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Question 1
Correct
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Cells mediating innate immunity include:
Your Answer: Natural killer cells
Explanation:Natural killer cells have features of both innate and adaptive immunity. They play an important part in defence against tumours and viruses. They are non specific and do not generate immunological memory
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This question is part of the following fields:
- Immunology
- Medicine
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Question 2
Correct
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Excitation-contraction coupling in cardiac muscle involves all of the following except:
Your Answer: Binding of Ca2+ to calmodulin
Explanation:In the excitation contraction coupling model, an action potential is transmitted to the fibrils of a fiber through the T tubule system. It triggers the release of Ca 2+ from the terminal cisterns. Depolarization of the T tubules activates the sarcoplasmic reticulum through the dihydropyridine receptors. These are voltage gates calcium channels. Calcium binds to calmodulin during contraction of the smooth muscle and not the cardiac muscles.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 3
Correct
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Southern Blotting and DNA probes:
Your Answer: DNA fragments are separated by gel electrophoresis and transferred onto membrane sheets in southern blotting
Explanation:A Southern blot is a method used in molecular biology for detection of a specific DNA sequence in DNA samples. Southern blotting combines transfer of electrophoresis-separated DNA fragments to a filter membrane and subsequent fragment detection by probe hybridization. The other forms of blotting involve the use of RNA and proteins.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 4
Incorrect
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Osteopetrosis occurs as a result of a defect in:
Your Answer: Osteoblast function
Correct Answer: Osteoclast function
Explanation:It is a metabolic bone disease caused by defective osteoclastic resorption of immature bone. Osteopetrosis is also known as marble bone disease. Osteoclasts are unable to adequately acidify bone matrix. Impaired bone resorption leads to overly dense bone that is more likely to fracture. It is usually treated with bone marrow transplant and high dose calcitriol.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 5
Incorrect
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Normal parents have a child with a recessive condition, Tay Sachs. The chance of them having a normal child is?
Your Answer: 25%
Correct Answer: 75%
Explanation:The chance for normal parents having a child with a recessive disease is 1:4 or 25%. As both the parents are heterozygous for this condition. They have a 3:4 chance of having a normal child or 75%.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 6
Correct
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In a 70 kg male, the approximate volumes (litres) of water in the different compartments mentioned (intracellular, interstitial, vascular) are:
Your Answer: 28l, 14l, 3.5l
Explanation:In a 70kg male, approximately 60% (42 L) of the total body weight is composed of water divided proportionally in the following compartments:Intracellular fluid (ICF) – Around 67% (28 L) of total body water.Extracellular fluid (ECF) – Approximately 33% (14 L) of the total body fluid. The fluid in the intravascular compartment is about 3 L and is generally about 25% of the volume of ECF.
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This question is part of the following fields:
- Medicine
- Renal
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Question 7
Correct
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Question 8
Correct
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Carotid bodies...
Your Answer: Are located near the bifurcation of the carotid arteries bilaterally
Explanation:The carotid body is a small cluster of chemoreceptors and supporting cells located near the fork (bifurcation) of the carotid artery (which runs along both sides of the throat).The carotid body detects changes in the composition of arterial blood flowing through it, mainly the partial pressure of oxygen, but also of carbon dioxide. Furthermore, it is also sensitive to changes in pH and temperature. Carotid bodies trigger an action potential through the afferent fibers of the glossopharyngeal nerve,
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This question is part of the following fields:
- Medicine
- Respiratory
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Question 9
Incorrect
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Cold receptors are likely to be active at the following temperatures except?
Your Answer: 19 °C
Correct Answer: 39 °C
Explanation:Cold and Menthol receptor 1 (CMR1) is a protein that in humans is encoded by TRPM8 gene. It is primarily responsible for the detection of temperatures ranging from 8-28 C. It is an ion channel which upon activation causes the influx of Na+ and Ca+ ions into the cell that leads to the depolarization and generation of an action potential.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 10
Incorrect
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In terms of relative steroid potency, how much prednisone is equivalent to 100mg hydrocortisone?
Your Answer: 100mg
Correct Answer: 25mg
Explanation:Different corticosteroids have varying degrees of potency. 1 mg of prednisone is equivalent to 4 mg of hydrocortisone. Therefore, 25 mg of prednisone are equivalent to 100 mg of hydrocortisone.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 11
Correct
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Renin is secreted by which of the following cells?
Your Answer: Juxtaglomerular cells
Explanation:The juxtaglomerular cells are cells in the kidney that synthesize, store, and secrete the enzyme renin. They are specialized smooth muscle cells mainly in the walls of the afferent arterioles, and some in the efferent arterioles, that deliver blood to the glomerulus.
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This question is part of the following fields:
- Medicine
- Renal
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Question 12
Incorrect
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Which of the following is a characteristic clinical finding of opioid poisoning?
Your Answer: Deep respiration
Correct 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 13
Incorrect
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Which of the following would be the most appropriate treatment (leaving out the current NICE guidelines) for a 29 year old man with erythrodermic psoriasis and arthritis mutilans involving several digits of both hands?
Your Answer: Prednisolone
Correct Answer: Etanercept
Explanation:TNF-alpha inhibitors are known to ameliorate the symptoms and disease activity of Arthritis mutilans (a rare and severe form of psoriatic arthritis), by disabling the cytokines that are involved in inflammation and joint destruction. From the mentioned choices, this would be the most effective option. Methotrexate is the most commonly used DMARD, followed by sulfasalazine used in mild to moderate forms of psoriatic arthritis but has not shown much efficacy in arthritis mutilans. Phototherapy, narrowband UVB light therapy can be very effective in clearing skin lesions.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 14
Correct
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A 70-year-old male with advanced COPD currently on treatment with salbutamol (as required) presents for review. After a complete history and examination, you conclude that he requires to be stepped up in his inhalational therapy. The decision to add tiotropium bromide to his regime was taken. Which of the following best describe the mechanism of action of tiotropium?
Your Answer: It is a long-acting anticholinergic agent
Explanation:Tiotropium is a specific long-acting antimuscarinic agent indicated as maintenance therapy for patients with COPD (chronic obstructive pulmonary disease). It should be used cautiously in patients with narrow-angle glaucoma, prostatic hyperplasia or bladder neck obstruction.The most frequently encountered adverse effects of tiotropium include pharyngitis, bronchitis, sinusitis, dry mouth, cough, and headaches. Paradoxical bronchospasm may also occur as a rare side-effect. Dry mouth occurs in up to 14% of patients taking tiotropium, in keeping with its anticholinergic profile. Rarer side-effects include tachycardia, blurred vision, urinary retention, and constipation.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 15
Correct
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Which of the following intercellular connections is important in endothelial barrier function?
Your Answer: Tight junctions
Explanation:Tight junctions surround the apical margins of the epithelial cells such as in the intestinal mucosa and the choroid plexus. They are also important to the endothelial barrier function. They are made up of ridges that adhere to each other strongly at the cell junction, obliterating the space completely between the cells.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 16
Incorrect
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In adults, the major site of haematopoiesis is?
Your Answer: The spleen
Correct Answer: The axial skeleton
Explanation:Bone marrow is the flexible tissue in the interior of bones. In humans, red blood cells are produced by cores of bone marrow in the heads of long bones.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 17
Incorrect
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Choose the correct answer: The interposed nuclei…
Your Answer: All of the above
Correct Answer: Are the emboliform and globose nuclei in the paravermis
Explanation:The interposed nuclei are a part of deep cerebellar complex and are composed of the globose nucleus and the emboliform nucleus. It receives afferent fibers from the anterior lobe of the cerebellum and sends output via the superior cerebellar peduncle to the red nucleus.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 18
Incorrect
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Question 19
Correct
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Platelets are stored in this body organ.
Your 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 20
Incorrect
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Type 2 hypersensitivity is mediated by:
Your Answer: IgE and mast cells
Correct Answer: IgG, IgM & complement
Explanation:In type II hypersensitivity the antibodies, IgG and IgM bind to antigens to form complexes that activate the classical pathway of complement to eliminate cells presenting foreign antigens.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 21
Incorrect
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A 70-year-old male presents with chest pain. His past medical history includes hypertension and angina. He continues to smoke about 20 cigarettes per day despite being advised about lifestyle modifications.Blood investigations obtained in the emergency department show:Na+: 133 mmol/lK+: 3.3 mmol/lUrea: 4.5 mmol/lCreatinine: 90 μmol/lWhich among the following is the most likely explanation for the abnormalities seen in the above investigations?
Your Answer: Spironolactone therapy
Correct Answer: Bendroflumethiazide therapy
Explanation:The blood investigations in this patient reveal hyponatremia as well as hypokalaemia. Among the options provided, Bendroflumethiazide therapy can cause the above presentation with the electrolyte disturbances. Note:- Spironolactone is a potassium-sparing diuretic that is associated with hyperkalaemia.- Enalapril therapy can cause side effects of dizziness, hypotension, cough, and rarely a rash.- Felodipine therapy can cause side effects of dizziness, headache, cough, and palpitations.
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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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Tunica intima is made up of?
Your Answer: Endothelial cells
Explanation:Tunica intima is a single cell thick lining of endothelial cells that lines the inside of the blood vessels. It is the inner most layer of the blood vessel.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 23
Correct
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The predominant site in the lymph node where T lymphocytes are found is:
Your 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 24
Correct
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In a study, 50 out of 100 smokers developed lung cancers and 50 out of 200 non-smokers developed lung cancers. Which of the following is accurate?
Your Answer: Relative risk=2
Explanation:Relative risk = (Incidence in exposed group)/incidence in unexposed group). So in this case RR = (50/100)/(50/200) = 2.
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This question is part of the following fields:
- Medicine
- Research Skills
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Question 25
Incorrect
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Choose the correct answer: fibers in the superior cerebellar peduncle:
Your Answer: Are mainly lateral spinothalamic tracts
Correct Answer: Are mainly ventral spinocerebellar tracts from the cerebellar nuclei to the thalamus and red nucleus
Explanation:There are three cerebellar peduncles with different connections and functions. The three are mainly, superior, middle and inferior. The superior cerebellar peduncle is also known as the “Brachium conjunctivum”. It predominantly contains efferent fibers from the cerebellar nuclei, as well as some afferents from the spinocerebellar tract. The efferent pathways include cerebellorubral, dentatothalamic, and fastigioreticular fibers. These are tracts projecting from the deep cerebellar nuclei to the thalamus and red nucleus. The middle cerebellar peduncle connects to the pontine nucleus and the dorsal spinocerebellar tracts run through the superior cerebellar peduncle.
The superior cerebellar peduncle contains vital afferent and efferent fibers including cerebellothalamic, cerebellorubral and ventrospinocerebellar tracts.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 26
Incorrect
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In which organ will you find extremely porous sinusoidal capillaries, with discontinuous endothelium?
Your Answer: Kidneys
Correct Answer: Liver
Explanation:The liver is the organ which contains sinusoidal capillaries with discontinuous endothelium. The brain, lungs and the intestine all contain continuous capillaries, however the kidney contains fenestrated capillaries to aid in filtration.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 27
Incorrect
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Which hormone secreting cell of the human anterior pituitary gland secretes growth hormone?
Your Answer: Gonadotroph
Correct Answer: Somatotroph
Explanation:Somatotroph cells are responsible for the production of growth hormone. Somatotrophs occupy nearly 40% of the total surface area of the anterior pituitary, and they are acidophilic in nature.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 28
Correct
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The infoldings or spaces between the bases of the villi are known as
Your Answer: Crypts of Lieberkühn
Explanation:An intestinal gland (also crypt of Lieberkühn and intestinal crypt) is a gland found in the intestinal epithelium lining of the small intestine and large intestine (colon) between the villi.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 29
Incorrect
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What is the function of Activated protein C?
Your Answer: Activates factor V
Correct Answer: Inactivates factor Va
Explanation:Activated Protein C (APC) is a crucial protein in the regulation of blood coagulation. Its primary functions include:
- Inactivating Factor Va: APC inactivates Factor Va, which is a cofactor for the conversion of prothrombin to thrombin by Factor Xa. By inactivating Factor Va, APC reduces thrombin formation, thereby acting as an anticoagulant.
- Inactivating Factor VIIIa: APC also inactivates Factor VIIIa, another cofactor that assists Factor IXa in the conversion of Factor X to Factor Xa. This further contributes to its anticoagulant effect.
These actions help to regulate blood clotting and prevent excessive thrombosis.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 30
Incorrect
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Which of the following corresponds to an oblique line drawn from the sternal end of the left 3rd costal cartilage to the sternal end of the right 6th costal cartilage?
Your Answer: Aortic arch
Correct Answer: Atrio-ventricular (coronary) groove
Explanation:The AV groove corresponds to the right border of the heart. The right border corresponds to a line drawn from the 3rd right costal cartilage to the 6th right costal cartilage; this border is slightly convex to the right.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 31
Incorrect
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A 45 year old man presents with fever, malaise, weight loss and myalgias that have been occurring for a month. You suspect polyarteritis nodosa and arrange for some lab investigations. Which of the following abnormality would most likely be present?
Your Answer: Positive ANCA
Correct Answer: Elevated creatinine
Explanation:People with polyarteritis nodosa often exhibit anaemia of chronic disease. Leucocytosis and eosinophilia may also be present. ANCA is only rarely positive. As polyarteritis nodosa affects the kidneys as well, the creatinine is elevated in most cases.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 32
Correct
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The conversion of fructose to fructose 1-phosphate is catalysed by:
Your Answer: Fructokinase
Explanation:The first step in the metabolism of fructose is the phosphorylation of fructose to fructose 1-phosphate by fructokinase.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 33
Incorrect
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Cranial nerves VI, VII, VIII enter/exit the base of the brain at the:
Your Answer: Pons
Correct Answer: Ponto-medullary junction
Explanation:Cranial nerves III, IV and V exit from the pons, VI, VII, VIII exit from the pontomedullary junction and cranial nerve IX, X, XI, XII exit from the medulla.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 34
Incorrect
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The following products of the vascular endothelium produce vasodilation except:
Your Answer: Vascular endothelial growth factor
Correct Answer: Endothelin
Explanation:Endothelin: This is incorrect in the context of vasodilation. Endothelin is actually a potent vasoconstrictor produced by the endothelium, leading to the narrowing of blood vessels and increased blood pressure.
Nitrous oxide (Nitric oxide): This is correct for vasodilation. Nitric oxide is a powerful vasodilator produced by the endothelium, which helps relax and widen blood vessels.
Prostacyclin: This is correct for vasodilation. Prostacyclin (PGI2) is a vasodilator and inhibits platelet aggregation, helping to maintain blood flow and reduce clot formation.
Endothelial-derived hyperpolarizing factor (EDHF): This is correct for vasodilation. EDHF causes vasodilation by hyperpolarizing the smooth muscle cells of blood vessels.
Vascular endothelial growth factor (VEGF): This is correct for vasodilation. VEGF primarily promotes the growth of new blood vessels but also has vasodilatory effects through nitric oxide production.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 35
Correct
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Question 36
Incorrect
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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 37
Correct
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Question 38
Incorrect
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Where is retinol mainly stored?
Your Answer: Terminal ileum
Correct Answer: Liver
Explanation:Vitamin A is a group of unsaturated nutritional organic compounds that includes retinol, retinal, retinoic acid, and several provitamin A carotenoids (most notably beta-carotene). The liver stores a multitude of substances, including glucose (in the form of glycogen), vitamin A (1–2 years’ supply), vitamin D (1–4 months’ supply), vitamin B12 (3–5 years’ supply), vitamin K, iron, and copper.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 39
Correct
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There is a measure of dispersion of a set of data from its mean. Which of following is the best term which can describe the above?
Your Answer: Standard deviation (root mean square deviation)
Explanation:Standard deviation is defined as the measure of dispersion of a set of data from its mean. It measures the absolute variability of a distribution; the higher the dispersion or variability, the greater is the standard deviation and greater will be the magnitude of the deviation of the value from their mean.
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This question is part of the following fields:
- Medicine
- Research Skills
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Question 40
Correct
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The process by which DNA fragments are separated by gel and transferred onto a membrane sheet is called:
Your Answer: Southern blotting
Explanation:A Southern blot is a method used in molecular biology for detection of a specific DNA sequence in DNA samples. Southern blotting combines transfer of electrophoresis-separated DNA fragments to a filter membrane and subsequent fragment detection by probe hybridization. The other forms of blotting involve the use of RNA and proteins.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 41
Incorrect
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Where are the baroreceptors of the great arteries located?
Your Answer: In the endothelium
Correct Answer: In the adventitia
Explanation:Arterial baroreceptors are located in the aortic arch and carotid sinuses, and are formed by small nerve endings present in the adventitia of these vessels.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 42
Incorrect
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A 45 year old man, known case of hypothyroidism, presents with a 3 month history of pain and stiffness in the joints of his hands and feet. He also complains of dyspnoea occurring for the past 6 weeks. On examination there is a right pleural effusion and swollen hand joints. The clinician makes a diagnosis of rheumatoid arthritis. Which of the following is most characteristic of a rheumatoid pleural effusion?
Your Answer: It has a high pH
Correct Answer: It has a low glucose level
Explanation:The typical “rheumatoid effusion” is a sterile exudative fluid with low pH (<7.3), low glucose (700 IU). It should initially be treated with NSAIDs. Decortication should be reserved in patients with thickened pleura who have symptomatic dyspnoea.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 43
Incorrect
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90% of erythropoietin necessary for haemopoesis is produced by the kidneys, the remainder is formed in the?
Your Answer: Spleen
Correct Answer: Liver
Explanation:Erythropoietin is produced by interstitial fibroblasts in the kidney in close association with peritubular capillary and proximal convoluted tubule. It is also produced in perisinusoidal cells in the liver. While liver production predominates in the fetal and perinatal period, renal production is predominant during adulthood.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 44
Correct
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Major supplies of glycogen are found in ….
Your Answer: Liver and skeletal muscle
Explanation:The two major sites of glycogen storage are the liver and skeletal muscle. The concentration of glycogen is higher in the liver than in muscle however more glycogen is stored in skeletal muscle due to its greater mass.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 45
Incorrect
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The mechanism of action of low molecular weight heparin, has the greatest effect on which of the following components of the coagulation cascade?
Your Answer: Thrombin
Correct Answer: Factor Xa
Explanation:Mechanism of action of low molecular weight heparin (LMWH): It inhibits coagulation by activating antithrombin III. Antithrombin III binds to and inhibits factor Xa. In doing so it prevents activation of the final common path; Xa inactivation means that prothrombin is not activated to thrombin, thereby not converting fibrinogen into fibrin for the formation of a clot. LMHW is a small fragment of a larger mucopolysaccharide, heparin. Heparin works similarly, by binding antithrombin III and activating it. Heparin also has a binding site for thrombin, so thrombin can interact with antithrombin III and heparin, thus inhibiting coagulation. Heparin has a faster onset of anticoagulant action as it will inhibit not only Xa but also thrombin, while LMWH acts only on Xa inhibition.Compared to heparin, LMWHs have a longer half-life, so dosing is more predictable and can be less frequent, most commonly once per day.Dosage and uses:LMWH is administered via subcutaneous injection. This has long-term implications on the choice of anticoagulant for prophylaxis, for example, in orthopaedic patients recovering from joint replacement surgery, or in the treatment of DVT/PE.Adverse effects:The main risk of LMWH will be bleeding. The specific antidote for heparin-induced bleeding is protamine sulphate.Less commonly it can cause:Heparin-induced thrombocytopenia (HIT)Osteoporosis and spontaneous fracturesHypoaldosteronismHypersensitivity reactions
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 46
Correct
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A 28 year old male arrives at the clinic complaining of fever, arthralgia and urethritis. On examination, the ankle is swollen and there is a pustular rash on the dorsal foot. What is the most likely diagnosis?
Your Answer: Disseminated gonorrhoea
Explanation:DGI presents as two syndromes: 1) a bacteremic form that includes a triad of tenosynovitis, dermatitis, and polyarthralgias without purulent arthritis and 2) a septic arthritis form characterized as a purulent arthritis without associated skin lesions. Many patients will have overlapping features of both syndromes. Time from infection to clinical manifestations may range from 1 day to 3 months. There is no travel history and the rash of Lyme disease is not purulent. Reactive arthritis presents with conjunctivitis, urethritis and arthritis usually with a red hot tender and swollen joint.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 47
Incorrect
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The pontine tegmentum as part of the midbrain, contains which cranial nerve nuclei?
Your Answer: CN 1 to 2
Correct Answer: CN 5 to 8
Explanation:The pontine tegmentum also known as dorsal pons is located within the brain stem. Several cranial nerve nuclei are located in the pontine tegmentum. The nuclei of CN V, CN VI, CN VII and CNVIII are located in the pontine tegmentum.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 48
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 49
Incorrect
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Which of the following is the smallest cell of the nervous system?
Your Answer: Astrocyte
Correct Answer: Microglia
Explanation:Microglia are the smallest of the neuroglial cells in the nervous system. They are scattered throughout the central nervous system and have phagocytic properties.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 50
Incorrect
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Sympathetic supply to the stomach is derived from
Your Answer: T8-T12 spinal segments via the superior mesenteric ganglion
Correct Answer: T5-T9 spinal segments via the coeliac ganglion
Explanation:Parasympathetic innervation to the stomach is from the vagus nerve and the sympathetic innervation is from the T5-T9 spinal segments via the coeliac ganglion through the greater splanchnic nerve.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 51
Correct
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Which of the following tracts are involved in the control of vital functions?
Your Answer: Reticulospinal
Explanation:Reticulospinal tract pass down from the reticular formation of the mid brain, pons and medulla. It descends in the lateral white column. Both sets of fibers enter the anterior grey column and may facilitate or inhibit the gamma and alpha neurons. By this means the reticulospinal tract controls voluntary and reflex activities. It also contains the descending autonomic fiber, thus providing a pathway for the hypothalamus to control the sympathetic and parasympathetic pathways.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 52
Incorrect
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A 72 year old retired fisherman presents with weakness of shoulders and hips over the last four months. Finger flexion is also weak but the extension is normal. There has been some difficulty swallowing liquids. Past medical history is not significant except for sexually transmitted disease that he caught some 40 years ago in South Pacific and got treated with antibiotics. He smokes and drinks one or two tots of rum at the weekend. Creatine kinase level is 125. Which of the following investigations is most significant in establishing a diagnosis?
Your Answer: 24 hour urine collection for myoglobin
Correct Answer: Muscle biopsy with electron microscopy
Explanation:Inclusion body myositis (IBM) is a progressive muscle disorder characterized by muscle inflammation, weakness, and atrophy (wasting). It is a type of inflammatory myopathy. IBM develops in adulthood, usually after age 50. The symptoms and rate of progression vary from person to person. The most common symptoms include progressive weakness of the legs, arms, fingers, and wrists. Some people also have weakness of the facial muscles (especially muscles controlling eye closure), or difficulty swallowing (dysphagia). Muscle cramping and pain are uncommon, but have been reported in some people. The underlying cause of IBM is poorly understood and likely involves the interaction of genetic, immune-related, and environmental factors. Some people may have a genetic predisposition to developing IBM, but the condition itself typically is not inherited. Elevated creatine kinase (CK) levels in the blood (at most ,10 times normal) are typical in IBM. Muscle biopsy may display several common findings including; inflammatory cells invading muscle cells, vacuolar degeneration, inclusions or plaques of abnormal proteins.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 53
Incorrect
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Which of the following is the most common clinical feature of carbon monoxide poisoning?
Your Answer: Confusion
Correct Answer: Headache
Explanation:Carbon monoxide (CO) poisoning:It is considered as the great imitator of other diseases as the patients present with a myriad of symptoms. The carbon monoxide diffuses rapidly across the pulmonary capillary membrane binding to the haem molecule with a very high affinity (240 times that of oxygen) forming carboxy-haemoglobin (COHb). Non-smokers have a baseline COHb of ,3% while smokers have a baseline COHb of 10-15%.Clinical features of carbon monoxide toxicity:Headache: 90% of cases (most common clinical feature)Nausea and vomiting: 50%Vertigo: 50%Confusion: 30%Subjective weakness: 20%Severe toxicity: ‘pink’ skin and mucosa, hyperpyrexia, arrhythmias, extrapyramidal features, coma, deathCherry red skin is a sign of severe toxicity and is usually a post-mortem finding.Management• 100% oxygen• Hyperbaric oxygen therapy (HBOT)The use of Hyperbaric oxygen therapy (HBOT) for treatment mild to moderate CO poisoning is not routine.The selection criteria for HBOT in cases of CO poisoning include:• COHb levels > 20-25%• COHb levels > 20% in pregnant patient • Loss of consciousness• Severe metabolic acidosis (pH <7.1)• Evidence of end-organ ischemia (e.g., ECG changes, chest pain, or altered mental status)
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 54
Correct
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Question 55
Incorrect
-
A study is carried out to assess the efficacy of a rapid urine screening test developed to detect Chlamydia. The total number of people involved in the study were 200. The study compared the new test to the already existing NAAT techniques. The new test was positive in 20 patients that were Chlamydia positive and in 3 patients that were Chlamydia negative. For 5 patients that were Chlamydia positive and 172 patients that were Chlamydia negative the test turned out to be negative. Choose the correct value regarding the negative predictive value of the new test:
Your Answer: 172/192
Correct Answer: 172/177
Explanation:The definition of negative predictive value is the probability that the individuals with truly negative screening test don’t have Chlamydia. The equation is the following: Negative predictive value = Truly negative/(truly negative + false negative) = 172 / (172 + 5) = 172 / 177
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This question is part of the following fields:
- Medicine
- Research Skills
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Question 56
Incorrect
-
In the clotting mechanism, activation of factor IX can occur through the direct actions of:
Your Answer: Thrombin & factor VIa
Correct Answer: Factor VIIa & XIa
Explanation:Factor IX is processed to remove the signal peptide, glycosylated and then cleaved by factor XIa (of the contact pathway) or factor VIIa (of the tissue factor pathway). When activated into factor IXa, in the presence of Ca2+, membrane phospholipids, and a Factor VIII cofactor, it hydrolyses one arginine-isoleucine bond in factor X to form factor Xa. Factor IX is inhibited by antithrombin.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 57
Correct
-
Which coronary artery supplies the right atria?
Your Answer: Right coronary
Explanation:The left coronary artery distributes blood to the left side of the heart, the left atrium and ventricle, and the interventricular septum. The circumflex artery arises from the left coronary artery and follows the coronary sulcus to the left. Eventually, it will fuse with the small branches of the right coronary artery. The right coronary artery proceeds along the coronary sulcus and distributes blood to the right atrium, portions of both ventricles, and the heart conduction system.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 58
Incorrect
-
The chromosomes that principally encode for proteins or RNA molecules involved in mitochondrial function are found:
Your Answer: In the rough endoplasmic reticulum
Correct Answer: In the nucleus of each diploid cell
Explanation:While mitochondria have their own small circular DNA (mtDNA) that encodes some of the proteins and RNAs required for mitochondrial function, the majority of proteins involved in mitochondrial function are encoded by nuclear DNA. These nuclear genes are transcribed in the nucleus and then translated into proteins in the cytoplasm. The proteins are subsequently imported into the mitochondria.
Therefore, the correct answer is:
- In the nucleus of each diploid cell
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This question is part of the following fields:
- Genetics
- Medicine
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Question 59
Incorrect
-
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: Ventricular septal defect
Correct 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 60
Correct
-
Microtubule disassembly:
Your Answer: Occurs at the positive and negative end
Explanation:Dynamic instability refers to the coexistence of assembly and disassembly at the ends of a microtubule. The microtubule can dynamically switch between growing and shrinking phases in this region. Although both assembly and disassembly occur at both ends they occur preferentially at the (+) end.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 61
Incorrect
-
An 81 year old male patient was admitted after an ischaemic stroke. Physical examination reveals left hemiparesis. How would you classify this hemiparesis based on the WHO International Classification of Functioning, Disability and Health?
Your Answer: Activity limitation
Correct Answer: Impairment of body function
Explanation:Symptoms and signs are classified as ‘impairment of body function’. The types of impairment classified as ‘activity limitation’ include difficulties that a patient may have in executing certain activities. The type of impairment classified as ‘participation restriction’ are problems a patient may have in social roles. The type of impairment classified as ‘pathology’ would be the diagnosis/disease. Right total anterior circulation infarct relates to the Oxford Bamford classification for stroke.
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This question is part of the following fields:
- Geriatrics
- Medicine
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Question 62
Correct
-
Which of the following is a granulocyte?
Your Answer: Eosinophil
Explanation:Granulocytes are a category of white blood cells characterized by the presence of granules in their cytoplasm. There are three principal types of granulocytes, distinguished by their appearance under Wright’s stain:
- Basophil granulocytes
- Eosinophil granulocytes
- Neutrophil granulocytes
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This question is part of the following fields:
- Haematology
- Medicine
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Question 63
Incorrect
-
Concerning coronary arteries, what is the net effect of B2 stimulation on the heart (e.g. Running athlete)?
Your Answer: No change in coronary artery diameter
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
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Question 64
Correct
-
A 56-year-old male presents to the emergency department with confusion and agitation for the past four hours. He is a known alcoholic who has abstained from drinking for the past three days.On examination, he is sweating, agitated and disorientated. His temperature is 37.7°C, pulse 112 bpm regular and blood pressure is 150/76 mmHg. Blood investigations performed in the emergency department reveal:FBC: NormalU&E: NormalPlasma glucose: 4.6 mmol/l (3.6-6)Which of the following medications would be the most appropriate treatment for this man?
Your Answer: Oral lorazepam
Explanation:The most probable diagnosis for this patient is delirium tremens due to alcohol withdrawal, which should be treated as a medical emergency. Delirium tremens is a hyperadrenergic state and is often associated with tachycardia, hyperthermia, hypertension, tachypnoea, tremor, and mydriasis.Treatment:- The most common and validated treatment for alcohol withdrawal is benzodiazepine: first-line treatment includes oral lorazepam. – If the symptoms persist, or the medication is refused, parenteral lorazepam, haloperidol or olanzapine should be given.- Central-acting, alpha-2 agonists such as clonidine and dexmedetomidine should not be used alone for the treatment of alcohol withdrawal.- It is also recommended to avoid using alcohol, antipsychotics, anticonvulsants, beta-adrenergic receptor blockers, and baclofen for the treatment of alcohol withdrawal as there are not enough studies to support the safety of these.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 65
Correct
-
A 30-year-old female presents with a 4-day history of diarrhoea and vomiting. She has been unable to keep fluids down for 4 days and has been treated with metoclopramide. She develops a dystonic reaction. What is the most appropriate treatment for this woman?
Your Answer: Benztropine
Explanation:Acute dystonic reactions (extrapyramidal symptoms) such as spasmodic torticollis, trismus, and oculogyric crises can occur following the administration of metoclopramide or stemetil and thus, neither is recommended for the treatment of nausea in young women.
Such reactions respond well to treatment with benztropine or procyclidine.
– Benztropine: It is an anticholinergic medication with significant CNS penetration. A single dose of benztropine 1 to 2 mg IV followed by 1 to 2 mg p.o twice a day for up to 7 days to prevent a recurrence. Subsequently, both the offending agent and those from the same group should be avoided.
– Alternatively, diphenhydramine can be used intravenously (up to a dose of 50mg) or intramuscularly followed by p.o therapy every 6 hours for 1 to 2 to prevent a recurrence.- Second-line therapy with IV benzodiazepines is reserved for those patients who do not respond to anticholinergics.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 66
Correct
-
Which hormone results in the production of pancreatic juice rich in enzymes but low in volume?
Your Answer: Cholecystokinin
Explanation:Cholecystokinin (CCK) mediates digestion in the small intestine by inhibiting gastric emptying and decreasing gastric acid secretion. It stimulates the acinar cells of the pancreas to release a juice rich in pancreatic digestive enzymes, hence the old name pancreozymin.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 67
Correct
-
How does the proximal convoluted tubule excrete H+?
Your Answer: Via Na+/H+ antiporter.
Explanation:H+ secretion from cells across the luminal membrane is mostly in exchange for Na+ ions, and to a small extent, through a proton ATPase. Secreted H+ react with filtered HC03- to form H2CO3.
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This question is part of the following fields:
- Medicine
- Renal
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Question 68
Incorrect
-
Which of the following statements are true regarding human herpesvirus eight
Your Answer: It may the associated with myeloproliferative disorders.
Correct Answer: It is sexually transmitted.
Explanation:Kaposi’s sarcoma-associated herpesvirus (KSHV) is the eighth human herpesvirus or HHV-8. This virus causes Kaposi’s sarcoma, a cancer commonly occurring in AIDS patients, as well as primary effusion lymphoma and some types of multicentric Castleman’s disease. It is one of seven currently known human cancer viruses, or oncoviruses. The mechanisms by which the virus is contracted are not well understood. Healthy individuals can be infected with the virus and show no signs or symptoms, due to the immune system’s ability to keep the infection in check. Infection is of particular concern to the immunosuppressed. Cancer patients receiving chemotherapy, AIDS patients and organ transplant patients are all at a high risk of showing signs of infection. The virus is sexually transmitted.
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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Question 69
Incorrect
-
A 56 year old obese female presents due to moderate pain in her finger joints which occurs mostly at the end of the day which gets better with rest. There is also some associated swelling. On examination, there is enlargement of her distal interphalangeal joints and tenderness to palpation. Which of the following is the most likely diagnosis?
Your Answer: Gout
Correct Answer: Osteoarthritis
Explanation:Osteoarthritis (OA) is a disabling joint disease characterized by a noninflammatory degeneration of the joint complex (articular cartilage, subchondral bone, and synovium) that occurs with old age or from overuse. It mainly affects the weight-bearing and high-use joints, such as the hip, knee, hands, and vertebrae. Despite the widespread view that OA is a condition caused exclusively by degenerative “wear and tear” of the joints, newer research indicates a significant heterogeneity of causation, including pre-existing peculiarities of joint anatomy, genetics, local inflammation, mechanical forces, and biochemical processes that are affected by proinflammatory mediators and proteases. Major risk factors include advanced age, obesity, previous injuries, and asymmetrically stressed joints. In early-stage osteoarthritis, patients may complain of reduced range of motion, joint-stiffness, and pain that is aggravated with heavy use. As the disease advances, nagging pain may also occur during the night or at rest. Diagnosis is predominantly based on clinical and radiological findings. Classic radiographic features of OA do not necessarily correlate with clinical symptoms and appearance. RA involves proximal interphalangeal joints not distal. Gout occurs as a result of overproduction or underexcretion of uric acid and frequently involves first toe. Fibromyalgia is a disorder characterized by widespread musculoskeletal pain accompanied by fatigue, sleep, memory and mood issues.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 70
Incorrect
-
B1 adrenergic stimulation produces:
Your Answer: Negative inotropy
Correct Answer: Increase in calcium cytosolic concentration
Explanation:Norepinephrine secreted by the sympathetic endings binds to B1 receptors, and the resulting increase in intracellular cAMP facilitates the opening of L channels, increasing Ica and the rapidity of the depolarization phase of the impulse and activates PKA which leads to phosphorylation of the voltage-gated Ca2+ channels, causing them to spend more time in the open state.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 71
Correct
-
A 48-year-old male with a history of bipolar disorder presents with acute confusion. In-transit to hospital he had a generalized seizure which terminated spontaneously after around 30 seconds. On arrival to the emergency department, his GCS is 14/15 and he is noted to have a coarse tremor. Suspecting a diagnosis of lithium toxicity, intravenous access is obtained, a blood sample was drawn for investigations and a saline infusion is started. The blood investigations revealed:Lithium level: 4.2 mmol/lNa+: 136 mmol/lK+: 4.6 mmol/lUrea: 8.1 mmol/lCreatinine: 99 µmol/lBicarbonate: 18 mmol/lWhat is the most appropriate management for the patient?
Your Answer: Arrange haemodialysis
Explanation:The presentation of the patient is typical of chronic lithium toxicity (due to the presence of mainly neurological manifestations). Additional to the blood investigations mentioned, urine analysis, electrolyte levels, and renal function should also be performed. A low urine Anion gap and a low urine specific gravity are highly suggestive of lithium toxicity.ECG obtained in this patient is likely to show: nonspecific, diffuse ST segment depression with T wave inversion.Acute lithium toxicity presents with more GI manifestations while, the clinical features of chronic lithium toxicity are mainly neurological and can include:Coarse tremors (fine tremors are seen in therapeutic levels), hyperreflexia, acute confusion, seizures, and coma.The management of lithium toxicity is as follows:Immediate GI decontamination with gastric lavage (in case of acute intoxication)Saline Administrations: the goal of saline administration is to restore GFR, normalize urine output and enhance lithium clearance.Haemodialysis remains the mainstay treatment for lithium toxicity as lithium is readily dialyzed because of water solubility, low volume of distribution, and lack of protein binding.The Extracorporeal Treatments in Poisoning Workgroup (EXTRIP Workgroup) recommendations for dialysis (extracorporeal treatment) in lithium toxicity include:• Impaired kidney function and lithium levels > 4.0 mEq/L• Decreased consciousness, seizures, or life-threatening dysrhythmias, regardless of lithium levels• Levels are > 5.0 mEq/L, significant confusion is noted, or the expected time to reduce levels to < 1.0 mEq/L is more than 36 hoursAs post-dialysis rebound elevations in lithium levels have been documented, continuous veno-venous hemofiltration (CVVH) has been advocated.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 72
Correct
-
What is the function of secondary messengers?
Your Answer: Communication from extracellular to intracellular signalling pathways
Explanation:First messengers may not physically cross the phospholipid bilayer to initiate changes within the cell directly. This functional limitation necessitates the cell to devise signal transduction mechanisms to transduce first messenger into second messengers, so that the extracellular signal may be propagated intracellularly. Second messengers are intracellular signalling molecules released by the cell to trigger physiological changes such as proliferation, differentiation, migration, survival, and apoptosis. Secondary messengers are therefore one of the initiating components of intracellular signal transduction cascades.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 73
Incorrect
-
Carcinogens found in cigarette smoke can transform proto-oncogenes to oncogenes through:
Your Answer: Mutations in p53
Correct Answer: Point mutations in genomic DNA
Explanation:80% of the pancreatic cancers are environmentally influenced by smoking which increases the risk by 50%. Mutation can occur in the KRAS, p16, SMAD4, and TP53 genes among other tumour suppression genes. Smoking can be implicated in transformation of all these genes. Apart from KRAS all the genes are inactivated in pancreatic cancer. As KRAS is the most commonly altered gene, mutation occurs as point mutation. As smoking is the most common aetiology in pancreatic cancer, and KRAS is the most important gene that is altered. Most commonly cigarette smoke causes point mutation.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 74
Incorrect
-
Which cell secretes parathyroid hormone?
Your Answer: Parafollicular cells
Correct Answer: Chief cells
Explanation:Parathyroid chief cells, also known as parathyroid principal cells or parathyroid cells, are the most prevalent type of cell in the parathyroid gland and the only ones present at birth. They secrete parathyroid hormone (PTH).
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 75
Incorrect
-
Transport of Ca2+ into the reticulum to initiate cardiac muscle relaxation in via:
Your Answer: Voltage-gated Ca2+ channels
Correct Answer: Serca (sarcoplasmic or endoplasmic reticulum Ca2+ ATPase)
Explanation:Phosphorylation of phospholamban, which increases calcium ATPase activity and sequestration of calcium in the sarcoplasmic reticulum. An increased rate of relaxation is explained because cAMP also activates the protein phospholamban, situated on the membrane of the SR, that controls the rate of uptake of calcium into the SR. The latter effect explains enhanced relaxation (lusitropic effect).
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 76
Correct
-
Psoriatic arthropathy most commonly presents with which of the following types of arthritis?
Your Answer: Peripheral asymmetric oligoarthropathy
Explanation:Most patients with psoriatic arthritis present with monoarthritis or asymmetric oligoarthritis. The most common form of the disease is the one involving a few joints of the peripheral skeleton with a distinct asymmetry of symptoms. Involvement of the smaller joints of the hands and feet, especially distal interphalangeal joints, seems to be a characteristic feature. Arthritis mutilans is a rare and severe complication of psoriatic arthritis.
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This question is part of the following fields:
- Connective Tissue
- Medicine
-
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Question 77
Incorrect
-
In paralytic ileus the following are true except:
Your Answer: There is a reflex inhibition due to increased discharge of noradrenergic fibers
Correct Answer: Opioid blocking drugs will exacerbate the symptoms
Explanation:Paralytic ileus causes adynamic intestinal obstruction or decreased peristalsis and the most common reason being postoperative ileus. Opioid drugs like morphine are given for pain management and cause decreased peristalsis in the gut resulting in constipation. Theoretically opioid blocking drugs or opioid antagonists can increase peristalsis and can alleviate paralytic ileus symptoms.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 78
Correct
-
What is the protective hexametric sequence at the ends of chromosomes called?
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 79
Incorrect
-
Where on the surface of the chest is the normal site of auscultation for the mitral area?
Your Answer: 5th left intercostal space mid-axillary line
Correct Answer: 4th left intercostal space in the mid-clavicular line
Explanation:The mitral valve is situated in the left 4th intercostal space just beneath the sternum, in the mid clavicular line.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 80
Correct
-
In the Fick‘s method of measuring cardiac output, the arterial oxygen content can be measured in a sample obtained from
Your Answer: The pulmonary vein
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.Note 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 81
Correct
-
Gastrin activates all of the following cells except:
Your Answer: Mucus neck cells
Explanation:The G cell is a type of cell in the stomach and duodenum that secretes gastrin. It works in conjunction with gastric chief cells and parietal cells. G cells are found deep within the pyloric glands of the stomach antrum, and occasionally in the pancreas and duodenum. Gastrin-releasing peptide, as well as the presence of amino acids in the stomach, stimulates the release of gastrin from the G cells. Gastrin stimulates enterochromaffin-like cells to secrete histamine. Gastrin also targets parietal cells by increasing the amount of histamine and the direct stimulation by gastrin, causing the parietal cells to increase HCl secretion in the stomach.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 82
Correct
-
During bone growth-the epiphysis are separated from the diaphysis by actively proliferating cartilage known as:
Your Answer: Epiphysial plate
Explanation:The epiphysial plate, physis, or growth plate, is a hyaline cartilage plate located near the ends of long bones; it consists of growing tissue. It is found in children and teenagers; in adults, it is replaced by an epiphysial line or epiphysial closure. The epiphysial plate is divided into zones: zone of reserve, proliferation, maturation and hypertrophy, calcification, and ossification.
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This question is part of the following fields:
- Endocrinology
- Medicine
-
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Question 83
Incorrect
-
The functional unit of the liver is called?
Your Answer: Hepatocyte
Correct Answer: Acini
Explanation:From a metabolic perspective, the functional unit is the hepatic acinus (terminal acinus), each of which is centred on the line connecting two portal triads and extends outwards to the two adjacent central veins. The periportal zone I is nearest to the entering vascular supply and receives the most oxygenated blood, making it least sensitive to ischemic injury while making it very susceptible to viral hepatitis. Conversely, the centrilobular zone III has the poorest oxygenation, and will be most affected during a time of ischemia.
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This question is part of the following fields:
- Hepatobiliary
- Medicine
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Question 84
Correct
-
What is the most important determinant of ECF volume?
Your Answer: The amount of sodium in the ECF
Explanation:The volume of the ECF is determined primarily by the total amount of osmotically active solute in the ECF. The composition of the ECF is discussed in Chapter 1. Because Na+ and Cl− are by far the most abundant osmotically active solutes in ECF, and because changes in Cl− are to a great extent secondary to changes in Na+, the amount of Na+ in the ECF is the most important determinant of ECF volume.
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This question is part of the following fields:
- Medicine
- Renal
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Question 85
Incorrect
-
The pathway responsible for the discriminative aspect of pain, is called the:
Your Answer: Spinothalamic tractus
Correct Answer: Neospinothalamic tract
Explanation:The spinothalamic tract is an ascending or a sensory tract, responsible for transmission of pain and temperature. The neospinothalamic tract is responsible for fast pain or discriminative pain whereas the palaeospinothalamic tract is responsible for transmission of slow pain.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 86
Incorrect
-
Translation usually begins at which codon?
Your Answer: UAA
Correct Answer: AUG
Explanation:The start codon is the first codon of a messenger RNA (mRNA) transcript translated by a ribosome. The start codon always codes for methionine in eukaryotes and the most common start codon is AUG.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 87
Incorrect
-
In the gastric mucosa, which of the following cells is known to secrete gastric lipase?
Your Answer: Parietal cell
Correct Answer: Chief cell
Explanation:Chief cells produce pepsinogen and gastric lipase. Parietal cells produce stomach acid and intrinsic factor.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 88
Incorrect
-
The length of DNA is generally measured in terms of 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 89
Incorrect
-
A 20-year-old female has been admitted with an acute infection. She gives a history suggestive of hypersensitivity to amoxicillin. After consultation with the allergy specialist, she has now been diagnosed with an IgE mediated penicillin allergy. Which of the following drugs should be avoided in this patient?
Your Answer: Ciprofloxacin
Correct Answer: Cefalexin
Explanation:Cefalexin should be avoided in this patient.This patient is known to have a severe penicillin allergy. None of the above antibiotics are penicillin based. However, 0.5 – 6.5% of patients who are proven to have an IgE mediated penicillin allergy will also be allergic to cephalosporins, including cefalexin. Penicillin, cephalosporins, and carbapenems are all members of the beta-lactam group of antibiotics and share a common beta-lactam ring. There is, therefore, a small risk of allergy cross-over between all these antibiotics. The rates of allergy cross-over are lower with second and third-generation cephalosporins than first-generation cephalosporins such as cefalexin.It is important to question the patient carefully to ascertain what symptoms they had on exposure to penicillin. Symptoms such as an urticarial rash or itching make it more likely that they have an IgE mediated allergy.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 90
Incorrect
-
Which of the following statements regarding influenza virus is correct?
Your Answer: Minor changes in Influenza A and B viruses via point mutations is called antigenic shift
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
-
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Question 91
Incorrect
-
Stem cell characteristics include the following except
Your Answer: Ability to proliferate / differentiate outside the bone marrow in an adult during times of stress/disease of the bone marrow
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
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This question is part of the following fields:
- Haematology
- Medicine
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Question 92
Correct
-
What is the most abundant cell type in the central nervous system called?
Your Answer: Astrocyte
Explanation:Astrocytes are the supporting cells of the central nervous system. There are two types; the fibrous type is found in the white matter and the protoplasmic type in the grey matter. They are the most abundant cell type in the CNS.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 93
Correct
-
Tumour necrosis factor is a cytokine. What is its major function?
Your Answer: Promotion of inflammation
Explanation:Tumour necrosis factor (TNF) is a cytokine that has a wide variety of functions. It can cause cytolysis of certain tumour cell lines; it is involved in the induction of cachexia; it is a potent pyrogen, causing fever by direct action or by stimulation of interleukin-1 secretion; it can stimulate cell proliferation and induce cell differentiation under certain conditions.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 94
Correct
-
The extrinsic coagulation pathway is initiated by activation of which clotting factor?
Your Answer: Factor VII
Explanation:The tissue factor pathway (extrinsic) begins following damage to the blood vessel. FVII leaves the circulation and comes into contact with tissue factor (TF) expressed on tissue-factor-bearing cells (stromal fibroblasts and leukocytes), forming an activated complex (TF-FVIIa).
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This question is part of the following fields:
- Haematology
- Medicine
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Question 95
Correct
-
The brainstem contains which of the following structures?
Your Answer: The midbrain, pons and medulla
Explanation:Brain stem is the base of the brain that connects the brain to the spinal cord. It consists of the mid brain, pons and medulla oblongata.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 96
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 97
Incorrect
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Which one of the following features is least associated with primary hyperparathyroidism?
Your Answer: Depression
Correct Answer: Sensory loss
Explanation:The signs and symptoms of primary hyperparathyroidism are those of hypercalcemia. They are classically summarized by stones, bones, abdominal groans, thrones and psychiatric overtones.
Stones refers to kidney stones, nephrocalcinosis, and diabetes insipidus (polyuria and polydipsia). These can ultimately lead to renal failure.
Bones refers to bone-related complications: osteitis fibrosa cystica, osteoporosis, osteomalacia, and arthritis.
Abdominal groans refers to gastrointestinal symptoms of constipation, indigestion, nausea and vomiting. Hypercalcemia can lead to peptic ulcers and acute pancreatitis.
Thrones refers to polyuria and constipation
Psychiatric overtones refers to effects on the central nervous system. Symptoms include lethargy, fatigue, depression, memory loss, psychosis, ataxia, delirium, and coma.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 98
Correct
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Which of the following is not innervated by the parasympathetic nerve supply?
Your Answer: Radial muscle of iris
Explanation:The sphincter pupillae is supplied by the parasympathetic fibers from the Edinger Westphal nucleus of the oculomotor nerve. The dilator pupillae (radial muscle) is supplied by the postganglionic fibers of the superior cervical sympathetic ganglion. The parasympathetic nerve supply to the salivary glands originate in the parasympathetic nucleus of the facial nerve (superior salivatory nucleus) and the glossopharyngeal nerve (inferior salivatory nucleus). The parasympathetic preganglionic fibers originate in the dorsal nucleus of the vagus nerve and descend into the thorax in the vagus nerve. The fibers terminate by synapsing with postganglionic neurons in the cardiac plexuses. Postganglionic fibers terminate on the sinoatrial and atrioventricular nodes and on the coronary arteries Parasympathetic supply to the stomach is via the vagus nerve.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 99
Correct
-
The axons of which neurons serve as the only output from the cerebellar cortex?
Your Answer: Purkinje
Explanation:The cerebellar cortex consist of 3 layers. The molecular layer, the granule cell layer and the Purkinje cell layer in the middle. The Purkinje cells project into the deep cerebellar nuclei. They are the only output cells of the cerebellar cortex.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 100
Correct
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Where is angiotensinogen produced?
Your Answer: Liver
Explanation:Angiotensin is a peptide hormone that causes vasoconstriction and a subsequent increase in blood pressure. Angiotensin also stimulates the release of aldosterone from the adrenal cortex. Aldosterone promotes sodium retention in the distal nephron, in the kidney, which also drives blood pressure up. It is derived from the precursor molecule angiotensinogen, a serum globulin produced in the liver.
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This question is part of the following fields:
- Medicine
- Renal
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Question 101
Correct
-
The predominant receptors in the hearts conduction system are?
Your Answer: Β1
Explanation:All of the components of the intrinsic conduction system contain autorhythmic cells that spontaneously depolarize. In the absence of extrinsic neural or hormonal influences, the SA node pacing rate would be about 100 beats per minute (bpm). The heart rate and cardiac output, however, must vary in response to the needs of the body’s cells for oxygen and nutrients under varying conditions. In order to respond rapidly to changing requirements of the body’s tissues, the heart rate and contractility are regulated by the autonomic nervous system (ANS), hormones, and other factors. The ANS has two interacting systems: the sympathetic and parasympathetic systems.
Sympathetic receptors: There are two types of adrenergic receptors: β and α. In the cardiovascular system there are β1, β2, α1, and α2 adrenergic receptors. β1 adrenergic receptors are expressed in the heart conduction system (in the SA node, AV node, and on atrial and ventricular cardiomyocytes). The activation of β1 receptors increases heart rate (via the SA node), and contractility.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 102
Correct
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Question 103
Correct
-
Which of the following statements is not true about mitochondrial chromosomes?
Your 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 104
Incorrect
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Dynein proteins transmit polypeptides/proteins in which direction?
Your Answer: From cell body to axonal terminals (anterograde)
Correct Answer: From axons terminals to cell body (retrograde)
Explanation:The majority of axonal proteins are synthesised in the cell body and transported along the axons. Microtubules run along the length of the axon and provide tracks for transportation. Kinesin and Dynein are motor proteins that transport proteins and other organelles. Kinesin moves forward or anterograde transport from cell body to axon, whereas Dynein moves retrograde from axon to cell body.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 105
Correct
-
The breakdown of superoxide is catalysed by which enzyme?
Your Answer: Superoxide dismutase
Explanation:As superoxide is toxic, nearly all organisms living in the presence of oxygen contain isoforms of the superoxide-scavenging enzyme superoxide dismutase, or SOD. SOD is an extremely efficient enzyme; it catalyses the neutralization of superoxide nearly as quickly as the two can diffuse together spontaneously in solution.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 106
Correct
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AV valves open during?
Your Answer: Early diastole
Explanation:The cardiac cycle refers to a complete heartbeat from its generation to the beginning of the next beat, and so includes the diastole, the systole, and the intervening pause.The first stage, diastole, is when the semilunar valves (the pulmonary valve and the aortic valve) close, the atrioventricular (AV) valves (the mitral valve and the tricuspid valve) open, and the whole heart is relaxed. The second stage, atrial systole, is when the atrium contracts, and blood flows from atrium to the ventricle.The third stage, isovolumic contraction is when the ventricles begin to contract, the AV and semilunar valves close, and there is no change in volume. The fourth stage, ventricular ejection, is when the ventricles are contracting and emptying, and the semilunar valves are open. During the fifth stage, isovolumic relaxation time, pressure decreases, no blood enters the ventricles, the ventricles stop contracting and begin to relax, and the semilunar valves close due to the pressure of blood in the aorta.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 107
Correct
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Which of the following is first to rise following myocardial infarction?
Your Answer: Myoglobin
Explanation:Myoglobin, is a sensitive indicator of muscle injury and is first to rise following MI within two hours but is nonspecific.Troponin and CK-MB both begin to rise approximately three hours after MI. The cardiac troponins T and I which are released within 4–6 hours of an attack of MI and remain elevated for up to 2 weeks, have nearly complete tissue specificity and are now the preferred markers for assessing myocardial damage.Lactate dehydrogenase (LDH) begins to rise approximately 12 hours after MI.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 108
Incorrect
-
With regard to the spleen which of the following has the correct match?
Your Answer: Splenic cords - white pulp
Correct Answer: Periarteriolar lymphoid sheets - T lymphocytes
Explanation:The spleen consists of:Red pulp – responsible for mechanical filtration of red blood cells. Red pulp contains sinusoids, which are filled with blood, splenic cords of reticular fibers and a marginal zoneWhite pulp – responsible for active immune response through humoral and cell-mediated pathways. Composed of nodules, called Malpighian corpuscles. These are composed of: lymphoid follicles, rich in B-lymphocytes and periarteriolar lymphoid sheaths, rich in T-lymphocytes
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This question is part of the following fields:
- Haematology
- Medicine
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Question 109
Correct
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Which one of the following ECG findings is least associated with digoxin use?
Your Answer: Prolonged QT interval
Explanation:Digoxin ECG features:• ST depression (‘reverse tick’)• flattened/inverted T waves• Prolonged PR interval• short QT interval• arrhythmias e.g. AV block, bradycardia, ventricular tachycardia or fibrillation (for example paroxysmal atrial tachycardia with A-V block – so-called PAT with block) is said to be pathognomonic (i.e. diagnostic) of digoxin toxicity.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 110
Correct
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An 18 year old boy, thin with a tall stature, and a high arched palate arrives at the hospital with a spontaneous pneumothorax. He is accompanied by his brother who has a similar appearance. You suspect Marfan's Syndrome. The gene encoding which of the following proteins is defective in this condition?
Your Answer: Fibrillin-1
Explanation:A variety of proteins compose the structure of microfibrils, the most prominent of which are the two fibrillins. Fibrillin-1 a scaffolding protein is encoded by FBN1 on human chromosome 15q21 and fibrillin-2 is encoded by FBN2 on 5q23. Mutations in FBN1 produce Marfan syndrome, a pleiotropic autosomal dominant connective tissue disorder with prominent manifestations in the skeleton, eye and cardiovascular system. A number of conditions related to Marfan syndrome are also due to FBN1 mutations.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 111
Incorrect
-
What is the average life span of neutrophils?
Your Answer: 7 days
Correct Answer: 24 hours
Explanation:The average lifespan of inactivated human neutrophils in the circulation has been reported by different approaches to be between 5 and 90 hours.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 112
Incorrect
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A 25-year-old male presented to accident and emergency 4 days ago, following an intentional paracetamol overdose. He had taken 20x 500mg tablets, all at once. He denies any alcohol intake. Blood investigations 4 hours after ingestion showed:Paracetamol: 14 mg/lINR: 1Liver enzymes: No abnormality detectedBilirubin: Mild elevationHe was seen by the mental health team and discharged. The blood investigations were repeated:Bilirubin: Within normal limitsUrea: 21 mmol/lCreatinine: 300 µmol/lWhat is the likely cause of these results?
Your Answer: Spurious blood result
Correct Answer: Delayed paracetamol nephrotoxicity
Explanation:The most likely cause for these results is delayed paracetamol nephrotoxicity.The blood investigations of this patient are highly suggestive of acute kidney injury. Paracetamol overdose is well known to cause hepatotoxicity, but not for its delayed nephrotoxicity, especially in significant overdose. Appropriate monitoring of a patient’s blood tests is important.Management:NAC (N-Acetyl cysteine) has a clear role in preventing acetaminophen-induced liver necrosis. Although NAC has not been proven to be harmful to the kidney, its role in patients without hepatoxicity and only isolated renal dysfunction is uncertain.Other options:-There are no features in the history that are suggestive of dehydration and pre-renal AKI presenting in this manner in a 25-year-old would be very unusual.- Minimal change nephropathy typically presents with a nephrotic picture of kidney injury.- Berger’s more commonly presents with isolated haematuria.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 113
Correct
-
During which phase of the cell cycle does transcription of DNA synthesis molecules occur?
Your Answer: S
Explanation:DNA synthesis occurs in the S phase of the cell cycle. In the G1 phase the cell prepares to divide. In G2 the cellular organelles divide and in the M phase mitosis occur. In the G0 phase the cell becomes quiescent and does not divide further.
Interphase is composed of G1 phase (cell growth), followed by S phase (DNA synthesis), followed by G2 phase (cell growth). At the end of interphase comes the mitotic phase, which is made up of mitosis and cytokinesis and leads to the formation of two daughter cells.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 114
Correct
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An exaggerated response to a noxious stimulus is called:
Your Answer: Hyperalgesia
Explanation:Allodynia is the sensation of pain following non-painful stimulation.
Hyperalgesia is enhanced intensity of pain sensation.
Causalgia is a constant burning pain resulting from peripheral nerve injury.
Hyperesthesia is the abnormal increase in sensitivity to stimuli of sense.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 115
Correct
-
What are the major motor proteins that interact with microtubules?
Your Answer: Kinesin and dynein
Explanation:The major motor proteins that interact with microtubules are kinesin, which usually moves toward the (+) end of the microtubule, and dynein, which moves toward the (−) end.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 116
Incorrect
-
von Willebrand factor stabilises which clotting factor?
Your Answer: Factor V
Correct Answer: Factor VIII
Explanation:Von Willebrand factor’s primary function is binding to other proteins, in particular factor VIII, and it is important in platelet adhesion to wound sites. It is not an enzyme and, thus, has no catalytic activity. Factor VIII degrades rapidly when not bound to vWF. Factor VIII is released from vWF by the action of thrombin.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 117
Incorrect
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A 74 year old man presents with 12 kg weight loss and persistent back pain that is unrelated to activity for the past several months. Laboratory findings show :WCC: 6.7 x 109/l (5.4 neutrophils, 1.2 lymphocytes and 0.2 monocytes)Haemoglobin: 11.2 g/dlhaematocrit: 33.3%MCV: 88 flPlatelet count: 89 x 109/l.The biochemistry shows:sodium 144 mmol/lpotassium 4.5 mmol/lchloride 100 mmol/lbicarbonate 26 mmol/lurea 14 mmol/lcreatinine 90 μmol/la glucose of 5.4 mmol/l.A CT scan of the spine reveals scattered 0.4 to 1.2 cm bright lesions in the vertebral bodies.Which of the following additional laboratory test findings is he most likely to have?
Your Answer: Blood culture positive for Neisseria gonorrhoeae
Correct Answer: Serum prostate specific antigen of 35 microgram/l
Explanation:Old age, persistent backache, weight loss, and osteosclerotic lesions make prostatic adenocarcinoma the most likely diagnosis. The sequelae include severe pain, pathological fractures, hypercalcemia and cord compression. Prostatic adenocarcinoma is detected by elevated levels of prostate specific antigen. Positive serology for borrelia burgdorferi would hint at Lyme disease which does not cause osteosclerotic bone lesions, neither would Neisseria gonorrhoeae have such a presentation.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 118
Correct
-
Depolarization spreads rapidly through cardiac muscle fibers because of the presence of:
Your Answer: Gap junctions
Explanation:The cardiac muscles have gap junctions in between the cells. They allow for the formation of low resistance passages, which allow ions to diffuse through every muscle fiber rapidly and result in the cardiac muscles functioning as a syncytium, without any protoplasmic bridges involved.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 119
Correct
-
Which of the following refers to the process of decoding messenger RNA into an amino acid sequence?
Your Answer: Translation
Explanation:Messenger RNA (mRNA) is decoded in a ribosome, outside the nucleus, to produce a specific amino acid chain, or polypeptide. This is known as translation and follows after the process transcription of DNA to RNA in the cell’s nucleus.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 120
Incorrect
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The lamina propria contains all of the following except:
Your Answer: Plasma cells
Correct Answer: Neutrophils
Explanation:The connective tissue of the lamina propria is very loose, allowing it to be very cell rich. The cell population of the lamina propria is variable and can include, for example, fibroblasts, lymphocytes, plasma cells, macrophages, eosinophilic leukocytes, and mast cells. It provides support and nutrition to the epithelium, as well as the means to bind to the underlying tissue.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 121
Correct
-
Where is Basic Electrical rhythm initiated
Your Answer: Interstitial cells of cajal
Explanation:The interstitial cells of Cajal are specialized pacemaker cells located in the wall of the stomach, small intestine, and large intestine. These cells are connected to the smooth muscle via gap junctions and the myenteric plexus. The cell membranes of the pacemaker cells undergo a rhythmic depolarization and repolarization from -65mV to -45mV. This rhythm of depolarization-repolarization of the cell membrane creates a slow wave known as a basic electrical rhythm (BER), and it is transmitted to the smooth muscle cells.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 122
Correct
-
A 70-year-old woman is having trouble in speaking following a stroke. Her limbs are paralyzed, both left upper and lower limbs. Which anatomical site is most likely affected?
Your Answer: Internal capsule
Explanation:– The given scenario is typical of lesion in internal capsule. – Memory impairment is caused by a hippocampal lesion, – Impairment of arousal, facial paresis, visual field defect, facial paresis, hemiataxia, and hemispacial neglect are just some of the conditions caused by thalamic lesion. – Brainstem stroke on the other hand causes breathing abnormality, altered consciousness, and blood pressure disorder.
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This question is part of the following fields:
- Geriatrics
- Medicine
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Question 123
Incorrect
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Which one of the following nerve fibers is involved in proprioception?
Your Answer: C fiber
Correct Answer: An α fiber
Explanation:Proprioception, also known as kinaesthesia, is the sense through which humans perceive their own position and movements. α nerve fibers are specifically involved in transmitting proprioception stimuli.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 124
Correct
-
Which of the following is NOT true of the parasympathetic control of the heart?
Your Answer: It can be blocked by beta blockers
Explanation:Parasympathetic fibers do not innervate the Beta receptors on the heart. They are innervated by the sympathetic nerve fibers. Then a beta blocker such as propranolol will block the sympathetic outflow and increase the parasympathetic tone of the heart.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 125
Correct
-
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: 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
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Question 126
Incorrect
-
Where is Vitamin B12 mainly stored in the body?
Your Answer: Distal ileum
Correct 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 127
Incorrect
-
Regarding the cardiac muscle striations as viewed under the microscope, which areas are dark?
Your Answer: I band and z line
Correct Answer: A band and z line
Explanation:Dark bands: a, h. Dark line: z. Clear band: i, m
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 128
Correct
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Question 129
Correct
-
Which of the following has the shortest duration:
Your 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
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Question 130
Incorrect
-
Which of the following happens when anterograde neurons are stimulated?
Your Answer: Smooth muscle contraction ahead of the stimulus
Correct Answer: Smooth muscle relaxation ahead of the stimulus
Explanation:Nitric oxide is thought to act as an anterograde neurotransmitter. Nitric oxide causes relaxation of smooth muscles ahead of the stimulus. Clinically it is used as a potent vasodilator.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 131
Incorrect
-
Which of the following statements is true regarding herpes simplex virus type I:
Your Answer: It remains latent in the cervical dorsal root ganglion.
Correct Answer: More than half of the population is infected.
Explanation:HSV-1 is often acquired orally during childhood. It may also be sexually transmitted, including contact with saliva, such as kissing and mouth-to-genital contact (oral sex). HSV-2 is primarily a sexually transmitted infection, but rates of HSV-1 genital infections are increasing. HSVs may persist in a quiescent but persistent form known as latent infection, notably in neural ganglia. HSV-1 tends to reside in the trigeminal ganglia, while HSV-2 tends to reside in the sacral ganglia, but these are tendencies only, not fixed behaviour. The virus can be reactivated by illnesses such as colds and influenza, eczema, emotional and physical stress, gastric upset, fatigue or injury, by menstruation and possibly exposure to bright sunlight. Genital Herpes may be reactivated by friction. Shingles is due to a reactivation of varicella zoster virus (VZV).
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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Question 132
Correct
-
Majority of gastrinomas are found in the:
Your Answer: Duodenum
Explanation:A gastrinoma is a tumour in the pancreas or duodenum that secretes excess of gastrin leading to ulceration in the duodenum, stomach and the small intestine. It is usually found in the duodenum, although it may arise in the stomach or pancreas. Those occurring in the pancreas have a greater potential for malignancy. Most gastrinomas are found in the gastrinoma triangle; this is bound by the junction of cystic and common bile ducts, junction of the second and third parts of the duodenum, and the junction of the neck and body of the pancreas.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 133
Incorrect
-
All of the following constitute small intestinal brush border enzymes except:
Your Answer: Glucoamylase
Correct Answer: Alpha-amylase
Explanation:The final step in digestion of carbohydrates, which is conversion of disaccharides to absorbable monosaccharides occurs on the small intestinal epithelial cells. The enzymes responsible for this final stage of digestion are not freely found in the intestinal lumen, but they are found as integral membrane proteins in the plasma membrane of the epithelial cell. The apical plasma membrane of the intestinal epithelial cell has numerous microvilli which extend from the cell known as the brush border. Thus, the enzymes embedded in those microvilli are referred to as brush border enzymes. All these enzymes except alfa amylase are brush border enzymes. Alfa amylase is secreted by pancreatic acinar cells.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 134
Correct
-
A 68 year old male presented with swelling in the lower pole of his parotid gland. It is revealed that this has been ongoing for the past 10 years. Upon examination, the swelling is firm in consistency. From the list of options, choose the most probable diagnosis for this patient.
Your Answer: Pleomorphic adenoma
Explanation:A pleomorphic adenoma is also called a benign mixed tumour – this is the most common tumour of the parotid gland. It also causes over a third of all submandibular tumours. This type of a tumour is slow-growing and has no symptoms, which means it has great malignant potentiality.
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This question is part of the following fields:
- Geriatrics
- Medicine
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Question 135
Incorrect
-
Pepsinogens are inactive pepsin precursors which are activated by
Your Answer: Pancreatic juice
Correct Answer: Gastric acid
Explanation:Pepsinogen is converted to pepsin by the action of hydrochloric acid i.e. gastric acid
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 136
Correct
-
The main reason for the prolonged effect of the withdrawal reflex is:
Your Answer: Multiple connections between afferent and efferent neurons
Explanation:The withdrawal reflex is a spinal reflex that protects the body from harmful stimuli. Spinal reflexes are mostly monosynaptic and are mediated by a simple reflex arc. Withdrawal reflex is mediated by a polysynaptic reflex resulting in stimulation of many motor neurons in order to establish a quick and prolonged response.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 137
Correct
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Question 138
Correct
-
During which phase of the cell cycle does DNA synthesis occur?
Your Answer: S
Explanation:DNA synthesis occurs in the S phase of the cell cycle. In the G1 phase the cell prepares to divide. In G2 the cellular organelles divide and in the M phase mitosis occur. In the G0 phase the cell becomes quiescent and does not divide further
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This question is part of the following fields:
- Genetics
- Medicine
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Question 139
Correct
-
A 50-year-old woman diagnosed with non-Hodgkin's Lymphoma is about to be started on the CHOP regimen (cyclophosphamide, hydroxydaunorubicin, vincristine, and prednisolone). Her pre-chemotherapy blood investigations show:Hb: 11.8 g/dlPlatelets: 423 x 109/lWBC: 11.2 x 109/lNa+: 143 mmol/lK+: 3.9 mmol/lUrea: 6.2 mmol/lCreatinine: 78 μmol/lUric acid: 0.45 mmol/lCiprofloxacin is prescribed in addition to the CHOP regimen to reduce the risk of neutropenic sepsis. Which of the following drugs should be added to lower the risk of other complications?
Your Answer: Allopurinol
Explanation:Tumour lysis syndrome (TLS) occurs most notably in patients with haematological malignancies including, Non-Hodgkin’s Lymphoma (NHL) and Acute Lymphocytic Leukaemia (ALL).Risk factors for TLS include:• Large tumour burden• Sensitivity of the tumour to chemotherapy• Rapid tumour growth rateTLS is characterized by:• Hyperuricemia• Hyperkalaemia• Hyperphosphatemia• HypocalcaemiaTreatment of TLS:• Allopurinol: It is a xanthine oxidase inhibitor, it reduces the conversion of nucleic acid by-products to uric acid. Thus, it prevents urate nephropathy and subsequent oliguric renal failure. Note: dose reduction is essential in renal failure or if given along with mercaptopurine or azathioprine.Alternatives to Allopurinol: Febuxostat; Rasburicase are useful in patients with hyperuricemia.• Hydration• Diuresis: Should be considered in well hydrated patients with insufficient urine output. Furosemide to be considered in normo-volemic patients with hyperkalaemia. Urine alkalization can be considered for promoting alkaline diuresis.• Treatment of electrolyte imbalances including hyperkalaemia, hyperphosphatemia, and hypocalcaemia.• Dialysis can be considered in refractory cases.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 140
Incorrect
-
The complete oxidation of 1 molecule of glucose to CO2 and H20 produces a total of __ATP.
Your Answer: 28
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 141
Incorrect
-
Which of the following statements is true of the beta- lactams:
Your Answer: Modifications of the central structure results in the resistance to bacterial penicillinase
Correct 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 142
Incorrect
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Question 143
Incorrect
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The following are Gram positive rods:
Your Answer: Proteus
Correct 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 144
Incorrect
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Which of the following suggests the presence of mitral regurgitation as well as mitral stenosis?
Your Answer: Raised JVP
Correct Answer: Displaced apex beat
Explanation:Mitral stenosis on its own does not lead to left ventricular dilatation and hence a displaced apex beat. Thus a displaced apex beat is suggestive of mixed mitral disease. The other options occur in mitral stenosis.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 145
Incorrect
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A 34-year-old man was brought to the ER following a road-traffic-accident. An X-ray of his left thigh revealed a fractured shaft of the left femur. He has a known history of opioid abuse. You are called to the ward to assess him after he becomes unwell. Which of the following clinical features are NOT compatible with a diagnosis of opioid withdrawal?
Your Answer: Yawning
Correct Answer: Hypothermia
Explanation:Among the options provided, hypothermia is not a symptom of opioid withdrawal.Symptoms of opioid withdrawal include dysphoric mood, yawning, insomnia, muscle aches, lacrimation/rhinorrhoea, papillary dilatation, piloerection, fever, sweating, nausea/vomiting, diarrhoea.If the patient is having an opioid withdrawal reaction, then give 10 mg of methadone syrup and wait about 60 min to determine its effect.COWS (Clinical Opioid Withdrawal Scale) assessment for opioid withdrawal is commonly used to determine the severity of opioid withdrawal.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 146
Correct
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Which of the following diseases have antibodies available for treatment of the condition.
Your Answer: None of these
Explanation:There is no specific treatment for hepatitis A. Recovery from symptoms following infection may be slow and may take several weeks or months. The hepatitis A vaccine is effective for prevention and appears to be effective for life.Acute hepatitis B infection does not usually require treatment and most adults clear the infection spontaneously. Early antiviral treatment may be required in fewer than 1% of people, whose infection takes a very aggressive course (fulminant hepatitis) or who are immunocompromised. Although none of the available drugs can clear the infection, they can stop the virus from replicating, thus minimizing liver damage.There is no specific treatment for measles. Most people with uncomplicated measles will recover with rest and supportive treatment. In developed countries, children are immunized against measles at 12 months, generally as part of a three-part MMR vaccine (measles, mumps, and rubella). The vaccination is generally not given before this age because such infants respond inadequately to the vaccine due to an immature immune system. Treatment after rabies exposure can prevent the disease if administered promptly, generally within 10 days of infection. The Centres for Disease Control and Prevention recommends people receive one dose of human rabies immunoglobulin (HRIG) and four doses of rabies vaccine over a 14-day period.
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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Question 147
Correct
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Cyclic AMP is formed from ATP via which enzyme
Your Answer: Adenylate cyclase
Explanation:Cyclic AMP is synthesized from ATP by adenylate cyclase located on the inner side of the plasma membrane and anchored at various locations in the interior of the cell.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 148
Incorrect
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What is the effect of oxytocin on the breast?
Your Answer: Inhibits milk ejection
Correct Answer: Milk ejection
Explanation:Oxytocin is a peptide hormone and neuropeptide, produced by the hypothalamus and released by the posterior pituitary. It causes the milk ejection or let-down reflex, causing the milk to be transported to the subareolar sinuses, allowing it to be released through the nipple. This response is initiated by the act of suckling by the baby, but it can be conditioned to be triggered by different stimuli.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 149
Incorrect
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Which substance is produced by anterograde neurons?
Your Answer: Cholecystokinin
Correct Answer: Nitric oxide
Explanation:Nitric oxide is thought to act as an anterograde neurotransmitter. Classically in the peripheral nervous system, it diffuses from a presynaptic nerve ending to the post synaptic effecter cell which is mainly smooth muscle cells in the gastrointestinal, respiratory and urogenital tracts.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 150
Incorrect
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Which of the toxin secretion pathways in the cell membrane of gram– bacteria delivers the toxin extracellular in a 2 stage process to the host?
Your Answer: VI
Correct Answer: II
Explanation:Gram negative bacteria contain two membranes and there are about six specialized secretion systems. The secreted proteins play a key role in pathogenesis. Type II secretion systems (T2SS) are conserved in most Gram-negative bacteria, where they transport proteins from the periplasm into the extracellular environment. Because the T2SS channel is only found in the outer membrane, proteins secreted through this apparatus must first be delivered to the periplasm via the Sec or Tat secretion pathways and then to the extracellular environment making it a two-stage process.
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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SESSION STATS - PERFORMANCE PER SPECIALTY
