MP which then precipitates bone marrow failure. This may be potentially fatal if unrecognized.Clinical presentation:Toxicity symptoms include gastrointestinal symptoms, bradycardia, hepatotoxicity, myelosuppression.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 83
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 2.5 mg orally
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
-
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Question 84
Incorrect
-
Where is intrinsic factor secreted?
Your Answer: Proximal ileum
Correct Answer: Gastric parietal cells
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:
- Haematology
- Medicine
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Question 85
Incorrect
-
Which one of the following makes up most of the adrenal cortex?
Your Answer: Zona reticularis
Correct Answer: Zona fasciculata
Explanation:The zona fasciculata represents the widest area of the adrenal cortex, situated in the middle of the cortex. It produces glucocorticoids including; 11-deoxycorticosterone, corticosterone, and cortisol.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 86
Correct
-
What is the function of the macula densa, located in the wall of the thick ascending limb?
Your Answer: Tubuloglomerular feedback.
Explanation:Macula densa cells sense changes in sodium chloride level, and will trigger an autoregulatory response to increase or decrease reabsorption of ions and water to the blood (as needed) in order to alter blood volume and return blood pressure to normal. Tubuloglomerular feedback is one of several mechanisms the kidney uses to regulate glomerular filtration rate (GFR). It involves the concept of purinergic signalling, in which an increased distal tubular sodium chloride concentration causes a basolateral release of adenosine from the macula densa cells. This initiates a cascade of events that ultimately brings GFR to an appropriate level.
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This question is part of the following fields:
- Medicine
- Renal
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Question 87
Incorrect
-
The postextrasystolic potentiation of myocardial contractility is due to:
Your Answer: Increase in cardiac rate
Correct Answer: Increase in intracellular Ca2+
Explanation:The postextrasystolic potentiation of myocardial contractility Is not due to ventricular filling. It occurs in isolated locations in the heart and is due to increase availability of intracellular calcium.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 88
Incorrect
-
At rest, proton pumps are sequestered within the parietal cell in a series of membrane compartments known as:
Your Answer: Golgi apparatus
Correct 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 89
Incorrect
-
Select a factor which stimulates glucagon secretion.
Your Answer: Insulin
Correct Answer: Protein meal
Explanation:Several studies have shown that glucagon levels are increased in individuals with a high protein diet. It is still debated, however, whether this type of diet affects insulin levels as well.
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This question is part of the following fields:
- Endocrinology
- Medicine
-
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Question 90
Incorrect
-
What is the most common cause of primary hyperaldosteronism?
Your Answer: Adrenocortical adenoma
Correct Answer: Bilateral idiopathic adrenal hyperplasia
Explanation:Primary aldosteronism, also known as primary hyperaldosteronism or Conn’s syndrome, is excess production of the hormone aldosterone by the adrenal glands resulting in low renin levels. Primary hyperaldosteronism has a number of causes. About 66% of cases are due to enlargement of both adrenal glands and 33% of cases are due to an adrenal adenoma that produces aldosterone. Other uncommon causes include adrenal cancer and an inherited disorder called familial hyperaldosteronism
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This question is part of the following fields:
- Endocrinology
- Medicine
-
-
Question 91
Incorrect
-
Which cells secrete insulin?
Your Answer: A cells of the islets of Langerhans
Correct Answer: B cells of the pancreatic islets
Explanation:Insulin is synthesised and stored by the B cells of the pancreatic islets (70% of islet cells), glucagon is synthesised and stored in the A cells (20%) and somatostatin is synthesised and stored in the D cells (10%).
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This question is part of the following fields:
- Endocrinology
- Medicine
-
-
Question 92
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 93
Incorrect
-
During which stage does the mitotic apparatus dissolute?
Your Answer: Prometaphase
Correct 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 94
Incorrect
-
All of the following constitute small intestinal brush border enzymes except:
Your Answer: Isomaltase
Correct 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 95
Incorrect
-
Which afferent information is carried by the dorsal column?
Your Answer: Temperature
Correct Answer: Proprioception/ discriminative touch
Explanation:The posterior grey column (dorsal column) is responsible for carrying the sensation of proprioception, two-point discrimination, and vibration to the nucleus proprius, situated anterior to the substantia gelatinosa throughout the spinal cord.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 96
Incorrect
-
The transporter responsible for most glucose absorption in the lumen of the small intestine is called?
Your Answer: GLUT 2
Correct Answer: SGLT 1
Explanation:GLUT = Glucose transporter. GLUT are a family of proteins of different types. GLUT 1 is mainly expressed in erythrocytes, whereas GLUT 2 is mainly expressed by, liver cells and renal tubular cells. GLUT 5 is a sucrose transporter in enterocytes. SGLT- Sodium-dependent glucose cotransporter or sodium-glucose linked transporter are a family of proteins of different types. SGLT1 transporter is found in the intestinal mucosa of the small intestine and SGLT2 in the proximal tubule of the nephron.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
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Question 97
Incorrect
-
Which cell secretes parathyroid hormone?
Your Answer:
Correct Answer: Chief cells
Explanation:Parathyroid chief cells, also known as parathyroid principal cells or parathyroid cells, are the most prevalent type of cell in the parathyroid gland and the only ones present at birth. They secrete parathyroid hormone (PTH).
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This question is part of the following fields:
- Endocrinology
- Medicine
-
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Question 98
Incorrect
-
Which lipoprotein is responsible for lowering of plasma lipids?
Your Answer:
Correct Answer: HDL
Explanation:High-density lipoproteins (HDL) are one of the five major groups of lipoproteins. Lipoproteins are complex particles composed of multiple proteins which transport all fat molecules (lipids) around the body within the water outside cells. Unlike the larger lipoprotein particles which deliver fat molecules to cells, HDL particles remove fat molecules from cells.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 99
Incorrect
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Nucleic acids are split into nucleotides in the:
Your Answer:
Correct Answer: Intestine
Explanation:The pancreas is the major source for all the digestive enzymes including nucleases which split nucleic acids into nucleotides primarily in the small intestine.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 100
Incorrect
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A 62 year old female complains of pain and stiffness in her shoulders. She also finds it difficult to get out of her chair. From the list of symptoms below, choose the one most likely to support the diagnosis of polymyalgia rheumatica.
Your Answer:
Correct Answer: Low grade fever
Explanation:Polymyalgia rheumatica is an inflammatory disease which usually causes stiffness and pain in the shoulder – this can also occur in the pelvic girdle muscles. Its onset can either be subacute or acute and is associated with a systemic inflammatory response. This, therefore, causes symptoms such as fever, weight loss, anorexia, and malaise. Polymyalgia rheumatica is unpredictable in its course and it is known that 30 per cent of patients also present with giant cell arteritis. The cause of this disease is unknown but studies have shown it have infectious origins. Diagnosis of polymyalgia rheumatica can be difficult and other inflammatory diseases have to be excluded first. Patients with this disease are usually over 60 years of age (it is very rarely seen in those under 50). Muscle weakness does not present, although this can be hard to assess when the patient is in pain. Low-grade fever and weight loss are typical of this disease due to chronic inflammation. As such, weight gain is very rare and peripheral joints are usually not affected (they can be affected but it is very rare). Also, muscle tenderness is not a specific symptom of the disease – it is therefore not a classical finding of polymyalgia rheumatica. Although patients usually complain of stiffness and pain, the muscles are usually not significantly tender – this is usually more associated with fibromyalgia or myositis. When investigated, a normochromic/normocytic anaemia; a raised erythrocyte sedimentation rate often over 50 mm/hr., and raised C reactive protein are usually revealed. Symptoms of giant cell arteritis should also be sought, such as headaches, visual disturbances, TIAs (transient ischemic attacks), jaw claudication, and thickened temporal arteries. The patient response to a moderate dose of steroids is useful when confirming a diagnosis of polymyalgia rheumatica. The maximum dose of prednisolone should not exceed 20mg once a day. After treatment, patients should show a 70 per cent improvement in symptoms within a month (between 3-4 weeks). Inflammatory markers should also fall back to their normal levels. Non-steroidal anti-inflammatories are of little use and are associated with morbidity. There is also little evidence for the use of steroidal-sparing agents.
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This question is part of the following fields:
- Geriatrics
- Medicine
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