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Question 1
Incorrect
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β-blockers are used in the treatment of angina because they have which one of the following properties?
Your Answer: Increase the preload
Correct Answer: Decrease the heart rate and myocardial contractility
Explanation:The cardiovascular effects of β-adrenoceptor block result from reduction of the sympathetic drive which includes reduced heart rate (automaticity) and reduced myocardial contractility (rate of rise of pressure in the ventricle). This will lead to reduced cardiac output and an overall fall in oxygen consumption.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 2
Correct
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The blood supply to the greater curvature of the stomach is via the:
Your Answer: Right and left gastro-epiploic arteries
Explanation:The blood supply to the greater curvature of the stomach is via the left and the right gastro-epiploic arteries branching from the splenic artery near the hilum.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 3
Correct
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Which of the following forms the language areas of the cerebral cortex?
Your Answer: All of the above
Explanation:Broca’s area, Wernicke’s area, the submarginal sulcus and the angular gyrus all form the language areas of the cerebral cortex.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 4
Correct
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The process by which depolarization of the muscle fiber initiates contraction is called?
Your Answer: Action potential
Explanation:This process is known as an action potential. Upon generation of an action potential when depolarization reaches threshold, it spreads throughout the muscle fiber, resulting in generation of an excitation-contraction coupling leading to contraction of the muscle.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 5
Incorrect
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Hydroxyl radicals are broken down by which of the following substance?
Your Answer: Hydroxyl reductase
Correct Answer: Antioxidants
Explanation:Unlike superoxide, which can be detoxified by superoxide dismutase, the hydroxyl radical cannot be eliminated by an enzymatic reaction but it is believed can be counteracted by antioxidants.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 6
Incorrect
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Which of the following is a product of D cells
Your Answer: Gastrin releasing peptide (grp)
Correct Answer: Somatostatin
Explanation:Somatostatin is secreted by D cells, HCL and intrinsic factor secreted by parietal cells. Trefoil peptides are secreted by mucus secreting goblet cells and gastrin releasing peptide (grp) by post-ganglionic fibers of the vagus nerve (which innervate the G cells of the stomach).
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 7
Incorrect
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Concerning coronary arteries, what is the net effect of B2 stimulation on the heart (e.g. Running athlete)?
Your Answer: Vasodilation directly
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 8
Correct
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The positive inotropic effect of digoxin is due to?
Your Answer: Inhibition of the sodium potassium ATPase in the myocardium
Explanation:Digitalis compounds are potent inhibitors of cellular Na+/K+-ATPase. This ion transport system moves sodium ions out of the cell and brings potassium ions into the cell. By inhibiting the Na+/K+-ATPase, cardiac glycosides cause the intracellular sodium concentration to increase. This then leads to an accumulation of intracellular calcium via the Na+/Ca++ exchange system. In the heart, increased intracellular calcium causes more calcium to be released by the sarcoplasmic reticulum, thereby making more calcium available to bind to troponin-C, which increases contractility (inotropy).
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 9
Incorrect
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Where is thyroglobulin produced?
Your Answer: Hypothalamus
Correct Answer: Thyrocytes
Explanation:Thyroglobulin, or Tg, is a protein that functions as the precursor to thyroid hormones. It is synthesized by thyrocytes and then secreted into the colloid. It also functions as a negative-feedback regulator of thyroid hormone biosynthesis.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 10
Incorrect
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During strenuous exercise the following arterial change can take place in a fit athlete:
Your Answer: pH can decrease
Correct Answer: No change takes place
Explanation:The changes which occur in arterial pH, PO2 and PCO2 values during exercise are usually small. Arterial PO2 often rises slightly because of hyperventilation although it may eventually fall at high work rates. During vigorous exercise, when sufficient oxygen for flux through the Krebs cycle is not available, the increased reliance on glycolysis results in increased accumulation of lactic acid, which initially leads to an increase in PaCO2 . However, this is counteracted by the stimulation of ventilation and as a result PaCO2 is decreased. This provides some respiratory compensation for further lactic acid production and prevents a decline in blood pH, which remains nearly constant during moderate exercise.
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This question is part of the following fields:
- Medicine
- Respiratory
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Question 11
Incorrect
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Xanthines such as caffeine and theophylline are positively inotropic due to:
Your Answer: Circulating catecholamines
Correct Answer: Inhibition of cAMP breakdown
Explanation:Xanthines exert their positive inotropic effect by inhibiting the breakdown of the cAMP resulting in stronger and sustained contractions.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 12
Incorrect
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Around 30 patients have been admitted to the hospital following a suspected chemical attack in the city. The patients are extremely unwell, with symptoms of excessive salivation, lacrimation, diarrhoea, and emesis. Sarin gas was suspected as the most likely agent used in the attack. What is the mechanism of action of this chemical agent?
Your Answer: Anti-cholinergic
Correct Answer: Inhibition of acetylcholinesterase
Explanation:Sarin acts by inhibiting acetylcholinesterase.Sarin gas is a highly toxic synthetic organophosphorus compound which causes inhibition of the enzyme acetylcholinesteraseSarin gas is a highly toxic synthetic organophosphorus compound which causes inhibition of the enzyme acetylcholinesterase. This results in high levels of acetylcholine (ACh).The effects of excessive ACh can be remembered by the mnemonic DUMBELLS:DiarrhoeaUrinationMiosis/muscle weaknessBronchorrhea/BradycardiaEmesisLacrimationSalivation/sweatingOrganophosphate insecticide poisoning:One of the effects of organophosphate poisoning is inhibition of acetylcholinesteraseFeatures can be predicted by the accumulation of acetylcholine (mnemonic = SLUD)SalivationLacrimationUrinationDefecation/diarrhoeacardiovascular: hypotension, bradycardiamiosis, muscle fasciculation.Organophosphate poisoning is treated with the anti-muscarinic atropine.
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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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What is troponin?
Your Answer: A substance produced by pulmonary vascular endothelium
Correct Answer: A component of thin filaments
Explanation:Skeletal muscle cytoplasmic proteins include myosin and actin (also known as thick and thin filaments, respectively) which are arranged in a repeating unit called a sarcomere. Troponin is a component of thin filaments (along with tropomyosin), and is the protein to which calcium binds.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 14
Correct
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Regarding blood supply to the heart;
Your Answer: Coronary arteries fill as the heart relaxes
Explanation:The heart muscles acts like the skeletal muscle in the fact that it also compress the vessels during contraction. As the pressure in the ventricle is slightly greater than in the aorta the coronary vessels collapse during systole. Blood flows through them during the diastole phase of contraction.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 15
Correct
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A 85 year old male with a history of faecal impaction, who lived at a nursing-home presented with abdominal pain and distension, confusion and agitation. Which of the following is the first step of the management.
Your Answer: Phosphate enema
Explanation:The most probable cause for this presentation is faecal impaction following constipation, which is common among old people who live in nursing-homes. There can be number of reason for constipation in old age, including medications, endocrine and metabolic diseases, neurologic disorders, myopathic disorders, dietary habits etc. Enemas are a way of removing impacted faeces, which helps rectal evacuation.
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This question is part of the following fields:
- Geriatrics
- Medicine
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Question 16
Correct
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Where is Vitamin B12 mainly stored in the body?
Your Answer: Liver
Explanation:The total amount of vitamin B12 stored in body is about 2–5 mg in adults. Around 50% of this is stored in the liver. Approximately 0.1% of this is lost per day by secretions into the gut, as not all these secretions are reabsorbed.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 17
Incorrect
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A 65-year-old man presents to you three weeks after initiating metformin for type 2 diabetes mellitus. His body mass index is 27.5 kg/m^2. At a dose of 500mg TDS the patient has experienced significant diarrhoea. Even on reducing the dose to 500mg BD his symptoms persisted. What is the most appropriate next step in this patient?
Your Answer: Switch to gliclazide 40mg od
Correct Answer: Start modified release metformin 500mg od with evening meal
Explanation:Here, the patient seems to be intolerant to standard metformin. In such cases, modified-release preparations is considered as the most appropriate next step. There is some evidence that these produce fewer gastrointestinal side-effects in patients intolerant of standard-release metformin.Metformin is a biguanide and reduces blood glucose levels by decreasing the production of glucose in the liver, decreasing intestinal absorption and increasing insulin sensitivity. Metformin decreases both the basal and postprandial blood glucose.Other uses: In Polycystic Ovarian Syndrome (PCOS), Metformin decreases insulin levels, which then decreases luteinizing hormone and androgen levels. Thus acting to normalize the menstruation cycle.Note:Metformin is contraindicated in patients with severe renal dysfunction, which is defined as a glomerular filtration rate (GFR) less than 30 ml/min/1.732m2. Metformin overdose has been associated with hypoglycaemia and lactic acidosis, for this reason, it has a black box warning for lactic acidosis.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 18
Incorrect
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In terms of relative steroid potency, how much prednisone is equivalent to 100mg hydrocortisone?
Your Answer: 50mg
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 19
Incorrect
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Regarding Polymerase Chain Reaction, all are true except:
Your Answer: DNA is initially denatured by heat into single stranded DNA prior to cooling
Correct Answer: There is a linear rise of DNA copies during amplification.
Explanation:All are true except there is a linear rise of DNA copies during amplification. There is an exponential rise in amplification of DNA.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 20
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 21
Incorrect
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The telomerase is capable of adding several more repeats of telomeres at which end of the guanosine rich region.
Your Answer: 2nd end
Correct Answer: 3rd end
Explanation:Telomerase is a reverse transcriptase that uses the RNA template to synthesize DNA in the 5th-3rd direction resulting in extension of the 3rd end and then translocates it to the newly synthesized end. The GT rich strand is thus elongated.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 22
Incorrect
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Which of the following statements is the most characteristic of primary Raynaud's phenomena?
Your Answer: Nail fold capillary scope shows dilated vessels
Correct Answer: Fingers are symmetrically involved during an attack
Explanation:A typical attack may last less than an hour but can also persist for longer. In primary Raynaud’s, attacks are more likely symmetric, episodic, and without evidence of peripheral vascular disease. Patients more commonly have a negative ANA and normal inflammatory markers. There should be no evidence of tissue gangrene, digital pitting, or tissue injury in primary Raynaud’s. In contrast, patients with secondary Raynaud’s will describe attacks that are more frequent, painful, often asymmetric and may lead to digital ulcerations.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 23
Incorrect
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Cells mediating innate immunity include:
Your Answer: T lymphocytes
Correct 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 24
Incorrect
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Where would one find pericytes around endothelial cells?
Your Answer: Pre-capillary venules
Correct Answer: Post-capillary venules
Explanation:Pericytes release a wide variety of vasoactive agents which regulate the flow through the junction between endothelial cells.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 25
Incorrect
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A 25-year-old female presents to the emergency department with severe breathlessness and tinnitus. She is under treatment for asthma and depression with albuterol and amitriptyline respectively.On examination, she seems agitated with a BP of 100/44, a pulse rate of 112 bpm, a respiratory rate of 30 cycles/min, and a temperature of 37.8'C.An arterial blood gas performed reveals:pH: 7.48 (7.36 – 7.44)pO2: 11.2 kPa (11.3 – 12.6 kPa)pCO2: 1.9 kPa (4.7 – 6.0 kPa)Bicarbonate: 13 mmol/l (20 – 28 mmol/L)What is the most probable diagnosis?
Your Answer: Acute asthma exacerbation
Correct Answer: Salicylate poisoning
Explanation:The blood gas analysis provided above is suggestive of a mixed respiratory alkalosis and metabolic acidosis characteristic of salicylate overdose.Pathophysiology:The direct stimulation of the cerebral medulla causes hyperventilation and respiratory alkalosis.As it is metabolized, it causes an uncoupling of oxidative phosphorylation in the mitochondria. Lactate levels then increase due to the increase in anaerobic metabolism. This, along with a slight contribution from the salicylate metabolites result in metabolic acidosis.Tinnitus is characteristic and salicylate ototoxicity may produce deafness. Other neurological sequelae include encephalopathy and agitation, seizures and CNS depression and coma. Cardiovascular complications include tachycardia, hypotension, and dysrhythmias (VT, VF, and asystole).
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 26
Correct
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Question 27
Incorrect
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The net effect of parathyroid hormone on calcium and phosphate homeostasis is?
Your Answer: Increase in Ca, no net effect on phosphate
Correct Answer: Increase in Ca, decrease in phosphate
Explanation:Parathyroid hormone’s main target organs are the kidneys, bone, and intestine. In the kidney, it decreases reabsorption of phosphate and increases calcium reabsorption. It also promotes absorption of calcium from bone. PTH release results in a small drop in serum phosphate concentrations.
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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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A 65-year-old man, after suffering from a pathological rib fracture, complains of recurrent infection. Bone marrow aspiration revealed a calcium level of 3.9 mmol/l and alkaline phosphatase level of 160u/l. What type of cell would be found in abundance in the marrow spear?
Your Answer: Plasma cells
Explanation:Multiple myeloma or plasma cell myeloma, is a cancer of plasma cells, responsible for producing antibodies. It often, presents early with no symptoms followed by bone pain and pathological fractures (metastases), raised calcium levels, bleeding, frequent infections, and anaemia. It usually occurs around the age of 61 and is more common in men than women.
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This question is part of the following fields:
- Geriatrics
- Medicine
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Question 29
Incorrect
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Which of the following vitamin deficiencies is associated with xerophthalmia?
Your Answer: Thiamine (B1)
Correct Answer: Vitamin A
Explanation:Xerophthalmia caused by a severe vitamin A deficiency is described by pathologic dryness of the conjunctiva and cornea. The conjunctiva becomes dry, thick and wrinkled. If untreated, it can lead to corneal ulceration and ultimately to blindness as a result of corneal damage.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 30
Correct
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Which three parietal cell agonists bind at the basolateral membrane at specific receptors respectively: M3 , H2 , CCK-B, to stimulate acid secretion?
Your Answer: Acetylcholine, histamine , gastrin
Explanation:The three agonists of parietal cell secretion are gastrin, acetylcholine and histamine. Parietal cells are responsible for the secretion of HCl and intrinsic factor.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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