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Question 1
Correct
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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: 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 2
Correct
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ADH causes?
Your Answer: Increased permeability of the collecting ducts to water
Explanation:Vasopressin (ADH) has three main effects:1. Increasing the water permeability of distal convoluted tubule and collecting duct cells in the kidney, thus allowing water reabsorption and excretion of more concentrated urine.2. Increasing permeability of the inner medullary portion of the collecting duct to urea by regulating the cell surface expression of urea transporters.3. Acute increase of sodium absorption across the ascending loop of Henle.
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This question is part of the following fields:
- Medicine
- Renal
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Question 3
Incorrect
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Which of the following statements is the most characteristic of primary Raynaud's phenomena?
Your Answer: Anti-nuclear antibody is positive in 70% of cases
Correct Answer: Fingers are symmetrically involved during an attack
Explanation:A typical attack may last less than an hour but can also persist for longer. In primary Raynaud’s, attacks are more likely symmetric, episodic, and without evidence of peripheral vascular disease. Patients more commonly have a negative ANA and normal inflammatory markers. There should be no evidence of tissue gangrene, digital pitting, or tissue injury in primary Raynaud’s. In contrast, patients with secondary Raynaud’s will describe attacks that are more frequent, painful, often asymmetric and may lead to digital ulcerations.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 4
Correct
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In which stage of mitosis are the chromosomes most obvious or prominent?
Your Answer: Metaphase
Explanation:Prophase begins when the nucleus envelope disintegrates and the chromosomes start to condense. The chromosomes consist of two sister chromatids that are joined at a constriction known as centromere. When the cell reaches the metaphase the chromosomes are completely condensed and ready to align on the equatorial plate.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 5
Incorrect
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Regarding integrins, which option is false?
Your Answer: Principally bind to ECM components such as fibrinogen, elastase and laminin
Correct Answer: Play no role in cell signalling.
Explanation:Integrins are transmembrane receptors that facilitate cell-extracellular matrix (ECM) adhesion. Upon ligand binding, integrins activate signal transduction pathways that mediate cellular signals such as regulation of the cell cycle, organization of the intracellular cytoskeleton, and movement of new receptors to the cell membrane. Integrins are obligate heterodimers, meaning that they have two subunits: α (alpha) and β (beta). Integrins play an important role in cell signalling by modulating the cell signalling pathways of transmembrane protein kinases such as receptor tyrosine kinases (RTK).
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 6
Correct
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Which cells secrete insulin?
Your Answer: B cells of the pancreatic islets
Explanation:Insulin is synthesised and stored by the B cells of the pancreatic islets (70% of islet cells), glucagon is synthesised and stored in the A cells (20%) and somatostatin is synthesised and stored in the D cells (10%).
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 7
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 8
Correct
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Regarding bronchial innervation which of the following is correct:
Your Answer: Alpha 1 receptors increase bronchial constriction
Explanation:Stimulation of β2 receptors results in smooth muscle relaxation and bronchodilation. α1 receptors cause smooth muscle contraction in the bronchioles although minor to the β2 effects.
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This question is part of the following fields:
- Medicine
- Respiratory
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Question 9
Correct
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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: 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 10
Incorrect
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Where is the lower border of the liver usually found?
Your Answer: 10th rib midclavicular line on right
Correct Answer: 10th rib anterior axillary line on right
Explanation:Assessment of liver margins is important clinically to determine the size of the liver and is done via percussion during the physical examination. The liver typically extends from the fifth intercostal space or 6th rib to the right costal margin in the midclavicular line and the 10th rib on anterior axillary line.
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This question is part of the following fields:
- Hepatobiliary
- Medicine
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Question 11
Correct
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The immunoglobulin found in the highest concentration in humans is
Your Answer: IgG
Explanation:Representing approximately 75% of serum antibodies in humans, IgG is the most common type of antibody found in the circulation. IgG molecules are created and released by plasma B cells.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 12
Correct
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Myocardial contractility is improved by:
Your Answer: Caffeine
Explanation:Caffeine and other theophyllines breakdown cAMP and have a positive ionotropic effect on the heart. Drugs like quinidine, procainamide and conditions like hypoxia and hypercapnia decreases the contractility of the heart.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 13
Incorrect
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A 75 year old man was brought to the clinic by his wife because lately he has lost interest in activities he previously enjoyed. His wife is worried and claims he's generally withdrawn. What would exclude depression in favour of dementia?
Your Answer: Poor short term memory
Correct Answer: Urinary incontinence
Explanation:Urinary incontinence is not a usual symptom of depression. A depressed patient is usually capable of maintaining control of his body sphincters. In dementia, however, urinary incontinence is an important and late symptom of the disease, non-related to any urinary tract pathology. It is rather related to the cognitive impairment caused by dementia.
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This question is part of the following fields:
- Geriatrics
- Medicine
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Question 14
Correct
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Question 15
Correct
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An important hormone controlling the differentiation of monocytes to osteoclasts, by inhibiting the RANKL/ RANK interaction is called?
Your Answer: Osteoprotegerin
Explanation:Osteoprotegerin, also known as osteoclastogenesis inhibitory factor (OCIF) is a glycoprotein that acts as a cytokine receptor. It works as a decoy receptor for the receptor activator of nuclear factor-kappaB ligand (RANKL)/osteoclast differentiation factor, thus inhibiting the differentiation of osteoclasts, which are capable of resorbing bone. Osteoprotegerin has been proposed as a therapeutic agent for osteoporosis.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 16
Correct
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Which one of these features is typical of dermatomyositis?
Your Answer: Gottron's papules over knuckles of fingers
Explanation:Dermatomyositis is a long-term inflammatory disorder which affects muscles. Its symptoms are generally a skin rash and worsening muscle weakness in the proximal muscles (for example, the shoulders and thighs) over time. These may occur suddenly or develop over months. Other symptoms may include weight loss, fever, lung inflammation, or light sensitivity. Complications may include calcium deposits in muscles or skin.The skin rash may manifest as aheliotrope (a purplish color) or lilac, but may also be red. It can occur around the eyes along with swelling, as well as the upper chest or back ( shawl sign) or V-sign above the breasts and may also occur on the face, upper arms, thighs, or hands. Another form the rash takes is called Gottron’s sign which are red or violet, sometimes scaly, slightly raised papules that erupt on any of the finger joints (the metacarpophalangeal joints or the interphalangeal joints)
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This question is part of the following fields:
- Dermatology
- Medicine
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Question 17
Correct
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Which of the following is a characteristic clinical finding of opioid poisoning?
Your Answer: Bradycardia
Explanation:Opioid poisoning is classically associated with pinpoint pupils, reduced respiratory rate, bradycardia, drowsiness and coma. Hypothermia is a feature of barbiturate poisoning, while sweating and lacrimation are seen in cases of opiate withdrawal.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 18
Correct
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5-methyltetrahydrofolate (Methyl THF) is converted to THF with the help of which of the following?
Your Answer: B 12
Explanation:MTR, also known as methionine synthase, is a methyltransferase enzyme, which uses the Vitamin B12 to transfer a methyl group from 5-methyltetrahydrofolate to homocysteine, thereby generating tetrahydrofolate (THF) and methionine. This functionality is lost in vitamin B12 deficiency, resulting in an increased homocysteine level and the trapping of folate as 5-methyl-tetrahydrofolate, from which THF (the active form of folate) cannot be recovered. THF plays an important role in DNA synthesis so reduced availability of THF results in ineffective production of cells with rapid turnover, in particular red blood cells, and also intestinal wall cells which are responsible for absorption.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 19
Correct
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The ENaC Transporter occurs in which part of the renal tubule?
Your Answer: Collecting duct
Explanation:The epithelial sodium channel (ENaC) is a membrane-bound ion channel that is selectively permeable to Na+ ions. It is involved primarily in the reabsorption of sodium ions at the collecting ducts of the kidney’s nephrons.
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This question is part of the following fields:
- Medicine
- Renal
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Question 20
Incorrect
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What causes increased insulin sensitivity?
Your Answer: Growth hormone treatment
Correct Answer: Exercise
Explanation:Physical activity, through its effect on insulin sensitivity, is one of the main modifiable risk factors for type 2 diabetes. It is estimated that by each weekly 500 kcal increment in exercise related energy consumption, the lifetime risk of suffering from type 2 diabetes is reduced by 9%. Up to two hours after exercise, glucose uptake is elevated due to insulin independent mechanisms; however, insulin sensitivity remains increased for at least 16 hours after exercising.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 21
Correct
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A 50-year-old farmer, under treatment for depression, presents to the emergency department following an intentional overdose of an unidentified substance. On examination, he was found to be bradycardic, hypotensive, hyper-salivating, and disoriented. On ocular examination, his pupils were found to be miotic. What is the most likely substance he ingested?
Your Answer: An organophosphate insecticide
Explanation:The farmer has most likely ingested an organophosphate insecticide.Organophosphorus compounds are used widely as:• Insecticides – Malathion, parathion, diazinon, dichlorvos• Nerve gases – Soman, sarin, tabun, VX• Ophthalmic agents – Echothiophate• Antihelmintics – Trichlorfon• Herbicides – merphos• Industrial chemical (plasticizer) – Tricresyl phosphateSigns and symptoms of Organophosphorus Poisoning (OPP) can be classified as:• Muscarinic effects:o Cardiovascular – Bradycardia, hypotensiono Respiratory – Rhinorrhoea, bronchorrhea, bronchospasm, cough, severe respiratory distresso Gastrointestinal – Hypersalivation, nausea and vomiting, abdominal pain, diarrhoea, faecal incontinenceo Genitourinary – Incontinenceo Ocular – Blurred vision, miosiso Glands – Increased lacrimation, diaphoresis• Nicotinic effects:o Muscle fasciculation, weakness, cramping, diaphragmatic failure, and autonomic side effects include: hypertension, tachycardia, and mydriasis.• Central nervous system (CNS) effects:o Anxiety, emotional lability, restlessness, confusion, ataxia, tremors, seizures, coma, apnoeaMainstay Treatment:• Decontamination• Securing Airway, Breathing and Circulation• Atropine• Pralidoxime• Benzodiazepines
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 22
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 23
Incorrect
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What is the main reason for checking the urea and electrolytes prior to commencing a patient on amiodarone?
Your Answer: To detect a metabolic acidosis
Correct Answer: To detect hypokalaemia
Explanation:All antiarrhythmic drugs have the potential to cause arrhythmias. Coexistent hypokalaemia significantly increases this risk.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 24
Correct
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An 87-year-old woman had to double up her dosage of morphine 60mg into 120mg twice a day, in addition to another 10mg oral Morphine 6 times a day. What is the best method of management?
Your Answer: Subcutaneous morphine infusion
Explanation:Stable dose of Morphine is essential for chronic cases of pain that are non-malignant in origin. Using the SC route avoids having to intravenously cannulate a patient and allows for a continuous infusion of drugs over a calculated period of time providing constant dosing A significant advantage is that plasma levels of a drug are much more stable, and appropriate symptom control can be achieved without the toxic effects of the peaks and troughs resulting from episodic drug administration.
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This question is part of the following fields:
- Geriatrics
- Medicine
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Question 25
Incorrect
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The complete oxidation of 1 molecule of glucose to CO2 and H20 produces a total of __ATP.
Your Answer: 16
Correct Answer: 38
Explanation:Textbooks often state that 38 ATP molecules can be made per oxidised glucose molecule during cellular respiration (2 from glycolysis, 2 from the Krebs cycle, and about 34 from the electron transport system). However, this maximum yield is never quite reached because of losses due to leaky membranes as well as the cost of moving pyruvate and ADP into the mitochondrial matrix, and current estimates range around 29 to 30 ATP per glucose.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 26
Correct
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Which glucose transporter is responsible for the uptake of dietary glucose from the gut?
Your Answer: SGLT1
Explanation:SGLT 1 is responsible for the uptake of glucose via secondary active transport from the small intestine and the renal tubules.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 27
Incorrect
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Which of the following is true for P 53:
Your Answer: It binds e2f and stops the cell cycle at the g 1 phase
Correct Answer: It is induced by ‘broken’ DNA
Explanation:All of the above mentioned statements are true regarding tumour suppressor genes.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 28
Incorrect
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The axons of the POST ganglionic neurons are mostly?
Your Answer: Α fibers
Correct Answer: C fibers
Explanation:According to Erlanger- Grasser classification preganglionic fibers are B fibers whereas post ganglionic fibers are C fibers.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 29
Correct
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A 38-year-old woman has a melanocytic naevi on her left forearm.Which of the following features do not suggest malignant change?
Your Answer: Decrease in size
Explanation:Melanocytic nevi are benign neoplasms or hamartomas composed of melanocytes. Melanocytes are derived from the neural crest and migrate during embryogenesis to selected ectodermal sites (primarily the skin and the CNS), but also to the eyes and the ears.They tend to appear during early childhood and during the first 30 years of life. They may change slowly, becoming raised, changing color or gradually fading.. Pregnancy can increase the number of naevi as well as the degree of hyperpigmentation.They may become malignant and this should be suspected if the naevus increases in size, develops an irregular surface or becomes darker, itches or bleeds.
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This question is part of the following fields:
- Dermatology
- Medicine
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Question 30
Incorrect
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Which one of the following statements regarding the normal distribution is correct?
Your Answer: 99.7% of values lie within 2 standard deviations of the mean
Correct Answer: Mean = mode = median
Explanation:Normal distribution, also known as the Gaussian distribution, is a probability distribution that is symmetric about the mean. The normal distribution has the following properties:- It is symmetric around the mode, the median and the mean of the distribution.- It is unimodal- The area under the curve and over the x-axis is unity (i.e. equal to one).- Its density has two inflection points.- Its density is log-concave.The standard deviation (SD) is a measure of how much dispersion exists from the mean. SD = square root (variance)
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This question is part of the following fields:
- Medicine
- Research Skills
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Question 31
Correct
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Regarding the innervation of cerebral blood vessels, which of the following triggers a vasoconstrictor effect?
Your Answer: Neuropeptide-Y
Explanation:Substance P is a potent vasodilator, VIP or vasoactive intestinal peptide has vasodilator properties in the intestines. PHM 27 is a potent calcitonin receptor agonist; endogenous analogue of human VIP. CGRP or Calcitonin Gene-Related Peptide is a vasodilator which is found to play an important role in migraines. Neuropeptide Y is a strong vasoconstrictor.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 32
Correct
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Vagotomy leads to the following:
Your Answer: Irregular and chaotic peristalsis
Explanation:The Vagus nerve is primarily responsible for autonomic regulation involved in heart, lung and gastrointestinal function. The gastric branches supply the stomach. The right branch joins the celiac plexus and supplies the intestines. Vagotomy involves cutting of the vagus nerve or its branches which is a now-obsolete therapy that was performed for peptic ulcer disease. Vagotomy causes a decrease in peristalsis and a change in the emptying patterns of the stomach.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 33
Correct
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In a normal heart rate at rest, the left ventricular end-diastolic volume is ….
Your Answer: 100-130 ml
Explanation:In cardiovascular physiology, end-diastolic volume (EDV) is the volume of blood in the right and/or left ventricle at end load or filling in (diastole) or the amount of blood in the ventricles just before systole. Because greater EDVs cause greater distention of the ventricle, EDV is often used synonymously with preload, which refers to the length of the sarcomeres in cardiac muscle prior to contraction (systole). End-diastolic volume: Right = 144 mL(± 23mL) & Left = 142 mL (± 21 mL).
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 34
Incorrect
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Using the Cockcroft-Gault formula, what will the estimated creatinine clearance be of a 55 year old male who weighs 75kg and has a serum creatinine of 150mg/dL?
Your Answer: 0.26ml/min
Correct Answer: 0.59ml/min
Explanation:A commonly used surrogate marker for estimate of creatinine clearance is the Cockcroft-Gault (CG) formula, which in turn estimates GFR in ml/min:CCr = [(140-age) x Mass(kg)]/[72 x serum creatinine (mg/dL)](multiply by 0.85 for women)Therefore CCr = (85 x 75)/(72 x 150) = 0.59
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This question is part of the following fields:
- Medicine
- Renal
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Question 35
Correct
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Which statement is correct about the clinical state of methemoglobinemia?
Your Answer: May arise due to a hereditary deficiency of NADH.
Explanation:Methaemoglobin is a form of haemoglobin that contains ferric [Fe3+] iron and has a decreased ability to bind oxygen. Spontaneously formed methaemoglobin is normally reduced by protective enzyme systems, e.g., NADH methaemoglobin reductase, hence a deficiency of NADH may result in increased levels of methaemoglobin
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This question is part of the following fields:
- Haematology
- Medicine
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Question 36
Correct
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With regards to the Na+/K+ ATPase, which one of the following is correct?
Your Answer: 3 Na+ released into the extracellular fluid
Explanation:Na+/K+ pump or sodium–potassium pump is an enzyme found in the plasma membrane. This pumping is active (i.e. it uses energy from ATP) and is important for cell physiology. Its simple function is to pump 3 sodium ions out for every 2 potassium ions taken in and since they both have equal ionic charges, this creates a electrochemical gradient between a cell and its exterior.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 37
Incorrect
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Which of the following is not a feature of Liddle’s syndrome?
Your Answer: Hypertension
Correct Answer: Autosomal recessive inheritance
Explanation:Liddle’s syndrome is a rare autosomal dominant condition characterized by early, and frequently severe, high blood pressure associated with low plasma renin activity, metabolic alkalosis, low blood potassium, and normal to low levels of aldosterone. Liddle syndrome involves abnormal kidney function, with excess reabsorption of sodium and loss of potassium from the renal tubule, and is treated with a combination of low sodium diet and potassium-sparing diuretic drugs (e.g., amiloride).
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 38
Correct
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A 22-year-old university student is admitted after taking drugs at a night club. Which of the following features suggest she had taken ecstasy (MDMA)?
Your Answer: A pyrexia of 40°C
Explanation:MDMA commonly known as ecstasy or molly, is a psychoactive drug primarily used as a recreational drug. The desired effects include altered sensations, increased energy, empathy, and pleasure. Features of MDMA abuse include hyponatraemia, tachycardia, hyperventilation, and hyperthermia.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 39
Correct
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The Wiebel-Palade body found in the endothelial cells is responsible for the production and release of which factor?
Your Answer: Von Willebrand factor
Explanation:Weibel-Palade bodies are the storage granules of endothelial cells, the cells that form the inner lining of the blood vessels and heart. They store and release two principal molecules, von Willebrand factor and P-selectin, and thus play a dual role in haemostasis and inflammation.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 40
Incorrect
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In the life cycle of plasmodium species:
Your Answer: Merozoites are only in the red cell cycle
Correct Answer: Merozoites are released from the liver and enter the red blood cell
Explanation:Plasmodium is a genus of parasitic protozoa, many of which cause malaria in their hosts. The parasite always has two hosts in its life cycle: a Dipteran insect host and a vertebrate host. Sexual reproduction always occurs in the insect, making it the definitive host.The life-cycles of Plasmodium species involve several different stages both in the insect and the vertebrate host. These stages include sporozoites, which are injected by the insect vector into the vertebrate host’s blood. Sporozoites infect the host liver, giving rise to merozoites and (in some species) hypnozoites. These move into the blood where they infect red blood cells. In the red blood cells, the parasites can either form more merozoites to infect more red blood cells, or produce gametocytes which are taken up by insects which feed on the vertebrate host. In the insect host, gametocytes merge to sexually reproduce. After sexual reproduction, parasites grow into new sporozoites, which move to the insect’s salivary glands, from which they can infect a vertebrate host bitten by the insect.
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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Question 41
Correct
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Where does most fat digestion begin?
Your Answer: Duodenum
Explanation:Digestion of some fats can begin in the mouth where lingual lipase breaks down some short chain lipids into diglycerides. However fats are mainly digested in the small intestine (in the duodenum). The presence of fat in the small intestine produces hormones that stimulate the release of pancreatic lipase from the pancreas and bile from the liver which helps in the emulsification of fats for absorption of fatty acids.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 42
Correct
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The production of bile is increased by: Stimulation of the ____ nerve and the hormone ____.
Your 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 43
Correct
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High titre of which of the following antibodies is not considered diagnostic for the mentioned disease?
Your Answer: Rheumatoid factor in rheumatoid arthritis (RA)
Explanation:Diagnosis of RA is mainly based on clinical features (e.g., morning stiffness, symmetrical joint swelling) and laboratory tests (e.g., anti-CCP). Rheumatoid factor is not very specific for this disease and hence has low reliability. X-ray findings (e.g., soft tissue swelling or joint space narrowing) occur late in the disease and are therefore not typically used for diagnosis.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 44
Correct
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The largest energy reserves among both lean and obese subjects are from?
Your Answer: Fatty acids
Explanation:The energy required for sustained exercise is provided by the oxidation of two fuels, glucose stored as glycogen in the liver and muscle, and long-chain fatty acids, stored as adipose tissue triglycerides. The latter provides the largest energy reserve in the body.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 45
Correct
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Which of these vitamins is not found in plants?
Your Answer: Vitamin B12
Explanation:No fungi, plants, nor animals (including humans) are capable of producing vitamin B12. Only bacteria and archaea have the enzymes needed for its synthesis. Proved food sources of B12 are animal products (meat, fish, dairy products).
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This question is part of the following fields:
- Haematology
- Medicine
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Question 46
Correct
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Embryologically the anterior pituitary is formed from?
Your Answer: Rathkes pouch
Explanation:The ectoderm, located in the roof of the pharynx, forms Rathke’s pouch, which comes into contact with the ectoderm of the developing brain. The pouch eventually separates from the pharynx, becoming the anterior pituitary.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 47
Correct
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Which of the following is not true regarding mitochondrial chromosome disorders?
Your Answer: Because mitochondrial chromosomes have no introns in their genes, any point mutation has a low likelihood of having an effect.
Explanation:Any point mutation in any part of the mitochondrial DNA will lead to a mutated mitochondria and will likewise have its ill effect on the body.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 48
Correct
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Regarding gustatory sensation:
Your Answer: The sensory taste buds on the anterior two-thirds of the tongue travel to the chorda tympani branch of the facial nerve
Explanation:There are three morphologically distinct types of taste buds including; circumvallate, fungiform and foliate. Circumvallate are rounded structures arranged in a v on the back of the tongue. The posterior third travels to glossopharyngeal nerve.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 49
Correct
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The following are Gram positive rods:
Your Answer: Clostridia
Explanation:Examples of Gram positive bacilli:Bacillus genusClostridium genusCorynebacterium genusListeria genusPropionibacterium genusExamples of Gram negative bacilli:Bacteroides genusCitrobacter genusEnterobacter genusEscherichia genusPseudomonas genusProteus genusSalmonella genusSerratia genusShigella genusYersinia genus
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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Question 50
Correct
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Question 51
Correct
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Which part of the chromosome plays a role in preserving its integrity and stability?
Your Answer: Telomere
Explanation:Telomeres are non coding DNA plus proteins that are found at the end of the linear chromosomes. They maintain the integrity of the chromosomes and prevent their shortening
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This question is part of the following fields:
- Genetics
- Medicine
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Question 52
Correct
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Which of the following cells release histamines when they are activated by binding of specific antigens to cell fixed IgE molecules?
Your Answer: Basophils
Explanation:Mast cells and basophils both contain granules of vasoactive histamine in their cytosol. Both of them express IgE receptors on their cell surface and upon binding with a specific antigen they release their cytokines including histamine.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 53
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 54
Correct
-
Which of the following is false with regard to the following statement: Proto- oncogenes can be transformed to oncogenes in the following ways.
Your Answer: Inhibition of P53
Explanation:Proto oncogenes cannot be transformed into oncogenes due to inhibition of P53 gene. There has to be a mutation in the proto oncogene. All the other options are true.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 55
Correct
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Question 56
Correct
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Question 57
Correct
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A 34 year old woman presents to the emergency department due to right sided weakness. Past history reveals a DVT following the birth of her daughter, and two miscarriages. Head CT confirms an ischaemic stroke in the territory of left middle cerebral artery. What would be the most likely finding on echocardiography?
Your Answer: Normal
Explanation:The patient most likely suffers from antiphospholipid syndrome. The clinical criteria consist of vascular thrombosis and pregnancy morbidity. Vascular thrombosis is defined as one or more clinical episodes of arterial, venous, or small-vessel thrombosis in any tissue or organ confirmed by findings from imaging studies, Doppler studies, or histopathology. ASD, VSDs would cause paradoxical emboli and stroke, however the recurrent pregnancy loss in this case is strongly suggestive of antiphospholipid syndrome. The ECG would be normal in most cases associated with anti phospholipid syndrome.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 58
Correct
-
Male to male transmission is a key factor of which type of inheritance?
Your 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 59
Correct
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A 56 year old woman taking procainamide develops drug induced erythematosus. Which of the following features is the most characteristic of this condition?
Your Answer: It may occur with chlorpromazine
Explanation:Drug induced lupus is usually positive for antinuclear and antihistone antibodies, typically without renal or neurologic involvement. However, pulmonary involvement is common. Drugs that can induce lupus include isoniazid, hydralazine, procainamide, chlorpromazine, and other anticonvulsants.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 60
Correct
-
Chief cells secrete:
Your Answer: Pepsinogen and gastric lipase
Explanation:A gastric chief cell (or peptic cell, or gastric zymogenic cell) is a type of cell in the stomach that releases pepsinogen and gastric lipase.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 61
Correct
-
Which of the following statements is true regarding pulsus alternans?
Your Answer: It is found in association with a third heart sound
Explanation:Pulsus alternans is a physical finding with arterial pulse waveform showing alternating strong and weak beats. It is almost always indicative of left ventricular systolic impairment, and carries a poor prognosis. A pathological third heart sound is usually associated.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 62
Correct
-
The cerebellum consists of which three cell layers?
Your Answer: Granular, purkinje, molecular
Explanation:The cerebellar cortex consist of 3 layers; the molecular layer, the granular cell layer and the Purkinje cell layer in the middle.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 63
Correct
-
The coronary arteries fill during?
Your Answer: Diastole
Explanation:During systole the coronary arteries collapse as a result of the pressure due to contraction that is exerted on them. During diastole the heart muscle relaxes and the pressure on the coronary vessels is relieved allowing blood to flow through them to the subendocardium.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 64
Correct
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Question 65
Correct
-
The Cellular Theory of Ageing involves?
Your Answer: Loss of telomeres
Explanation:Cellular theories of aging propose that human aging is the result of cellular aging, whereby an increasing proportion of cells reach senescence, a terminal stage at which cells will cease to divide. This will limit the body’s ability to regenerate and to respond to injury or stress. Telomeres are bits of DNA on the ends of chromosomes that protect chromosomes from sticking to each other or tangling, which could cause DNA to abnormally function. As cells replicate, telomeres shorten at the end of chromosomes, and this process correlates to senescence or cellular aging.
Other theories include:
- The Free Radical Theory: Implicates the gradual accumulation of oxidative cellular damage as a fundamental driver of cellular aging. This theory has evolved over time to emphasize the role of free radical induced mitochondrial DNA (mtDNA) mutations and the accumulation of mtDNA deletions. Given the proximity of mtDNA to the electron transport chain, a primary producer of free radicals, it postulates that the mutations would promote mitochondrial dysfunction and concomitantly increase free radical production in a positive feedback loop. It is known that diet, lifestyle, drugs (e.g. tobacco and alcohol) and radiation etc., are all accelerators of free radical production within the body.
- Error theory: based on the idea that errors can occur in the transcription of the synthesis of DNA. These errors are perpetuated and eventually lead to systems that do not function at the optimum level. The organism’s aging and death are attributable to these events (Sonneborn, 1979).
- The Cross-Linking Theory: also referred to as the Glycosylation Theory of Aging. In this theory it is the binding of glucose (simple sugars) to protein, (a process that occurs under the presence of oxygen) that causes various problems. Once this binding has occurred the protein becomes impaired and is unable to perform as efficiently. Living a longer life is going to lead to the increased possibility of oxygen meeting glucose and protein and known cross-linking disorders include senile cataract and the appearance of tough, leathery and yellow skin.
- The Neuroendocrine Theory First proposed by Professor Vladimir Dilman and Ward Dean MD, this theory elaborates on wear and tear by focusing on the neuroendocrine system. This system is a complicated network of biochemicals that govern the release of hormones which are altered by the walnut sized gland called the hypothalamus located in the brain. The hypothalamus controls various chain-reactions to instruct other organs and glands to release their hormones etc. The hypothalamus also responds to the body hormone levels as a guide to the overall hormonal activity. But as we grow older the hypothalamus loses it precision regulatory ability and the receptors which uptake individual hormones become less sensitive to them. Accordingly, as we age the secretion of many hormones declines and their effectiveness (compared unit to unit) is also reduced due to the receptors down-grading
- The Membrane Theory of Aging: According to this theory it is the age-related changes of the cell’s ability to transfer chemicals, heat and electrical processes that impair it. As we grow older the cell membrane becomes less lipid (less watery and more solid). This impedes its efficiency to conduct normal function and in particular there is a toxic accumulation
- The Decline Theory: The mitochondria are the power producing organelles found in every cell of every organ. Their primary job is to create Adenosine Triphosphate (ATP) and they do so in the various energy cycles that involve nutrients such as Acetyl-L-Carnitine, CoQ10 (Idebenone), NADH and some B vitamins etc. Enhancement and protection of the mitochondria is an essential part of preventing and slowing aging. Enhancement can be achieved with the above mention nutrients, as well as ATP supplements themselves.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 66
Correct
-
A deficiency in Cyanocobalamin leads to which clinical deficiency syndrome?
Your Answer: Pernicious anaemia
Explanation:The main syndrome of vitamin B12 deficiency is pernicious anaemia. It is characterized by a triad of symptoms:Megaloblastic anaemiaGastrointestinal symptoms &Neurological symptoms
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 67
Correct
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Which part of the cerebellum is primarily responsible for interacting with the motor cortex and planning and programming movements?
Your 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 68
Correct
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What percentage of blood to the liver is supplied by hepatic artery?
Your Answer: 25%
Explanation:The liver receives a dual blood supply from the hepatic portal vein and hepatic arteries. The hepatic portal vein delivers approximately 75% of the liver’s blood supply, and carries venous blood drained from the spleen, gastrointestinal tract, and its associated organs. The hepatic arteries supply arterial blood to the liver, accounting for the remaining quarter of its blood flow.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 69
Correct
-
Which of the following conditions is associated with eosinophilia?
Your Answer: Ascaris
Explanation:Eosinophilia can be idiopathic (primary) or, more commonly, secondary to another disease. In the Western World, allergic or atopic diseases are the most common causes, especially those of the respiratory or integumentary systems. In the developing world, parasites are the most common cause e.g. Ascaris
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This question is part of the following fields:
- Haematology
- Medicine
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Question 70
Incorrect
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A 74-year-old man who has been diagnosed with atrial fibrillation and heart failure is being started on digoxin. What is the mechanism of action of digoxin?
Your Answer: Inhibits the Na+/K+ ATPase pump
Correct Answer:
Explanation:Digoxin works by inhibiting the Na+/K+ ATPase pump in cardiac myocytes. Here’s how it works:
- Inhibition of Na+/K+ ATPase: Digoxin binds to and inhibits the Na+/K+ ATPase pump, which is responsible for pumping sodium out of the cell and potassium into the cell.
- Increased intracellular sodium: Inhibition of this pump leads to an increase in intracellular sodium levels.
- Decreased activity of the sodium-calcium exchanger: The increased intracellular sodium reduces the activity of the sodium-calcium exchanger, which normally pumps calcium out of the cell in exchange for sodium.
- Increased intracellular calcium: As a result, intracellular calcium levels rise because less calcium is being extruded from the cell. The increased calcium is then stored in the sarcoplasmic reticulum.
- Enhanced contractility: During each action potential, more calcium is released from the sarcoplasmic reticulum into the cytoplasm, which enhances the contractility of the heart muscle (positive inotropic effect).
By increasing the force of contraction, digoxin helps improve cardiac output in patients with heart failure. Additionally, digoxin has vagomimetic effects, which can help control the heart rate in atrial fibrillation by increasing vagal tone and thereby reducing the conduction velocity through the atrioventricular node.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 71
Correct
-
Which of the following can trigger parietal cell secretion?
Your Answer: Gastrin
Explanation:The three agonists of parietal cell secretion are gastrin, acetylcholine and histamine. Parietal cells are responsible for the secretion of HCl and intrinsic factor.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 72
Incorrect
-
The predominant site in the lymph node where T lymphocytes are found is:
Your Answer: Cortex
Correct Answer: Paracortex
Explanation:Paracortex is found between the cortex and the medulla and it is composed of a non-nodular type of arrangement that is mostly made up of T cells.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 73
Incorrect
-
The length of DNA is generally measured in terms of the number of:
Your Answer: Nucleotides
Correct Answer: Base pairs
Explanation:As DNA is made up of nucleotides, its length is measured by the number of base pairs in the DNA molecules.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 74
Incorrect
-
A case-control study is being designed to look at the relationship between eczema and a new vaccine for yellow fever. What is the usual outcome measure in a case-control study?
Your Answer: Relative risk
Correct Answer: Odds ratio
Explanation:A case–control study (also known as case–referent study) is a type of observational study in which two existing groups differing in outcome are identified and compared on the basis of some supposed causal attribute. Case–control studies are often used to identify factors that may contribute to a medical condition by comparing subjects who have that condition/disease (the cases) with patients who do not have the condition/disease but are otherwise similar (the controls).An odds ratio (OR) is a statistic that quantifies the strength of the association between two events, A and B. The odds ratio is defined as the ratio of the odds of A in the presence of B and the odds of A in the absence of B or vice versa.
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This question is part of the following fields:
- Medicine
- Research Skills
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Question 75
Correct
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A 25-year-old female presents to the emergency department with severe breathlessness and tinnitus. She is under treatment for asthma and depression with albuterol and amitriptyline respectively.On examination, she seems agitated with a BP of 100/44, a pulse rate of 112 bpm, a respiratory rate of 30 cycles/min, and a temperature of 37.8'C.An arterial blood gas performed reveals:pH: 7.48 (7.36 – 7.44)pO2: 11.2 kPa (11.3 – 12.6 kPa)pCO2: 1.9 kPa (4.7 – 6.0 kPa)Bicarbonate: 13 mmol/l (20 – 28 mmol/L)What is the most probable diagnosis?
Your Answer: Salicylate poisoning
Explanation:The blood gas analysis provided above is suggestive of a mixed respiratory alkalosis and metabolic acidosis characteristic of salicylate overdose.Pathophysiology:The direct stimulation of the cerebral medulla causes hyperventilation and respiratory alkalosis.As it is metabolized, it causes an uncoupling of oxidative phosphorylation in the mitochondria. Lactate levels then increase due to the increase in anaerobic metabolism. This, along with a slight contribution from the salicylate metabolites result in metabolic acidosis.Tinnitus is characteristic and salicylate ototoxicity may produce deafness. Other neurological sequelae include encephalopathy and agitation, seizures and CNS depression and coma. Cardiovascular complications include tachycardia, hypotension, and dysrhythmias (VT, VF, and asystole).
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 76
Incorrect
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Question 77
Correct
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Question 78
Incorrect
-
Factors influencing cardiac output include which of the following?
Your Answer: Stroke volume
Correct Answer: All of the above
Explanation:There is a correlation between resting CO and body surface area. The output per min per square meter of body surface (the cardiac index) averages 3.2l.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 79
Incorrect
-
When 2 nucleotide chains of DNA bind together, thymine is bound to:
Your Answer: Amino acids
Correct Answer: Adenine
Explanation:As a general rule in the structure of DNA, thymine always binds to adenine with two hydrogen bonds, cytosine always binds to guanine with three hydrogen bonds and vice versa. However In the structure of RNA the only difference is that adenine binds to uracil instead of thymine. But thymine will always bind to adenine.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 80
Incorrect
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Select a factor which stimulates glucagon secretion.
Your Answer: Free fatty acids
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 81
Incorrect
-
With regards to the deiodinases, where would you find D1?
Your Answer: Brain
Correct Answer: Liver
Explanation:The liver produces an important amount of T3 by outer ring deiodination thanks to its elevated concentration of type I deiodinase. It can also be found in the kidney.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 82
Correct
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Question 83
Correct
-
Protozoa is part of which pathogenic group?
Your Answer: Eukaryotes
Explanation:Protozoa are a diverse group of unicellular eukaryotic organisms. Historically, protozoa were defined as single-celled organisms with animal-like behaviours, such as motility and predation.
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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Question 84
Correct
-
Which of the following statements is true of the beta- lactams:
Your Answer: Co-amoxiclav is more likely to cause obstructive jaundice than amoxicillin
Explanation:β-lactam antibiotics are a class of broad-spectrum antibiotics, consisting of all antibiotic agents that contain a β-lactam ring in their molecular structures. This includes penicillin derivatives (penams), cephalosporins (cephems), monobactams, and carbapenems. Most β-lactam antibiotics work by inhibiting cell wall biosynthesis in the bacterial organism and are the most widely used group of antibiotics. Bacteria often develop resistance to β-lactam antibiotics by synthesizing a β-lactamase, an enzyme that attacks the β-lactam ring. To overcome this resistance, β-lactam antibiotics are often given with β-lactamase inhibitors such as clavulanic acid. Immunologically mediated adverse reactions to any β-lactam antibiotic may occur in up to 10% of patients receiving that agent (a small fraction of which are truly IgE-mediated allergic reactions). Rarely, cholestatic jaundice has been associated with Co-amoxiclav (amoxicillin/clavulanic acid). The reaction may occur up to several weeks after treatment has stopped, and usually takes weeks to resolve. It is more frequent in men, older people, and those who have taken long courses of treatment; the estimated overall incidence is one in 100,000 exposures.
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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Question 85
Incorrect
-
A 23 year old male presents with a history of lower back pain for the last one year. Presence of which of the following features most likely points towards ankylosing spondylitis?
Your Answer: Presence of HLA-B27 antigen on tissue typing
Correct Answer: Bilateral erosion of sacroiliac joints on X-ray
Explanation:Bilateral erosions of the sacroiliac joints on pelvic radiographs of patients with ankylosing spondylitis are an important feature of the modified New York classification criteria. Although HLA-B27 is commonly associated with AS, it can also be found in normal individuals. Back stiffness is worse in the morning and gets better as the day progresses. Tenderness and limited lumbar motion can be associated with other spine problems as well and is not characteristic of rheumatoid arthritis.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 86
Incorrect
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A 35-year-old female has been recently diagnosed with hypertension. She's sexually active and is not using any birth control other than barrier method. Which among the following antihypertensives is contraindicated in this patient?
Your Answer: Hydralazine
Correct Answer: Lisinopril
Explanation:Among the following hypertensives, lisinopril (an ACE inhibitor) is contraindicated in patients who are planning for pregnancy.Per the NICE guidelines, when treating the woman in question, she should be treated as if she were pregnant given the absence of effective contraception. ACE inhibitors such as lisinopril are known teratogens and most be avoided.Drugs contraindicated in pregnancy:AntibioticsTetracyclinesAminoglycosidesSulphonamides and trimethoprimQuinolonesOther drugs:ACE inhibitors, angiotensin II receptor antagonistsStatinsWarfarinSulfonylureasRetinoids (including topical)Cytotoxic agentsThe majority of antiepileptics including valproate, carbamazepine, and phenytoin are known to be potentially harmful.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 87
Correct
-
The interstitium of the kidney is most hypertonic in the:
Your Answer: Papillary tip of the medulla
Explanation:The medullary interstitium is the tissue surrounding the loop of Henle in the renal medulla. It functions in renal water reabsorption by building up a high hypertonicity, which draws water out of the thin descending limb of the loop of Henle and the collecting duct system. This hypertonicity, in turn, is created by an efflux of urea from the inner medullary collecting duct.
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This question is part of the following fields:
- Medicine
- Renal
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Question 88
Incorrect
-
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: Brain stem
Correct 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 89
Correct
-
Which of the following types of reactions are a part of the phase II metabolism of a drug?
Your Answer: Conjugation
Explanation:Drug metabolism can be broadly classified into:Phase I (functionalization) reactions: also termed non-synthetic reactions, they include oxidation, reduction, hydrolysis, cyclization and de-cyclization. The most common and vital reactions are oxidation reactions. (Of the given enzymes only Alcohol dehydrogenase is involved in phase I drug metabolism. Succinate dehydrogenase, is a vital enzyme involved in the Kreb’s cycle and the mitochondrial electron transport chain). They are mainly catalysed by Cytochrome P-450 enzyme.Phase II (conjugation) reactions: occur following phase I reactions, they include reactions: glucuronidation and sulphate conjugation, etc. They are mostly catalysed by UDP-glucuronosyltransferase enzyme. Other phase II enzymes include: sulfotransferases, N-acetyltransferases, glutathione S-transferases and methyltransferases.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 90
Correct
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Question 91
Incorrect
-
The thalamic nuclei that project over wide regions of the neocortex are:
Your Answer: Midline and intralaminar nuclei
Correct Answer: Specific relay nuclei
Explanation:The thalamus is considered the relay station for sensory and motor stimuli. There are three basic types of thalamic nuclei: relay nuclei, association nuclei and non-specific nuclei. Relay nuclei receive very well defined inputs and project this signal to functionally distinct areas of the cerebral cortex. These include the nuclei that relay primary sensations and also the nuclei involved in feedback of cerebellar signals and basal gangliar output.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 92
Correct
-
Regarding blood supply to the heart;
Your Answer: Coronary arteries fill as the heart relaxes
Explanation:The heart muscles acts like the skeletal muscle in the fact that it also compress the vessels during contraction. As the pressure in the ventricle is slightly greater than in the aorta the coronary vessels collapse during systole. Blood flows through them during the diastole phase of contraction.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 93
Correct
-
Oxygen enters blood from the alveoli by:
Your Answer: Passive diffusion
Explanation:Oxygen enters blood from the alveoli by simple diffusion along a concentration gradient. Concentration of oxygen and the partial pressure of oxygen in the alveoli are higher than the partial pressure of oxygen in the blood. So, oxygen moves from alveoli into blood via simple diffusion according to the concentration gradient.
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This question is part of the following fields:
- Medicine
- Respiratory
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Question 94
Correct
-
Which one of the following diuretics is associated with metabolic acidosis?
Your Answer: Acetazolamide
Explanation:Acetazolamide is in the diuretic and carbonic anhydrase inhibitor families of medication. It works by decreasing the amount of hydrogen ions and bicarbonate in the body and can thus cause metabolic acidosis and electrolyte changes (hypokalaemia, hyponatremia).
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 95
Incorrect
-
What is the mechanism of action of sumatriptan?
Your Answer: 5-HT3 agonist
Correct Answer: 5-HT1 agonist
Explanation:Triptans are specific 5-HT1 agonists used in the acute treatment of migraine. They are generally used as first-line therapy in combination with an NSAID or paracetamol.
Sumatriptan acts as an agonist on 5-HT1B/1D receptors by inducing vasoconstriction in the basilar artery and blood vessels within the dura mater. The drug reduces peripheral nociception either by selective cranial vasoconstriction or by affecting trigeminovascular nerves.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 96
Correct
-
Complement system help dispose waste products after which natural process?
Your Answer: Apoptosis
Explanation:The complement system is a part of the immune system that enhances (complements) the ability of antibodies and phagocytic cells to clear microbes and damaged cells from an organism or apoptosis. It is part of the innate immune system.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 97
Correct
-
The AV Node:
Your 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 98
Correct
-
Iron absorption occurs primarily in which part of the GIT?
Your Answer: Duodenum
Explanation:Like most mineral nutrients, the majority of the iron absorbed from digested food or supplements is absorbed in the duodenum by enterocytes of the duodenal lining.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 99
Correct
-
In liver failure there is likely to be?
Your Answer: Bleeding disorders
Explanation:Liver failure can lead to several significant changes in the body’s physiology, but let’s review each option in the context of liver failure:
- Raised blood urea: This is not typical of liver failure. In liver failure, blood urea nitrogen (BUN) levels are often low because the liver is not effectively converting ammonia to urea.
- Increase in the albumin/globulin ratio in the blood: This is incorrect. In liver failure, albumin production decreases, leading to a lower albumin/globulin ratio.
- Bleeding disorders: This is possible, but it often fluctuates. Liver failure can lead to both bleeding tendencies due to decreased production of clotting factors and a hypercoagulable state due to the reduced synthesis of anticoagulant proteins like Protein C and S.
- Stable blood glucose level: This is incorrect. Liver failure often causes hypoglycemia because the liver’s ability to produce glucose via gluconeogenesis and glycogenolysis is impaired.
- Increased absorption of fat: This is incorrect. Liver failure can lead to decreased bile production, which is necessary for fat emulsification and absorption, resulting in decreased fat absorption.
Given these points, the most likely option related to liver failure would actually be issues related to bleeding complications.
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This question is part of the following fields:
- Hepatobiliary
- Medicine
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Question 100
Incorrect
-
In Jugular vein pressure the “a” wave represents?
Your Answer:
Correct Answer: Atrial systole
Explanation:The jugular venous pressure (JVP, sometimes referred to as jugular venous pulse) is the indirectly observed pressure over the venous system via visualization of the internal jugular vein. It can be useful in the differentiation of different forms of heart and lung disease. Classically three upward deflections and two downward deflections have been described: The upward deflections are the a (atrial contraction), c (ventricular contraction and resulting bulging of tricuspid into the right atrium during isovolumetric systole) and v = venous filling.The downward deflections of the wave are the x (the atrium relaxes and the tricuspid valve moves downward) and the y descent (filling of ventricle after tricuspid opening).
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 101
Incorrect
-
Endotoxin
Your Answer:
Correct Answer: Composed of Lipid A in liposaccharide in cell wall
Explanation:Lipopolysaccharides (LPS), also known as lipoglycans and endotoxins, are large molecules consisting of a lipid (lipid A) and a polysaccharide composed of O-antigen, outer core and inner core joined by a covalent bond; they are found in the outer membrane of Gram-negative bacteria, and elicit strong immune responses in animals.
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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Question 102
Incorrect
-
Troponin I is inhibited by calcium binding to:
Your Answer:
Correct Answer: Troponin c
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 103
Incorrect
-
Vasodilatation in skeletal muscle can be caused by:
Your Answer:
Correct Answer: Sympathetic cholinergic nerves
Explanation:In skeletal muscles some fibers that cause vasodilation run with the nerves of the sympathetic system but are cholinergic in nature. These nerves are not active during rest but become active during exercise and stress.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 104
Incorrect
-
A 26 year old woman is 32 weeks pregnant. She has a history of Sjogren Syndrome. The foetus would be at a risk for which of the following?
Your Answer:
Correct Answer: All correct
Explanation:Women with Sjögren syndrome are likely to experience more complications during pregnancy than women without an autoimmune disease as the anti-Ro and anti-La antibodies cross the placenta and lead to various life threatening complications. Studies show a high incidence of poor fetal outcomes for these patients. Congenital heart block, neonatal lupus, congestive cardiac failure, hydrops fetalis can all be caused as a result of Sjogren syndrome.
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This question is part of the following fields:
- Connective Tissue
- Medicine
-
-
Question 105
Incorrect
-
Which of the following provides the sympathetic nervous supply to the stomach?
Your Answer:
Correct Answer: Coeliac plexus
Explanation:Parasympathetic innervation to the stomach is from the vagus nerve and the sympathetic innervation is from the coeliac plexus.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
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Question 106
Incorrect
-
The pressure in the sinusoids is normally:
Your Answer:
Correct Answer: Lower than portal venous pressure
Explanation:The direction of transport of nutrients in the portal vein occurs from the portal vein to the hepatic sinusoids. Thus, he pressure of sinusoids should be lower than the pressure of he portal vein.
-
This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 107
Incorrect
-
Question 108
Incorrect
-
Which factor produced by the endothelium is responsible for the regulation of vascular cell growth?
Your Answer:
Correct Answer: Vascular endothelial growth factor (VEGF)
Explanation:VEGF is produced by the endothelial cells and is the major growth factor responsible for causing vasculogenesis. Some isoforms of this growth factor also have a prominent role in formation of lymphatic vessels.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 109
Incorrect
-
Which of the following is a physiological effect of pregnancy on the kidney?
Your Answer:
Correct Answer: Decreased creatinine
Explanation:A pregnant woman may experience an increase in kidney and ureter size. The glomerular filtration rate (GFR) commonly increases by 50%, returning to normal around 20 weeks postpartum. Plasma sodium does not change because this is offset by the increase in GFR. There is decreased blood urea nitrogen (BUN) and creatinine and potentially glucosuria (due to saturated tubular reabsorption).
-
This question is part of the following fields:
- Medicine
- Renal
-
-
Question 110
Incorrect
-
Activation of nitric oxide synthesis by endothelial cells is triggered by:
Your Answer:
Correct Answer: All of the above
Explanation:Acetylcholine, histamine, bradykinin, vasoactive intestinal peptide (VIP) and shear stress on the endothelial cells causing the release of NO. NO is formed from arginine and causes vasodilatation of the blood vessels.
-
This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 111
Incorrect
-
Question 112
Incorrect
-
Which neuron secretes glutamate as its neurotransmitter?
Your Answer:
Correct Answer: A delta and C pain fibers
Explanation:A delta and C fibers use glutamate as their primary neurotransmitter where it acts as a fast acting localized neurotransmitter.
-
This question is part of the following fields:
- Medicine
- Neurology
-
-
Question 113
Incorrect
-
Which of the following statements correctly describes a function of the parasympathetic innervation of the GI tract.
Your Answer:
Correct Answer: Parasympathetic cholinergic activity increases the activity of intestinal smooth muscle
Explanation:The parasympathetic nerves stimulate peristalsis and relax the sphincters; they also stimulate secretion. Acetylcholine is the neurotransmitter of the parasympathetic system.
-
This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 114
Incorrect
-
Which of the following drugs requires plasma level monitoring?
Your Answer:
Correct Answer: Vancomycin
Explanation:All patients require plasma-vancomycin measurement (after 3 or 4 doses if renal function normal, earlier if renal impairment). There is a risk of nephrotoxicity including renal failure, interstitial nephritis and ototoxicity.
-
This question is part of the following fields:
- Medicine
- Pharmacology
-
-
Question 115
Incorrect
-
The process whereby DNA fragments are separated by size and charge is called:
Your Answer:
Correct Answer: Gel electrophoresis
Explanation:Fragments of DNA of varying length can be separated on the basis of their charge and their size by a process called gel electrophoresis. Because DNA contains negatively charged phosphate groups, it will migrate in an electric field toward the positive electrode. Shorter chains migrate more rapidly through the pores of the gel, and thus separation depends on length. DNA bands in the gel can be visualized by various techniques including staining with dyes and autoradiography.
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This question is part of the following fields:
- Genetics
- Medicine
-
-
Question 116
Incorrect
-
In the body what are fatty acids broken down to?
Your Answer:
Correct Answer: Acetyl Co A
Explanation:Fatty acids are broken down into acetyl Co A. The acetyl-CoA produced by beta oxidation enters the citric acid cycle in the mitochondrion by combining with oxaloacetate to form citrate.
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This question is part of the following fields:
- Cell Biology
- Medicine
-
-
Question 117
Incorrect
-
A cohort study is being designed to look at the relationship between smoking and prostate cancer. What is the usual outcome measure in a cohort study?
Your Answer:
Correct Answer: Relative risk
Explanation:A cohort study is a particular form of longitudinal study that samples a cohort (a group of people who share a defining characteristic, typically those who experienced a common event in a selected period, such as birth or graduation), performing a cross-section at intervals through time. The relative risk (RR) or risk ratio is the ratio of the probability of an outcome in an exposed group to the probability of an outcome in an unexposed group. Relative risk is used in the statistical analysis of the data of experimental, cohort and cross-sectional studies, to estimate the strength of the association between treatments or risk factors, and outcomes.
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This question is part of the following fields:
- Medicine
- Research Skills
-
-
Question 118
Incorrect
-
A 28 year old man presents to the clinic with fatigue, exertional dyspnoea, abdominal discomfort, xerophthalmia and xerostomia. Examination reveals enlargement of the parotid glands bilaterally, hepatomegaly and peripheral motor neuropathy. Lab results are negative for RF, ANA, SS-A and SS-B antibodies. What is the most likely diagnosis?
Your Answer:
Correct Answer: Diffuse infiltrative lymphocytic syndrome (DILS)
Explanation:The Diffuse Infiltrative Lymphocytosis Syndrome (DILS) is a rare multisystemic syndrome described in HIV-infected patients. It is characterised by CD8(+) T-cell lymphocytosis associated with a CD8(+) T-cell infiltration of multiple organs. DILS is usually seen in uncontrolled or untreated HIV infection but can also manifest itself independently of CD4(+) T-cell counts. The syndrome may present as a Sjögren-like disease that generally associates sicca signs with bilateral parotiditis, lymphadenopathy, and extra glandular organ involvement. The latter may affect the lungs, nervous system, liver, kidneys, and digestive tract. Anomalies of the respiratory system are often identified as lymphocytic interstitial pneumonia. Facial nerve palsy, aseptic meningitis or polyneuropathy are among the more frequent neurological features. Hepatic lymphocytic infiltration, lymphocytic interstitial nephropathy and digestive tract lymphocytic infiltration account for more rarely noted complications. Sicca syndrome, organomegaly and/or organ dysfunction associated with polyclonal CD8(+) T-cell organ-infiltration are greatly suggestive of DILS in people living with HIV.
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This question is part of the following fields:
- Connective Tissue
- Medicine
-
-
Question 119
Incorrect
-
Which enzyme is responsible for the conversion of testosterone to dihydrotestosterone?
Your Answer:
Correct Answer: 5α-reductase
Explanation:The enzyme 5α-reductase synthesizes DHT from testosterone in the prostate, testes, hair follicles, and adrenal glands. This enzyme reduces the 4,5 double-bond of the testosterone. Relative to testosterone, DHT is much more potent as an agonist of the androgen receptor.
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This question is part of the following fields:
- Endocrinology
- Medicine
-
-
Question 120
Incorrect
-
Which of the following statements regarding influenza virus is correct?
Your Answer:
Correct Answer: Influenza is a RNA virus
Explanation:The Orthomyxoviruses are a family of RNA viruses that includes six genera: Influenza virus A, Influenza virus B, Influenza virus C, Isavirus, Thogotovirus and Quaranjavirus.The mechanism of the evolutionary force of antigenic shift allows influenza viruses to exchange genes with strains that infect different species. Under this mechanism, a human influenza virus could exchange genes with an avian strain, and that is how pandemic strains arise.
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This question is part of the following fields:
- Infectious Diseases
- Medicine
-
-
Question 121
Incorrect
-
Question 122
Incorrect
-
A 52 year old shopkeeper presents with pain in her hands. Examination reveals plaques on the extensor surfaces of her upper limbs and a telescoping deformity of both index fingers. Nails show pitting and horizontal ridging. The patient is most likely suffering from which of the following?
Your Answer:
Correct Answer: Arthritis mutilans
Explanation:Arthritis mutilans is a rare (occurs in only 5% of the patients) and extremely severe form psoriatic arthritis characterized by resorption of bones and the consequent collapse of soft tissue. When this affects the hands, it can cause a phenomenon sometimes referred to as ‘telescoping fingers.’ The associated nail changes are also characteristic of arthritis.
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This question is part of the following fields:
- Connective Tissue
- Medicine
-
-
Question 123
Incorrect
-
What is the primary problem of achalasia
Your Answer:
Correct Answer: Deficiency of myenteric plexus at the lower oesophageal sphincter
Explanation:Oesophageal achalasia is an oesophageal motility disorder involving the smooth muscle layer of the oesophagus is characterized by the failure of the lower oesophageal sphincter (LES) relaxation and aperistalsis, caused primarily by the loss of the inhibitory innervation of the oesophageal myenteric plexus.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 124
Incorrect
-
Glucose transport in the brain is mediated by:
Your Answer:
Correct Answer: GLUT 1
Explanation:The facilitative glucose transporter mediates the transport of glucose from blood into neurons and glia in the brain. The primary isoforms in the brain are GLUT1 detected at high concentrations.
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This question is part of the following fields:
- Medicine
- Neurology
-
-
Question 125
Incorrect
-
How are the long chain fatty acids (more than 10 to 12 carbon atoms) absorbed?
Your Answer:
Correct Answer: Re-esterified to triglycerides and enter the lymphatics as chylomicrons
Explanation:Short and medium chain fatty acids are absorbed into the blood via intestinal capillaries and travel through the portal vein. Long chain fatty acids are not directly released into the intestinal capillaries. They are re-esterified to triglycerides and are coated with cholesterol and protein, forming chylomicrons. Chylomicrons are released in the lymphatic system.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 126
Incorrect
-
In the basal ganglia, the Lentiform nucleus is formed by which two nuclei?
Your Answer:
Correct Answer: Putamen and Globus pallidus
Explanation:The Basal Ganglia are composed of the following structures: Caudate, putamen, Globus pallidus, subthalamic nucleus and substantia nigra.
The Lentiform nucleus is a biconvex structure located within the basal ganglia of the brain. It is composed of two nuclei:
- Putamen: This is the outer part of the Lentiform nucleus and is involved in regulating movements and various types of learning.
- Globus pallidus: This is the inner part of the Lentiform nucleus and is divided into two segments: the external segment (GPe) and the internal segment (GPi). It plays a key role in the regulation of voluntary movement.
These two structures together form the Lentiform nucleus, which is an integral part of the basal ganglia system involved in motor control.
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This question is part of the following fields:
- Medicine
- Neurology
-
-
Question 127
Incorrect
-
The hyperpolarization phase of pacemaker cells is dominated by ____ current.
Your Answer:
Correct Answer: K+
Explanation:The hyperpolarization phase is a continuation of the repolarization phase but the membrane potential dips below the resting membrane potential. This results due to the fact that the K+ channels take a longer time to close than the Na+ channels. Hence efflux of the K+ will result in hyperpolarization.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 128
Incorrect
-
Humoral immunity is a major defence against:
Your Answer:
Correct Answer: Viral infections
Explanation:Humoral immunity is provided by the neutralizing and non-neutralizing antibodies that are formed from the B lymphocytes. This form of immunity is most important in viral infection. Non-neutralizing antibodies increases phagocytosis of the infected cell and inhibit the ability of the virus to replicate.
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This question is part of the following fields:
- Immunology
- Medicine
-
-
Question 129
Incorrect
-
Question 130
Incorrect
-
Absolute refractory period in a cardiac action potential graph occurs during.
Your Answer:
Correct Answer: All of the above
Explanation:Absolute refractory period (ARP): the cell is completely unexcitable to a new stimulus and occurs from phase 0 – 2 i.e. depolarisation, early repolarisation and plateau phase.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 131
Incorrect
-
The small opening in the cochlea through which the upper scala vestibuli and lower scala tympani communicates is called the:
Your Answer:
Correct Answer: Helicotrema
Explanation:The helicotrema is the part of cochlear labyrinth where the scala tympani and the scala vestibuli meet.
-
This question is part of the following fields:
- Medicine
- Neurology
-
-
Question 132
Incorrect
-
Xanthines (for example Caffeine), exhibit their positive inotropic effect by:
Your Answer:
Correct Answer: Inhibiting the breakdown cAMP
Explanation:Xanthines exert their positive inotropic effect by inhibiting the breakdown of the cAMP resulting in stronger and sustained contraction.
-
This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 133
Incorrect
-
Concerning surface anatomy, where is the apex beat found?
Your Answer:
Correct Answer: 5th intercostal space mid clavicular line
Explanation:The location of the apex beat may vary but it is mostly found in the left 5th intercostal space 6 cm from the anterior median line or in the mid clavicular line.
-
This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 134
Incorrect
-
A 60 year old male presents with thickened patches of skin over his knuckles and extensor surfaces that are consistent with Gottron's papules. Results reveal an elevated creatine kinase. Diagnosis of dermatomyositis is suspected. Which of the following autoantibody is most specific for this condition?
Your Answer:
Correct Answer: Anti-Mi-2 antibodies
Explanation:Anti–Mi-2 antibodies are highly specific for dermatomyositis, but sensitivity is low; only 25% of patients with dermatomyositis demonstrate these antibodies. A positive antinuclear antibody (ANA) finding is common in patients with dermatomyositis, but is not necessary for diagnosis. Anti-Jo-1 antibodies are mostly associated with polymyositis. Anti Scl-70 antibodies and anti centromere antibodies are most commonly found in systemic scleroderma.
-
This question is part of the following fields:
- Connective Tissue
- Medicine
-
-
Question 135
Incorrect
-
The hepatic portal vein is a large vessel formed by which of the following veins?
Your Answer:
Correct Answer: All of the above
Explanation:The portal vein is usually formed by the confluence of the superior mesenteric and splenic veins and also receives blood from the inferior mesenteric, gastric, and cystic veins.
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This question is part of the following fields:
- Hepatobiliary
- Medicine
-
-
Question 136
Incorrect
-
In the olfactory pathway: Mitral cells project to five regions of the olfactory cortex. Which one of the following is not one of the five regions?
Your Answer:
Correct Answer: Posterior olfactory nucleus
Explanation:The olfactory system contains peripheral and central divisions which are connected by transduction structures. Peripheral division consists mainly of the nostrils, ethmoid bone, nasal cavity, and the olfactory epithelium. Olfactory neurons are receptor cells in the epithelium that detect odour molecules dissolved in the mucus and transmit information about the odour to the brain in a process called sensory transduction. Olfactory nerves and fibers transmit information about odours from the peripheral olfactory system to the central olfactory system of the brain. The main olfactory bulb transmits pulses to both mitral and tufted cells, which help determine odour concentration. These cells also note differences between highly similar odours and use that data to aid in later recognition. The cells are different with the mitral having low firing-rates and being easily inhibited by neighbouring cells, while tufted have high rates of firing and are more difficult to inhibit. The uncus houses the olfactory cortex which includes the piriform cortex, amygdala, olfactory tubercle, and para-hippocampal gyrus. Entorhinal cortex is an area of middle temporal lobe that has connection with the para-hippocampal gyrus.
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This question is part of the following fields:
- Medicine
- Neurology
-
-
Question 137
Incorrect
-
The Plateau phase in myocyte action potentials does all of the following except:
Your Answer:
Correct Answer: It allows early reactivation of the myocytes
Explanation:The presence of the plateau in the action potential causes ventricular contraction to last as much as 15 times longer in cardiac muscle as in skeletal muscle. The plateau phase which follows is unique to myocytes and results from a small, but sustained inward calcium current through L-type calcium channels lasting 200-400 ms. This calcium influx is caused by a combined increase in permeability of the cell and especially the sarcolemmal membranes to calcium. This plateau (refractory) phase prevents early reactivation of the myocytes and directly determines the strength of contraction.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 138
Incorrect
-
Inactive cellular marrow is called
Your Answer:
Correct Answer: Yellow marrow
Explanation:The two types of bone marrow are red marrow, which consists mainly of hematopoietic tissue, and yellow marrow, which is mainly made up of fat cells.
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This question is part of the following fields:
- Haematology
- Medicine
-
-
Question 139
Incorrect
-
The layers of the neocortex from the 1st to the 6th are arranged as follows:
Your Answer:
Correct Answer: Molecular, external granular, external pyramidal, internal granular, internal pyramidal, multiform
Explanation:The layers of neocortex from outermost to innermost include: the molecular, external granular layer, external pyramidal, internal granular, internal pyramidal and multiform layer.
-
This question is part of the following fields:
- Medicine
- Neurology
-
-
Question 140
Incorrect
-
Activation of baroreceptor reflex involves:
Your Answer:
Correct Answer: Short term regulation of systemic blood pressure
Explanation:Baroreceptors are found in the heart and the blood vessels. They are the carotid sinus and the aortic arch receptors and respond to the minute to minute change in the blood pressure i.e. a change in the pulsatile pressure and not to a change in the mean arterial pressure. If the pulse pressure decreases, the rate of firing of the receptors decreases, stimulating an increase in the heart rate and blood pressure. Mechanisms that regulate the long term blood pressure control include the renin-angiotensin-aldosterone mechanism.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 141
Incorrect
-
The growth promoting protein anabolic effects of insulin are mediated by:
Your Answer:
Correct Answer: Phosphatidylinositol 3-kinase
Explanation:Phosphatidylinositol 3-kinase or PI-3Ks are a group of enzymes which are involved in a number of different cellular functions. PI-3Ks interact with insulin and the insulin receptor substrate, regulating glucose uptake. They are an important element in the insulin signalling pathway.
-
This question is part of the following fields:
- Endocrinology
- Medicine
-
-
Question 142
Incorrect
-
Where is the myenteric plexus (Auerbach’s plexus) located in the GIT?
Your Answer:
Correct Answer: Between the outer longitudinal and middle circular muscle layers.
Explanation:A part of the enteric nervous system, the myenteric plexus exists between the longitudinal and circular layers of muscularis externa in the gastrointestinal tract. It is found in the muscles of the oesophagus, stomach, and intestine.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 143
Incorrect
-
The following play a role in regulation of intestinal iron absorption except:
Your Answer:
Correct Answer: Urinary iron excretion rate
Explanation:The human body’s rate of iron absorption appears to respond to a variety of interdependent factors, including total iron stores, dietary intake, the extent to which the bone marrow is producing new red blood cells, the concentration of haemoglobin in the blood, and the oxygen content of the blood. Classic examples of genetic iron overload includes hereditary hemochromatosis (HH) and the more severe disease juvenile hemochromatosis (JH).
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This question is part of the following fields:
- Haematology
- Medicine
-
-
Question 144
Incorrect
-
What is the function of secondary messengers?
Your Answer:
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
-
-
Question 145
Incorrect
-
The ATPase of parietal cells moves:
Your Answer:
Correct Answer: H+ into the gastric lumen in exchange for a k+
Explanation:ATPase of the parietal cell is also known as the proton pump, which moves H+ ions into the gastric lumen in exchange for K+ ions into the cell.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 146
Incorrect
-
Relaxation of the cardiac muscle at the actin-myosin cross bridges is initiated by binding of which molecule to the exposed site on the myosin.
Your Answer:
Correct Answer: ATP
Explanation:A crossbridge is a myosin projection, consisting of two myosin heads, that extends from the thick filaments. Each myosin head has two binding sites: one for ATP and another for actin. The binding of ATP to a myosin head detaches myosin from actin, thereby allowing myosin to bind to another actin molecule. Once attached, the ATP is hydrolysed by myosin, which uses the released energy to move into the cocked position whereby it binds weakly to a part of the actin binding site.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 147
Incorrect
-
A 20-year-old male presented to the clinic with a long term history of pins and needles sensation in both hands. He also has prognathism. He also gives a history of recent onset right upper quadrant pain after being started on a new medication for his condition. Which of the following medications acting on his endocrine system can be responsible for this adverse effect?
Your Answer:
Correct Answer: Octreotide
Explanation:The patient (known case of acromegaly) seems to have developed cholelithiasis (presenting with right upper quadrant pain) probably due to octreotide.It is a long-acting analogue of somatostatin which is released from D cells of the pancreas and inhibits the release of growth hormone, glucagon, and insulin.Uses- Acute treatment of variceal haemorrhage- Acromegaly- Carcinoid syndrome- Prevent complications following pancreatic surgery- VIPomas- Refractory diarrhoeaAdverse effectsGallstones (secondary to biliary stasis)Other options:- Bromocriptine – a dopamine agonist with side effects arising from its stimulation of the brain vomiting centre.- Desmopressin – predominantly used in patients with diabetes insipidus by increasing the presence of aquaporin channels in the distal collecting duct to increase water reabsorption from the kidneys. The main side effects include headache and facial flushing due to hypertension.- Metformin – mainly reduces hepatic gluconeogenesis in patients with type 2 diabetes, common side effects include diarrhoea, vomiting, and lactic acidosis- Levothyroxine – synthetic thyroxine used in patients with hypothyroidism, common side effects result from incorrect dosing and mimic the symptoms of hyperthyroidism.
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This question is part of the following fields:
- Medicine
- Pharmacology
-
-
Question 148
Incorrect
-
A 26-year-old student has been brought to the emergency department in a confused state. His friends report that he has been complaining of headaches for the past few weeks. He has a low-grade fever and on examination is noted to have abnormally pink mucosa. What is the most likely diagnosis?
Your Answer:
Correct Answer: Carbon monoxide poisoning
Explanation:Confusion and pink mucosae are typical features of CO poisoning.The patient often presents, most commonly with headaches, and other symptoms like malaise, nausea, and dizziness.Carbon monoxide (CO) poisoning, considered as the great imitator of other diseases as the patients present with a myriad of symptoms. The carbon monoxide diffuses rapidly across the pulmonary capillary membrane binding to the haem molecule with a very high affinity (240 times that of oxygen) forming carboxy-haemoglobin (COHb). Non-smokers have a baseline COHb of ,3% while smokers have a baseline COHb of 10-15%.Features of carbon monoxide toxicity- Headache: 90% of cases- Nausea and vomiting: 50%- Vertigo: 50%- Confusion: 30%- Subjective weakness: 20%- Severe toxicity: ‘pink’ skin and mucosae, hyperpyrexia, arrhythmias, extrapyramidal features, coma, deathTreatment:Use of Hyperbaric oxygen therapy (HBOT) for treating mild to moderate CO poisoning is not routine.The selection criteria for HBOT in cases of CO poisoning include:• COHb levels > 20-25%• COHb levels > 20% in pregnant patient • Loss of consciousness• Severe metabolic acidosis (pH <7.1)• Evidence of end-organ ischemia (e.g., ECG changes, chest pain, or altered mental status)
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This question is part of the following fields:
- Medicine
- Pharmacology
-
-
Question 149
Incorrect
-
Which one of the following features is least recognised in long-term lithium use?
Your Answer:
Correct Answer: Alopecia
Explanation:All the above side-effects, with the exception of alopecia, may be seen in patients taking lithium.
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This question is part of the following fields:
- Medicine
- Pharmacology
-
-
Question 150
Incorrect
-
A 28 year old female presents to the rheumatology clinic for review. She has a history of adult onset Still's disease and complains of joint pains and persistent skin rash despite undergoing treatment with methotrexate and etanercept. On examination, an erythematous macular rash and active synovitis is noted. CRP is high (95 mg/dl). Which of the following interventions would be most appropriate?
Your Answer:
Correct Answer: Anakinra
Explanation:Adult onset Still’s disease (AOSD) is an uncommon systemic inflammatory disease on the clinical spectrum of autoinflammatory disorders. Its presentation and clinical course may result in several well-differentiated phenotypes: from a systemic and highly symptomatic pattern to a chronic articular pattern. Overproduction of numerous pro-inflammatory cytokines is observed in AOSD. Anakinra, a human interleukin (IL)-1R antagonist, has recently been approved in the treatment of AOSD. Denosumab is a RANK ligand inhibitor used in the treatment of osteoporosis. Mepolizumab is used in the treatment of severe asthma with elevated eosinophils. There is some evidence to support the use of tocilizumab, an anti-IL6 monoclonal antibody in adult onset Still’s, but there is stronger data favouring the use of tocilizumab in the treatment of rheumatoid arthritis. Rituximab is usually reserved for patients who are unresponsive to anakinra.
-
This question is part of the following fields:
- Connective Tissue
- Medicine
-
-
Question 151
Incorrect
-
On which presynaptic receptor does noradrenalin act to inhibit noradrenalin secretion?
Your Answer:
Correct Answer: Α2 receptor
Explanation:Adregenic receptors are A1, A2, B1, B2, B3. Out of these, the function of the A2 receptor is inhibition of transmitter release including nor adrenalin and acetylcholine of the autonomic nervous system.
-
This question is part of the following fields:
- Medicine
- Neurology
-
-
Question 152
Incorrect
-
Stem cell characteristics include the following except
Your Answer:
Correct Answer: Differentiation and proliferation into progenitor cells committed to multiple cell lines
Explanation:The classical definition of a stem cell requires that it possess two properties:Self-renewal: the ability to go through numerous cycles of cell division while maintaining the undifferentiated state.Potency: the capacity to differentiate into specialized cell types. In the strictest sense, this requires stem cells to be either totipotent or pluripotent to be able to give rise to any mature cell type
-
This question is part of the following fields:
- Haematology
- Medicine
-
-
Question 153
Incorrect
-
The transport of the di- and tri-peptides into enterocytes is by:
Your Answer:
Correct Answer: H+ dependent peptide transporter 1
Explanation:Peptides longer that four amino acids are not absorbed. There is abundant absorption of di and tri peptidases in the small intestine. They are absorbed into the epithelial cell of the small intestine via a transporter called Peptide Transporter 1 by co transport with H+ ions.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 154
Incorrect
-
A 30-year-old woman is admitted for drainage of an abscess in her left forearm. She has revealed that she was regular heroin user and has stopped for the past few days. Clinical signs are pointing towards opioid withdrawal. What is the next step in managing this patient?
Your Answer:
Correct Answer: Give her 10 mg of methadone syrup and wait 60 min to determine its effect
Explanation:The next step in managing this patient is to give 10 mg and continue administering in 10 mg increments each hour until symptoms are under control.Methadone alleviates opioid withdrawal symptoms and reduces cravings. Methadone is useful for detoxification from longer-acting opioids such as morphine or methadone itself.Methadone should be used with caution if the patient has:Respiratory deficiencyAcute alcohol dependenceHead injuryTreatment with monoamine oxidase inhibitors (MAOIs)Ulcerating colitis or Crohn’s diseaseSevere hepatic impairmentThe dose must be reviewed on a daily basis and adjusted based upon how well the symptoms are controlled and the presence of side effects. The greater the dose of opioids used by the patient, the greater the dose of methadone required to control withdrawal symptoms. To avoid the risk of overdose in the first days of treatment The recommended dosing of methadone is 30mg in two doses of 15mg morning and evening.It is important to note that a methadone dose equivalent to what the patient reports they are taking should never be given. It is rare to need more than 40 mg per 24 hours: beware of overdosing which can lead to respiratory arrest.
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This question is part of the following fields:
- Medicine
- Pharmacology
-
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Question 155
Incorrect
-
Direct conduction from the atrium to the ventricles is prevented by:
Your Answer:
Correct Answer: Annulus fibrosus
Explanation:The annulus fibrosus disconnects the syncytium complex. The atria are rapidly activated however the activation peters out when the insulating layer-the annulus fibrosus-is reached.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 156
Incorrect
-
Which statement regarding fever is correct:
Your Answer:
Correct Answer: Body temperature is regulated is by a centre in the floor of the third ventricle
Explanation:The hypothalamus is located on the floor of the third ventricle and is the centre of regulation of body temperature. It uses a set point to regulate other body systems as well. Diurnal variation of temperature is not seen in humans. the principal mediator of fever is interleukin I, although interferon alfa also plays a role. Fever can cause rhabdomyolysis or muscle breakdown
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This question is part of the following fields:
- Infectious Diseases
- Medicine
-
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Question 157
Incorrect
-
Platelets are stored in this body organ.
Your Answer:
Correct Answer: Spleen
Explanation:Megakaryocyte and platelet production is regulated by thrombopoietin. Each megakaryocyte produces between 1,000 and 3,000 platelets during its lifetime. An average of 1011 platelets are produced daily in a healthy adult. Reserve platelets are stored in the spleen, and are released when needed by splenic contraction induced by the sympathetic nervous system.
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This question is part of the following fields:
- Haematology
- Medicine
-
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Question 158
Incorrect
-
Calcium needed for cardiac muscle contraction is made available during which phase of the action potential?
Your Answer:
Correct Answer: 2
Explanation:It is made available during the plateau phase of the action potential i.e. phase 2. During the plateau phase of the action potential, Calcium from the extracellular fluid enters through the L type of calcium channels. This entry triggers the release of more calcium from the sarcoplasmic reticulum via the ryanodine receptors.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 159
Incorrect
-
Which of the following statements is not true about mitochondrial chromosomes?
Your Answer:
Correct Answer: Mitochondrial chromosomes play no role in the transmission of disease from generation to generation.
Explanation:All the above mentioned statements are true except that mitochondrial DNA is passed from the mother to the child. If the child inherits the defective mitochondrial gene it will manifest some form of the disease. Commonly inherited diseases related to mitochondrial abnormality are Leber hereditary optic neuropathy and myoclonic epilepsy with ragged red fibers (MERRF).
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This question is part of the following fields:
- Genetics
- Medicine
-
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Question 160
Incorrect
-
von Willebrand factor stabilises which clotting factor?
Your Answer:
Correct Answer: Factor VIII
Explanation:Von Willebrand factor’s primary function is binding to other proteins, in particular factor VIII, and it is important in platelet adhesion to wound sites. It is not an enzyme and, thus, has no catalytic activity. Factor VIII degrades rapidly when not bound to vWF. Factor VIII is released from vWF by the action of thrombin.
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This question is part of the following fields:
- Haematology
- Medicine
-
-
Question 161
Incorrect
-
Which neurotransmitter is released from the postganglionic fibers in the sympathetic division?
Your Answer:
Correct Answer: Noradrenalin
Explanation:Noradrenalin Is the neurotransmitter that is released from the postganglionic fibers of the sympathetic division. It is stored in granules at the sympathetic knobs. It Is a methyl derivative.
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This question is part of the following fields:
- Medicine
- Neurology
-
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Question 162
Incorrect
-
Which of the following isoforms of Nitric oxide synthase (NOS) is found in endothelial cells?
Your Answer:
Correct Answer: Nos 3
Explanation:There are only 3 isoforms:NOS 1: found in nervous systemNOS 2: in macrophages and other immune cellsNOS 3: In endothelial cells
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 163
Incorrect
-
Which of the following is an example of a ketone body?
Your Answer:
Correct Answer: Acetoacetate
Explanation:Ketone bodies are three water-soluble molecules (acetoacetate, beta-hydroxybutyrate, and their spontaneous breakdown product, acetone) that are produced by the liver from fatty acids during periods of low food intake (fasting), carbohydrate restrictive diets, starvation, prolonged intense exercise, alcoholism or in untreated (or inadequately treated) type 1 diabetes mellitus.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 164
Incorrect
-
The postextrasystolic potentiation of myocardial contractility is due to:
Your Answer:
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 165
Incorrect
-
Of the daily production of CSF, the vast majority is produced in the:
Your Answer:
Correct 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 166
Incorrect
-
Regarding CSF:
Your Answer:
Correct Answer: Disruption of arachnoid villi function results in a communicating hydrocephalus
Explanation:In normal adults CSF volume is around 125ml to 150ml. Turnover of the entire volume of cerebrospinal fluid is about 3 to 4 times a day. Composition of CSF is similar to that of plasma except that CSF is nearly protein-free compared with plasma and has different electrolyte levels. Blockage of the foramina causes an obstructive or non-communicating hydrocephalus. Communicating hydrocephalus or non-obstructive hydrocephalus is caused by impaired CSF reabsorption in the absence of any CSF flow obstruction.
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This question is part of the following fields:
- Medicine
- Neurology
-
-
Question 167
Incorrect
-
What is the function of cytotoxic T cells?
Your Answer:
Correct Answer: Kill by inserting perforins and by initiating apoptosis
Explanation:Cytotoxic T cells, once activated, approach the infected cell, insert perforins and release granzymes inducing apoptosis.
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This question is part of the following fields:
- Immunology
- Medicine
-
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Question 168
Incorrect
-
Regarding glomus cells, which of the following is true?
Your Answer:
Correct Answer: Contain catecholamines
Explanation:The carotid body detects changes in the composition of arterial blood flowing through it, mainly the partial pressure of oxygen, but also of carbon dioxide. Furthermore, it is also sensitive to changes in pH and temperature.The carotid body is made up of two types of cells, called glomus cells: Glomus type I/chief cells release a variety of neurotransmitters, including acetylcholine, ATP, and dopamine that trigger EPSPs in synapsed neurons leading to the respiratory centre.Glomus type II/sustentacular cells resemble glia, express the glial marker S100 and act as supporting cells.
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This question is part of the following fields:
- Medicine
- Respiratory
-
-
Question 169
Incorrect
-
Concerning coronary arteries, what is the net effect of B2 stimulation on the heart (e.g. Running athlete)?
Your Answer:
Correct Answer: Vasodilation via production of metabolites
Explanation:The coronary arterioles contain α-adrenergic receptors, which cause vasoconstriction, and β-adrenergic receptors, which cause vasodilation. Activity in the noradrenergic nerves to the heart and injections of norepinephrine cause coronary vasodilation. However, norepinephrine also increases the heart rate and the force of cardiac contraction, and the vasodilation is due to production of vasodilator metabolites in the myocardium secondary to the increase in its activity. As exercise has the same effect as sympathetic stimulation, it will result in vasodilation.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 170
Incorrect
-
The brainstem reticular formation, consists of which important control system responsible for consciousness and sleep?
Your Answer:
Correct Answer: RAS reticular activating system
Explanation:The reticular formation is a set of interconnected nuclei that are located along the brainstem. Reticular activating system (RAS) is a set of connected nuclei in the brain that is responsible for regulating wakefulness and sleep wake transitions and is the most influential component in the reticular formation.
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This question is part of the following fields:
- Medicine
- Neurology
-
-
Question 171
Incorrect
-
Cell membrane proteins may act as:
Your Answer:
Correct Answer: All of the options
Explanation:Membrane proteins perform a variety of functions including:Membrane receptor proteins relay or carry signals between the cell’s internal and external environments.Transport proteins move molecules and ions (ionic channels) across the membrane. Membrane enzymes may have many activities, such as oxidoreductase, transferase or hydrolase andCell adhesion molecules
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This question is part of the following fields:
- Cell Biology
- Medicine
-
-
Question 172
Incorrect
-
Which of the following forms one of the characteristic and functional cells making up the anterior pituitary gland?
Your Answer:
Correct 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
-
-
Question 173
Incorrect
-
Which afferent information is carried by the dorsal column?
Your Answer:
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
-
-
Question 174
Incorrect
-
Which of the following has the shortest duration:
Your Answer:
Correct Answer: Atrial systole
Explanation:Atrial systole: 0.1s
Atrial diastole: around 0.4s
Ventricular diastole: 0.4-0.53s
Ventricular systole: 0.27s
PR interval: 0.12-0.2 s
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 175
Incorrect
-
According to the Vaughan William's classification of antiarrhythmic agents, lidocaine is a:
Your Answer:
Correct Answer: Class Ib agent
Explanation:Lidocaine is an example of class IB antiarrhythmics.The Vaughan-Williams classification of antiarrhythmicsI: Membrane stabilizing agentsIA: Quinidine, Procainamide, DisopyramideIB: Lidocaine, MexiletineIC: Propafenone, Flecainide II: β blockers – Propranolol, EsmololIII: Agents widening AP – Amiodarone, Dronedarone, Dofetilide, Ibutilide, SotalolIV: Calcium channel blockers – Verapamil, DiltiazemV: Miscellaneous – Digoxin, adenosine, magnesium
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This question is part of the following fields:
- Medicine
- Pharmacology
-
-
Question 176
Incorrect
-
An 81-year-old male presented to the emergency department following a fall at home. He was diagnosed with osteoporosis about five years ago. He presently complains of significant low back pain. A lumbar spine X-ray was suggestive of a fractured lumbar vertebra. A subsequent MRI scan of the lumbosacral spine revealed a new L3 burst fracture with no evidence of cord compression. A neurosurgical consult was sought and conservative management was planned accordingly in the form of pain control, physiotherapy, and mobilization (as allowed by the pain). He also has been diagnosed with chronic renal disease (stage IV) with a creatinine clearance of 21ml/min, he was started on a Buprenorphine patch. Which of the following opioids would be safest to use for his breakthrough pain?
Your Answer:
Correct Answer: Oxycodone
Explanation:Oxycodone is a safer opioid to use in patients with moderate to end-stage renal failure.Active metabolites of morphine accumulate in renal failure which means that long-term use is contraindicated in patients with moderate/severe renal failure. These toxic metabolites can accumulate causing toxicity and risk overdose. Oxycodone is mainly metabolised in the liver and thus safer to use in patients with moderate to end-stage renal failure with dose reductions.Adverse effects:Constipation is the most common overall side effect. Others include: asthenia, dizziness, dry mouth, headache, nausea, pruritus, etc. Medications in renal failure:Drugs to be avoided in patients with renal failureAntibiotics: tetracycline, nitrofurantoinNSAIDsLithiumMetforminDrugs that require dose adjustment:Most antibiotics including penicillin, cephalosporins, vancomycin, gentamicin, streptomycinDigoxin, atenololMethotrexateSulphonylureasFurosemideOpioidsRelatively safe drugs:Antibiotics: erythromycin, rifampicinDiazepamWarfarin
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This question is part of the following fields:
- Medicine
- Pharmacology
-
-
Question 177
Incorrect
-
Which of the following may be a feature of primary hyperaldosteronism?
Your Answer:
Correct Answer: Muscular weakness
Explanation:Primary hyperaldosteronism or Conn’s syndrome is characterised by hypertension which may cause poor vision or headaches. Occasionally there may be muscular weakness, muscle spasms, tingling sensations, or excessive urination. Complications include cardiovascular disease such as stroke, myocardial infarction, kidney failure, and abnormal heart rhythms.
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This question is part of the following fields:
- Endocrinology
- Medicine
-
-
Question 178
Incorrect
-
Where is leptin synthesized and secreted?
Your Answer:
Correct Answer: White adipose tissue
Explanation:Leptin is a hormone that helps regulate food intake and energy expenditure. It is synthetized by white adipose tissue and the gastric mucosa. It works by inhibiting the sensation of hunger, therefore, it opposes the actions of ghrelin, also known as the hunger hormone.
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This question is part of the following fields:
- Endocrinology
- Medicine
-
-
Question 179
Incorrect
-
A 42 year old female presents with morning stiffness that usually takes an hour to settle and a one year history of intermittent pain and swelling of the small joints of her hands. Examination reveals symmetric soft tissue swelling over the PIP and MCP joints and rheumatoid nodules on the elbows. There is also an effusion of both wrists. Lab results are positive for rheumatoid factor. X-ray of the wrists and hands shows erosions and bony decalcification. NSAIDs are started and the patient is referred to a rheumatologist for consideration of DMARD. Previous history is significant for TB. Which of the following should be avoided?
Your Answer:
Correct Answer: Infliximab
Explanation:Anti-TNF-α therapy is effective for patients with arthritis but it can oftentimes lead to the reactivation of latent TB. Hence it should be used with great caution in patients with a past history of TB or current infection.
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This question is part of the following fields:
- Connective Tissue
- Medicine
-
-
Question 180
Incorrect
-
H+ ions used in the production of acid by parietal cells is produced with the help of which enzyme?
Your Answer:
Correct Answer: Carbonic anhydrase ii
Explanation:Carbonic anhydrase enzyme catalyses the rapid interconversion of carbon dioxide and water to bicarbonate and protons (or vice versa). This is a reversible reaction that takes place in the gastric parietal cells.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 181
Incorrect
-
Intermediate filaments achieve cell to cell contact via:
Your Answer:
Correct Answer: Desmosomes
Explanation:At the plasma membrane, some keratins interact with desmosomes (cell-cell adhesion) and hemidesmosomes (cell-matrix adhesion) via adapter proteins.
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This question is part of the following fields:
- Cell Biology
- Medicine
-
-
Question 182
Incorrect
-
Water hammer pulse is found in:
Your Answer:
Correct Answer: Aortic insufficiency
Explanation:Watson’s water hammer pulse is the medical sign which describes a pulse that is bounding and forceful, rapidly increasing and subsequently collapsing, as if it were the sound of a water hammer that was causing the pulse. A water hammer was a Victorian toy in which a tube was half filled with fluid, the remainder being a vacuum. The child would invert and reinvert the tube; each time the impact of the fluid at each end would sound like a hammer blow. This is associated with increased stroke volume of the left ventricle and decrease in the peripheral resistance leading to the widened pulse pressure of aortic regurgitation.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 183
Incorrect
-
Which of the following is true of the Natriuretic hormones?
Your Answer:
Correct Answer: They are released in response to hypervolemia
Explanation:Natriuretic hormones are vasodilators released in response to hypervolemia.
Natriuretic hormones (NH) include three groups of compounds: the natriuretic peptides NPs (ANP, BNP and CNP), the gastrointestinal peptides (guanylin and uroguanylin), and endogenous cardiac steroids. These substances induce the kidney to excrete sodium and therefore participate in the regulation of sodium and water homeostasis, blood volume, and blood pressure (BP). In addition to their peripheral functions, these hormones act as neurotransmitters or neuromodulators in the brain.
Atrial natriuretic peptide (ANP) plays a crucial role in blood pressure regulation by inducing natriuresis and diuresis in the kidney, inhibiting renin secretion, aldosterone production, and promoting vasorelaxation. Two paracrine factors derived from endothelial cells play important roles in modulating ANP secretion. Endothelin, a potent vasoconstrictor, stimulates ANP secretion and augments stretch induced ANP secretion. The dramatic increase in ANP release produced by cardiac ischemia appears to be mediated in part by endothelin. Nitric oxide (NO), an important vasodilator, is also produced by endothelial cells and inhibits ANP secretion.
Brain natriuretic peptide (BNP) shares ANP’s receptor but is primarily associated with antifibrotic effects in ventricular remodeling, serving as a biomarker for heart failure and myocardial infarction.
C-type natriuretic peptide (CNP) acts locally in an autocrine/paracrine manner, exerting potent cardiovascular effects, including vasorelaxation and vascular remodeling post-injury. NPs also demonstrate diverse effects beyond cardiovascular and renal systems, such as bronchodilation, anti-inflammatory actions, and metabolic effects on adipose tissue and long bones.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 184
Incorrect
-
A 49 year old female presents to the clinic complaining of pain in her left elbow that is localized to the left lateral epicondyle. She has spent the weekend painting her house. A diagnosis of lateral epicondylitis is suspected. The pain would characteristically worsen on which of the following movements?
Your Answer:
Correct Answer: Resisted wrist extension with the elbow extended
Explanation:Lateral epicondylitis (tennis elbow) is an overuse injury of the hand and finger extensor tendons that originate in the lateral humeral epicondyle that occurs following repeated or excessive pronation/supination and extension of the wrist (e.g., in racquet sports). Clinical features include pain and tenderness over the lateral epicondyle and along extensor muscles, thickening of the tendons. The examiner holds the patient’s hand with the thumb placed over the lateral epicondyle – The patient makes a fist, supinates the forearm, deviates radially, and extends the fist against the examiner’s resistance which results in pain over the lateral epicondyle. Conservative treatment includes rest, physiotherapy and orthotic braces. If this fails corticosteroids and lidocaine injections are employed. Surgery is indicated in patients with persistent symptoms despite 6 months of conservative treatment. Excision of abnormal tendon tissue; longitudinal incisions (tenotomies) in scarred and fibrotic areas to promote healing.
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This question is part of the following fields:
- Connective Tissue
- Medicine
-
-
Question 185
Incorrect
-
Which of the following stimulates glucagon release?
Your Answer:
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
-
-
Question 186
Incorrect
-
Approximately what percentage of the world is infected with tuberculosis:
Your Answer:
Correct Answer: 25%
Explanation:The WHO report states that about one-quarter of the world’s population is infected with Mycobacterium tuberculosis, the bacterium that causes tuberculosis. This means approximately 25% of people globally have latent TB infection, which can potentially progress to active TB disease.
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This question is part of the following fields:
- Infectious Diseases
- Medicine
-
-
Question 187
Incorrect
-
Which of the following statements is most suitable to describe necrosis?
Your Answer:
Correct Answer: Significant inflammatory response
Explanation:Necrosis is the death of most or all of the cells in an organ or tissue due to disease, injury, or failure of the blood supply. Cellular death due to necrosis does not follow the (regulated) apoptotic signal transduction pathway, but rather various receptors are activated, and result in the loss of cell membrane integrity and an uncontrolled release of products of cell death into the extracellular space. This initiates in the surrounding tissue an inflammatory response which attracts leukocytes and nearby phagocytes which eliminate the dead cells by phagocytosis.
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This question is part of the following fields:
- Cell Biology
- Medicine
-
-
Question 188
Incorrect
-
Which segment of the nephron is impermeable to water?
Your Answer:
Correct Answer: Ascending limb of Henle
Explanation:Considerable differences aid in distinguishing the descending and ascending limbs of the loop of Henle. The descending limb is permeable to water and noticeably less permeable to salt, and thus only indirectly contributes to the concentration of the interstitium. Unlike the descending limb, the thin ascending limb is impermeable to water, a critical feature of the counter current exchange mechanism employed by the loop.
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This question is part of the following fields:
- Medicine
- Renal
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Question 189
Incorrect
-
To which protein is T3 mostly bound in the serum?
Your Answer:
Correct Answer: Thyroxin-binding globulin
Explanation:In a normal person, approximately 0.03 per cent of the total serum T4, and 0.3 per cent of the total serum T3 are present in free or unbound form. The major serum thyroid hormone-binding proteins are: 1) thyroxine-binding globulin [TBG or thyropexin], 2) transthyretin [TTR or thyroxine-binding prealbumin (TBPA)], and 3) albumin (HAS, human serum albumin). TBG has highest affinity for T4, which is 50-fold higher than that of TTR and 7,000-fold higher that of HSA. As a result TBG binds 75% of serum T4, while TTR and HSA binds only 20% and Albumin 5%, respectively.
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This question is part of the following fields:
- Endocrinology
- Medicine
-
-
Question 190
Incorrect
-
During exercise, a man consumes 2L O2/min, his arterial 02 content is 190 ml/l and the 02 content of his mixed venous blood is 130ml/l. His cardiac output is approximately:
Your Answer:
Correct Answer: 33l/min
Explanation:In Fick’s original method, the following variables are measured:VO2, oxygen consumption in ml of pure gaseous oxygen per minute. This may be measured using a spirometer within a closed rebreathing circuit incorporating a CO2 absorberCa, the oxygen concentration of blood taken from the pulmonary vein (representing oxygenated blood)Cv, the oxygen concentration of blood from an intravenous cannula (representing deoxygenated blood)From these values, we know that:VO2 = (CO x Ca) – (CO x Cv)where CO = Cardiac Output, Ca = Oxygen concentration of arterial blood and Cv = Oxygen concentration of mixed venous blood.This allows us to sayCO = VO2/{Ca – Cv}and hence calculate cardiac output.Therefore CO = 2/(0.190-0.130) = 33l/minNote that (Ca – Cv) is also known as the arteriovenous oxygen difference.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 191
Incorrect
-
A 62 year old man arrives at the clinic with a history of cough and intermittent haemoptysis for the last 3 months. He has a 50 pack year smoking history and is currently waiting for bronchoscopy to assess a left lower lobe collapse. The patient also has a marked muscle weakness and wasting of proximal muscles of his shoulders and pelvic girdle. His wife states that lately he has been unable to eat solids. Which of the following statements would be true regarding this scenario?
Your Answer:
Correct Answer: He may have a photosensitive facial rash
Explanation:The patient has presented with signs of small cell lung cancer. The associated proximal muscle weakness is most probably due to dermatomyositis which occurs as a paraneoplastic syndrome associated with lung carcinoma. In most cases, the first symptom is a distinctive skin rash on the face, eyelids, chest, nail cuticle areas, knuckles, knees or elbows. The rash is patchy and usually a bluish-purple colour. Corticosteroids are helpful in the management of the cutaneous changes and muscle weakness.
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This question is part of the following fields:
- Connective Tissue
- Medicine
-
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Question 192
Incorrect
-
A 16 year old previously well male presents with a 4 day history of fever, lethargy and a generalized macular rash. There is no significant previous medical history and the patient has not travelled abroad either. Vitals are as follows: Temp: 38.5BP: 125/75mmHgPulse: 100/min On auscultation the chest was clear and no heart murmur was heard. Examination also reveals a non blanching widespread macular rash over the chest and abdomen. There is swelling of interphalangeal joints of both hands and feet associated with mild tenderness. Lymph nodes are palpable over the supraclavicular, axillary and inguinal areas. Abdominal examination reveals palpable mass on both right and left hypochondrium. Lab results are given below:Haemoglobin (Hb) 13.5 g/dlWhite cell count (WCC) 14.0 × 109/lPlatelets 380 × 109/lSodium 145 mmol/lPotassium 4.8 mmol/lCreatinine 89 μmol/lRheumatoid factor NegativeAntinuclear antibody NegativeAnti-dsDNA NegativeASO titre Not detectedElectrocardiogram (ECG) Sinus rhythmWhat is the most likely underlying diagnosis?
Your Answer:
Correct Answer: Systemic Still’s disease
Explanation:People with Systemic Juvenile Idiopathic Arthritis (also known as Stills disease) can have recurrent fevers, a macular rash, joint pain, joint deformities, an enlarged liver and/or spleen, and can occasionally have polyserositis, lung involvement or pericardial effusions. Rheumatoid factor and antinuclear antibodies are usually negative. Treatment is with non-steroidal anti-inflammatory drugs (NSAIDs) and the prognosis is better than for adult rheumatoid arthritis.In pauciarticular Still’s disease, antinuclear antibodies are present. Large joints are affected and most patients develop classic features of seronegative spondylarthritis.
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This question is part of the following fields:
- Connective Tissue
- Medicine
-
-
Question 193
Incorrect
-
What are the major motor proteins that interact with microtubules?
Your Answer:
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
-
-
Question 194
Incorrect
-
Regarding the innervation of the cerebral blood vessels, postganglionic sympathetic neurons have their cell bodies in the:
Your Answer:
Correct Answer: Superior cervical ganglia
Explanation:The superior cervical ganglion (SCG) is a part of autonomic system which plays a major role in maintaining homeostasis of the body. This ganglion innervates structures in the head and neck and is the largest and the most superiorly located ganglion. The SCG provides sympathetic innervation to structures within the head, including the pineal gland, the blood vessels in the cranial muscles and the brain, the choroid plexus, the eyes, the lacrimal glands, the carotid body, the salivary glands, and the thyroid gland. The postganglionic axons of the SCG innervate the internal carotid artery and form the internal carotid plexus. The internal carotid plexus carries the postganglionic axons of the SCG to the eye, lacrimal gland, mucous membranes of the mouth, nose, and pharynx, and numerous blood-vessels in the head.
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This question is part of the following fields:
- Medicine
- Neurology
-
-
Question 195
Incorrect
-
Choose the standard method for comparing distributions in data sets (such as between the expected frequency of an event and the observed frequency of an event) from the list of options.
Your Answer:
Correct Answer: Chi squared (X²) test
Explanation:The Chi-squared test evaluates if two variables are related. The other statistical tests mentioned do not perform this function.
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This question is part of the following fields:
- Medicine
- Research Skills
-
-
Question 196
Incorrect
-
Which one of the following have not been shown to improve mortality in patients with chronic heart failure?
Your Answer:
Correct Answer: Furosemide
Explanation:A number of drugs have been shown to improve mortality in patients with chronic heart failure:
- ACE inhibitors (SAVE, SOLVD, CONSENSUS)
- spironolactone (RALES)
- beta-blockers (CIBIS)
- hydralazine with nitrates (VHEFT-1)
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 197
Incorrect
-
In RFLP (restriction fragment length polymorphism), the DNA fragments are separated by length through a process known as:
Your Answer:
Correct Answer: Agarose gel electrophoresis
Explanation:Samples of DNA from individuals are broken into pieces by restriction enzymes and the fragments are separated according to their lengths via gel electrophoresis. Although now largely obsolete due to the rise of inexpensive DNA sequencing technologies, RFLP analysis was the first DNA profiling technique inexpensive enough to see widespread application.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 198
Incorrect
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A 53-year-old female teacher asks about hormone replacement therapy (HRT). What is the most compelling indication for starting HRT?
Your Answer:
Correct Answer: Control of vasomotor symptoms such as flushing
Explanation:Hormone replacement therapy (HRT) involves the use of a small dose of oestrogen, combined with a progestogen (in women with a uterus), to help alleviate menopausal symptoms. The main indication is the control of vasomotor symptoms. The other indications, such as reversal of vaginal atrophy and prevention of osteoporosis, should be treated with other agents as first-line therapies.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 199
Incorrect
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Which of the following is the most common causative organism in infective endocarditis?
Your Answer:
Correct Answer: Streptococcus viridans
Explanation:Viridans Alpha-haemolytic streptococci, that are present in the mouth are the most frequently isolated microorganisms when the infection is acquired in a community setting. In contrast, Staphylococcus blood stream infections are frequently acquired in a health care setting where they can enter the blood stream through procedures that cause break in the integrity of skin like surgery, catheterisation or during access of long term indwelling catheters or secondary to intravenous injection of recreational drugs.Prosthetic valve endocarditis is commonly caused by Staphylococcus epidermidis as it is capable of growing as a biofilm on plastic surfaces
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 200
Incorrect
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In which phase do chromosomes in the nucleus become condensed into well-defined chromosomes?
Your Answer:
Correct Answer: Metaphase
Explanation:Prophase begins when the nucleus envelope disintegrates and the chromosomes start to condense. The chromosomes consist of two sister chromatids that are joined at a constriction known as centromere. When the cell reaches the metaphase the chromosomes are completely condensed and ready to align on the equatorial plate
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This question is part of the following fields:
- Genetics
- Medicine
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SESSION STATS - PERFORMANCE PER SPECIALTY
