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Question 1
Correct
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The V wave in the jugular pulse is caused by:
Your Answer: Atrial filling
Explanation:The v wave reflects the passive increase in pressure and volume of the right atrium as it fills in late systole and early diastole.
The jugular vein pulsations usually have two elevations and two troughs. The first elevation (a wave) corresponds to the slight rise in atrial pressure resulting from atrial contraction. The first descent (x descent) reflects a fall in atrial pressure that starts with atrial relaxation. The second elevation (v wave) corresponds to ventricular systole when blood is entering the right atrium from the vena cavae while the tricuspid valve is closed. Finally, the second descent (y descent) reflects falling right atrial pressure as the tricuspid valve opens and blood drains from the atrium into the ventricle.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 2
Correct
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Coronary arteries fill up during
Your Answer: Diastole
Explanation:During contraction of the ventricular myocardium (systole), the subendocardial coronary vessels (the vessels that enter the myocardium) are compressed due to the high ventricular pressures. This compression results in momentary retrograde blood flow (i.e., blood flows backward toward the aorta) which further inhibits perfusion of myocardium during systole. However, the epicardial coronary vessels (the vessels that run along the outer surface of the heart) remain open. Because of this, blood flow in the sub endocardium stops during ventricular contraction. As a result, most myocardial perfusion occurs during heart relaxation (diastole) when the subendocardial coronary vessels are open and under lower pressure.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 3
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 4
Incorrect
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Calcium is transported over the brush border in the gut, via which transporter / channel?
Your Answer: Calcium / Na+ exchanger
Correct Answer: TRPV 6
Explanation:Transient Receptor Potential Vanilloid 6 or TRPV 6 is a calcium channel located in the cell membrane which is present in a variety of organs, including small intestine, oesophagus, stomach, colon, placenta, kidney, and uterus. In the intestine, it is located in the apical brush-border membrane of the enterocyte, regulating the entry of calcium into the cell.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 5
Correct
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In which area is depolarization initiated?
Your Answer: SA node
Explanation:SA node is the pacemaker of the heart. It determines the rate of contractions. It is the place where depolarization is initiated. It exhibits phase 4 depolarization or automaticity. Electrical impulses then spread to the AV node, purkinje fibers, bundle of his and the ventricular muscles.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 6
Incorrect
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An 81 year old male patient was admitted after an ischaemic stroke. Physical examination reveals left hemiparesis. How would you classify this hemiparesis based on the WHO International Classification of Functioning, Disability and Health?
Your Answer: Activity limitation
Correct Answer: Impairment of body function
Explanation:Symptoms and signs are classified as ‘impairment of body function’. The types of impairment classified as ‘activity limitation’ include difficulties that a patient may have in executing certain activities. The type of impairment classified as ‘participation restriction’ are problems a patient may have in social roles. The type of impairment classified as ‘pathology’ would be the diagnosis/disease. Right total anterior circulation infarct relates to the Oxford Bamford classification for stroke.
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This question is part of the following fields:
- Geriatrics
- Medicine
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Question 7
Correct
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Which of the following with regard to DNA mutations does not fit:
Your Answer: All gene mutations cause clinical disease entities
Explanation:All gene mutations do not cause a clinical manifestation of the disease, some gene mutations are silent mutations. They are present but do not cause any disease.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 8
Incorrect
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Digoxin causes:
Your Answer: Hyperkalaemia
Correct Answer: Increase in cytosolic calcium concentration
Explanation:Digoxin is a positive inotrope which inhibits NA/K ATPase, increases cardiac contractility and can cause hypokalaemia.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 9
Correct
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Following an action potential, cytosolic Ca2+ is increased. The binding of free Ca2+ to troponin C results in all of the following except:
Your Answer: Weakening of the troponin i interaction with actin
Explanation:At rest, troponin i is bound to actin and tropomyosin and covers the site where the myosin head interacts with actin. When Calcium enters into the muscle, it binds with troponin C and cause a structural change in troponin i which moves out of the myosin binding site and causes the cross bridges between the actin and myosin filaments to occur.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 10
Incorrect
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The apical enzyme responsible for the oxidation and reaction of iodide with thyroglobulin is:
Your Answer: Iodotyrosine deiodinase
Correct Answer: Thyroid peroxidise
Explanation:Thyroid peroxidase is an enzyme that is secreted into the thyroid colloid. It works by oxidizing iodide ions into iodine which are incorporated into thyroglobulin, in order to produce T3 and T4.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 11
Incorrect
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All valves are closed in which phase of the cardiac cycle?
Your Answer: None of the above
Correct Answer: Isovolumetric relaxation
Explanation:The cardiac cycle refers to a complete heartbeat from its generation to the beginning of the next beat, and so includes the diastole, the systole, and the intervening pause.The first stage, diastole, is when the semilunar valves (the pulmonary valve and the aortic valve) close, the atrioventricular (AV) valves (the mitral valve and the tricuspid valve) open, and the whole heart is relaxed. The second stage, atrial systole, is when the atrium contracts, and blood flows from atrium to the ventricle.The third stage, isovolumic contraction is when the ventricles begin to contract, the AV and semilunar valves close, and there is no change in volume. The fourth stage, ventricular ejection, is when the ventricles are contracting and emptying, and the semilunar valves are open. During the fifth stage, isovolumic relaxation time, pressure decreases, no blood enters the ventricles, the ventricles stop contracting and begin to relax, and the semilunar valves close due to the pressure of blood in the aorta.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 12
Incorrect
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With regards to P53, which statement is NOT true?
Your Answer: P53 activates many gene expression pathways
Correct 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 13
Correct
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Which of the following forms one of the characteristic and functional cells making up the anterior pituitary gland?
Your Answer: Corticotrope
Explanation:The anterior pituitary, also known as adenohypophysis or pars anterior contains the following types of cells: – acidophil cells: somatotroph cells, which produce growth hormone; and lactotrophs, which produce prolactin- basophil cells: corticotropes, which produce adrenocorticotropic hormone; thyrotropes, which produce thyroid stimulating hormone; and – gonadotrophs, which produce luteinizing hormone and follicle stimulating hormone.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 14
Incorrect
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What is the primary cause of ketoacidosis in Type 1 diabetes?
Your Answer: Glycolysis
Correct Answer: Lipolysis
Explanation:in type 1 diabetics the lack of insulin in the bloodstream prevents glucose absorption, thereby inhibiting the production of oxaloacetate (a crucial precursor to the β-oxidation of fatty acids) through reduced levels of pyruvate (a by-product of glycolysis), and can cause unchecked ketone body production (through fatty acid metabolism or lipolysis) potentially leading to dangerous glucose and ketone levels in the blood.
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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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What is the function of migrating motor complex
Your Answer: Mixing contents of the gut
Correct Answer: Clears the gut of luminal contents in preparation of the next meal
Explanation:Migrating motor complexes (MMC) are waves of electrical activity that sweep through the intestines in a regular cycle during fasting. These motor complexes trigger peristaltic waves, which facilitate transportation of indigestible substances such as bone, fiber, and foreign bodies from the stomach, through the small intestine, past the ileocecal sphincter, and into the colon. The MMC occurs every 90–120 minutes during the interdigestive phase (between meals), and is responsible for the rumbling experienced when hungry. It also serves to transport bacteria from the small intestine to the large intestine, and to inhibit the migration of colonic bacteria into the terminal ileum.
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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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A 41 year old woman who has a history of SLE presents with a dry cough, dyspnoea and fever. She is being treated with a monthly dose of IV cyclophosphamide for Grade IV nephropathy. The last cyclophosphamide dose was 10 years ago. Lab investigations are as follows: WCC: 2.3 (lymphocyte count 0.7)Platelets: 81Hb: 10.5ESR: 56CRP: 43PO2: 7.2 kPa, PCO2: 3.6 kPa after walking out to the toilet.Chest X ray was unremarkable apart from some patchy pulmonary infiltration.What is the likely diagnosis?
Your Answer: Pneumocystis carinii pneumonia (PCP)
Explanation:Pneumocystis carinii pneumonia, is an opportunistic fungal lung infection occurring almost exclusively in immunocompromised individuals. In 50% of cases, PCP is the first manifestation of AIDS (acquired immune deficiency syndrome), but it may be caused by other immunodeficiency disorders. PCP should be suspected in patients with a history of progressive dyspnoea and a dry cough with resistance to standard antibiotic treatment. Signs that support this diagnosis include a CD4 count < 200/μL, an increased beta-D-glucan level, and diffuse bilateral infiltrates on chest x-ray. Management of PCP includes high-dose trimethoprim/sulfamethoxazole (TMP/SMX), treatment of the underlying immunodeficiency disorder, and steroids in the case of severe respiratory insufficiency. TB is less likely to be present in this case as ESR is relatively low and chest x-ray appeared normal.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 17
Correct
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A 31 year old female complains of bilateral proximal muscle weakness. There is marked blanching of fingers especially in response to cold weather. Lab results are as follows: Anti Jo-1: positive ANA: positiveCK: 2000 U/LESR: 60mm/hrEMG: myopathic changesPresence of which of the following signifies the worst prognosis?
Your Answer: Interstitial lung disease
Explanation:Polymyositis is an inflammatory disorder causing symmetrical, proximal muscle weakness. It is thought to be a T-cell mediated cytotoxic process directed against muscle fibres. It may be idiopathic or associated with connective tissue disorders. It may also be associated with malignancy for example small cell lung carcinoma.Dermatomyositis is a variant of the disease where skin manifestations are prominent, for example a purple (heliotrope) rash on the cheeks and eyelids.It typically affects middle-aged, female: male 3:1. Features include proximal muscle weakness +/- tenderness, Raynaud’s phenomenon, respiratory muscle weakness, interstitial lung disease: e.g. fibrosing alveolitis or organising pneumonia, dysphagia, dysphonia. Investigations: elevated creatine kinase, other muscle enzymes (lactate dehydrogenase (LD), aldolase, AST and ALT) are also elevated in 85-95% of patients, EMG, muscle biopsy. Anti-Jo-1 antibodies are seen in pattern of disease associated with lung involvement, Raynaud’s and fever. Interstitial lung disease plays a major role in morbidity and mortality in patients with polymyositis and is considered a major risk factor for premature death in patients with myositis.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 18
Correct
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A 50-year-old hypertensive male on phenytoin and clobazam for partial seizures is also taking lisinopril, cimetidine, sucralfate, and allopurinol. The last few drugs were added recently. He now presents with ataxia, slurred speech, and blurred vision.Which recently added drug is most likely to be the cause of his latest symptoms?
Your Answer: Cimetidine
Explanation:The symptoms of ataxia, slurred speech and blurred vision are all suggestive of phenytoin toxicity. Cimetidine increases the efficacy of phenytoin by reducing its hepatic metabolism.Phenytoin has a narrow therapeutic index (10-20 mg/L) and its levels are monitored by measuring the total phenytoin concentration.Cimetidine is an H2 receptor antagonist used in the treatment of peptic ulcers. It acts by decreasing gastric acid secretion.Cimetidine also has an inhibitory effect on several isoforms of the cytochrome enzyme system including the CYP450 enzymatic pathway. Phenytoin is metabolized by the same cytochrome P450 enzyme system in the liver. Thus, the simultaneous administration of both these medications leads to an inhibition of phenytoin metabolism and thus increases its circulating levels leading to phenytoin toxicity.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 19
Correct
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Where does one find the thyroid receptors?
Your Answer: Cell nucleus
Explanation:Unlike many of the steroid receptors, inactive receptors for T3 are located in the nucleus. T4 is first converted into T3 within the cytoplasm of the cell, T3 then enters the nucleus and binds to its receptor. The hormone-receptor complex can now bind to DNA and activate specific genes.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 20
Incorrect
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A 45 year old male presents with lower backache and pain in his hips. Blood tests are normal except for elevated serum alkaline phosphatase which is 1200 IU/l (45-105). Radiological examination shows combined osteolytic and osteosclerotic lesions. What is the most common site of occurrence of this disease?
Your Answer: Tibia
Correct Answer: Pelvis
Explanation:The patient most likely suffers from Paget’s disease of the bone as his radiological examination shows both osteolytic and osteosclerotic lesions. Any bone or bones can be affected, but Paget’s disease occurs most frequently in the pelvis > lumbar spine > femur > thoracic spine > sacrum > skull > tibia.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 21
Correct
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Which of the following best describes the cardiac muscle?
Your Answer: Striated and involuntary
Explanation:Cardiac muscle (heart muscle) is an involuntary, striated muscle that is found in the walls and histological foundation of the heart, specifically the myocardium. Cardiac muscle is one of three major types of muscle, the others being skeletal and smooth muscle.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 22
Correct
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Which substance has the lowest taste threshold concentration, in other words which substance can be present in the lowest concentration before taste buds will respond?
Your Answer: Strychnine hydrochloride (bitter)
Explanation:The lowest concentration of a gustatory stimulus to which the taste buds respond is considered to be the threshold concentration for that substance. The threshold concentration for strychnine is 0.0001 mm; this is because it allows the body to detect potentially dangerous substances (bitter plant components) at lower concentrations.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 23
Correct
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A 30-year-old agitated male was brought to the emergency department by his friend. Though there is little previous history, the friend believes that he has been suffering from depression for several years, and his medications have been changed by his general practitioner quite recently.On examination the patient is agitated and confused, his pupils are dilated. He also has tremors, excessive sweating, and grinding of teeth. His heart rate is 118 beats/min, which is regular, and is febrile with a temperature of 38.5°C.What is the most probable diagnosis?
Your Answer: Serotonin syndrome
Explanation:The most probable diagnosis in this patient is serotonin syndrome.The serotonin syndrome is a cluster of symptoms and signs (range from barely perceptible tremor to life-threatening hyperthermia and shock). It may occur when SSRIs such as citalopram, escitalopram, fluoxetine, fluoxetine, paroxetine, and sertraline that impair the reuptake of serotonin from the synaptic cleft into the presynaptic neuron are taken in combination with monoamine oxidase inhibitors or tricyclic antidepressants. It has also been reported following an overdose of selective serotonin reuptake inhibitors (SSRIs) alone.Treatment:Most cases of serotonin syndrome are mild and will resolve with removal of the offending drug alone. After stopping all serotonergic drugs, management is largely supportive and aimed at preventing complications. Patients frequently require sedation, which is best facilitated with benzodiazepines.Antipsychotics should be avoided because of their anticholinergic properties, which may inhibit sweating and heat dissipation.
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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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A 70-year-old woman is having trouble in speaking following a stroke. Her limbs are paralyzed, both left upper and lower limbs. Which anatomical site is most likely affected?
Your Answer: Internal capsule
Explanation:– The given scenario is typical of lesion in internal capsule. – Memory impairment is caused by a hippocampal lesion, – Impairment of arousal, facial paresis, visual field defect, facial paresis, hemiataxia, and hemispacial neglect are just some of the conditions caused by thalamic lesion. – Brainstem stroke on the other hand causes breathing abnormality, altered consciousness, and blood pressure disorder.
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This question is part of the following fields:
- Geriatrics
- Medicine
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Question 25
Correct
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Question 26
Correct
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A 78-year-old male with long-standing Alzheimer's disease is being reviewed in your clinic. Which among the following is true regarding memantine, a drug which has been approved for the management of dementia?
Your Answer: It is an NMDA-receptor antagonist
Explanation:Memantine is an antagonist of the NMDA (N-Methyl-D-Aspartate)-receptor subtype of glutamate receptor. It is used to slow the neurotoxicity thought to be involved in Alzheimer’s disease and other neurodegenerative diseases.
Drug interactions:
- When given concomitantly with other NMDA-receptor antagonists (e.g., ketamine, amantadine) there is increased risk of psychosis.
- Dopamine agonists, L-dopa, and anticholinergics enhance effects of memantine.
- Antispasmodics (e.g., baclofen) enhance effects, as memantine has some antispasmodic effects.
- Drugs excreted by cationic transporters in the kidney (e.g. quinine, cimetidine, ranitidine) reduce excretion.
- Common adverse effects include dizziness, headache, confusion, diarrhoea, and constipation.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 27
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 28
Incorrect
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Question 29
Correct
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The chromosomes that principally encode for proteins or RNA molecules involved in mitochondrial function are found:
Your Answer: In the nucleus of each diploid cell
Explanation:While mitochondria have their own small circular DNA (mtDNA) that encodes some of the proteins and RNAs required for mitochondrial function, the majority of proteins involved in mitochondrial function are encoded by nuclear DNA. These nuclear genes are transcribed in the nucleus and then translated into proteins in the cytoplasm. The proteins are subsequently imported into the mitochondria.
Therefore, the correct answer is:
- In the nucleus of each diploid cell
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This question is part of the following fields:
- Genetics
- Medicine
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Question 30
Correct
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A 56 year old woman presents to the clinic complaining of shoulder pain that she has been experiencing for the last 4 weeks. She does not remember getting injured previously. The pain worsens on movement especially when she is moving the arm quickly. At night, lying on the affected side is painful. Examination reveals no erythema or swelling. However, pain is felt on passive abduction between 60 to 120 degrees and she is unable to abduct the arm past 70-80 degrees. Flexion and extension are intact. What is the most likely diagnosis?
Your Answer: Supraspinatus tendonitis
Explanation:Supraspinatus tendinopathy is a common and disabling condition that becomes more prevalent after middle age and is a common cause of pain in the shoulder. A predisposing factor is resistive overuse. This patient has the classic painful arc that is a sign of shoulder impingement characteristic of supraspinatus tendonitis.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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SESSION STATS - PERFORMANCE PER SPECIALTY
