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Question 1
Incorrect
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A 51-year-old real estate agent takes hydrocortisone 20mg in the mornings and 5mg at night for Addison’s disease. The endocrinology consultant would like her to take prednisolone instead. What dose of prednisolone should be started?
Your Answer: 10 mg
Correct Answer: 7 mg
Explanation:1mg Prednisolone = 4mg hydrocortisone, so the actual equivalent daily dose is 7mg.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 2
Correct
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The initial rapid depolarization in the action potential of cardiac muscle cells is due to:
Your Answer: Opening of voltage-gated Na+ channels
Explanation:The initial depolarization of the action potential in a cardiac muscle cell is due to the sodium current generated by opening of the voltage gated sodium channels leading to an influx of sodium ions into the cell and raising the membrane potential towards threshold.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 3
Incorrect
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A 50-year-old hypertensive male on phenytoin and clobazam for partial seizures is also taking lisinopril, cimetidine, sucralfate, and allopurinol. The last few drugs were added recently. He now presents with ataxia, slurred speech, and blurred vision.Which recently added drug is most likely to be the cause of his latest symptoms?
Your Answer: Sucralfate
Correct Answer: Cimetidine
Explanation:The symptoms of ataxia, slurred speech and blurred vision are all suggestive of phenytoin toxicity. Cimetidine increases the efficacy of phenytoin by reducing its hepatic metabolism.Phenytoin has a narrow therapeutic index (10-20 mg/L) and its levels are monitored by measuring the total phenytoin concentration.Cimetidine is an H2 receptor antagonist used in the treatment of peptic ulcers. It acts by decreasing gastric acid secretion.Cimetidine also has an inhibitory effect on several isoforms of the cytochrome enzyme system including the CYP450 enzymatic pathway. Phenytoin is metabolized by the same cytochrome P450 enzyme system in the liver. Thus, the simultaneous administration of both these medications leads to an inhibition of phenytoin metabolism and thus increases its circulating levels leading to phenytoin toxicity.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 4
Incorrect
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Activation of nitric oxide synthesis by endothelial cells is triggered by:
Your Answer: Acetylcholine
Correct Answer: All of the above
Explanation:Acetylcholine, histamine, bradykinin, vasoactive intestinal peptide (VIP) and shear stress on the endothelial cells causing the release of NO. NO is formed from arginine and causes vasodilatation of the blood vessels.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 5
Correct
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Inactive cellular marrow is called
Your Answer: Yellow marrow
Explanation:The two types of bone marrow are red marrow, which consists mainly of hematopoietic tissue, and yellow marrow, which is mainly made up of fat cells.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 6
Incorrect
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Where does protein digestion begin?
Your Answer: Mouth
Correct Answer: Stomach
Explanation:Digestion typically begins in the stomach when pepsinogen is converted to pepsin by the action of hydrochloric acid, and continued by trypsin and chymotrypsin in the small intestine.
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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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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: CT scan of the chest
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 8
Incorrect
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A cohort study is being designed to look at the relationship between smoking and prostate cancer. What is the usual outcome measure in a cohort study?
Your Answer: Experimental event rate
Correct Answer: Relative risk
Explanation:A cohort study is a particular form of longitudinal study that samples a cohort (a group of people who share a defining characteristic, typically those who experienced a common event in a selected period, such as birth or graduation), performing a cross-section at intervals through time. The relative risk (RR) or risk ratio is the ratio of the probability of an outcome in an exposed group to the probability of an outcome in an unexposed group. Relative risk is used in the statistical analysis of the data of experimental, cohort and cross-sectional studies, to estimate the strength of the association between treatments or risk factors, and outcomes.
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This question is part of the following fields:
- Medicine
- Research Skills
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Question 9
Incorrect
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The coronary sinus, which empties into the right atrium, serves to?
Your Answer: Drain the lymphatics of the heart
Correct Answer: Drain the venous supply of the myocardium
Explanation:The coronary sinus is a collection of veins joined together to form a large vessel that collects blood from the heart muscle (myocardium). It delivers deoxygenated blood to the right atrium, as do the superior and inferior vena cava.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 10
Incorrect
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The end product of trehalase action on oligosaccharides is
Your Answer: A molecule of glucose and a molecule of fructose
Correct Answer: Two glucose molecules
Explanation:Disaccharides are glycoside hydrolases, enzymes that break down certain types of sugars called disaccharides into simpler sugars called monosaccharides.Examples of disaccharides:Lactase (breaks down lactose into glucose and galactose)Maltase (breaks down maltose into 2 glucoses)Sucrase (breaks down sucrose into glucose and fructose)Trehalase (breaks down trehalose into 2 glucoses)
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 11
Incorrect
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Select the correct statement about the microanatomy of the thyroid gland.
Your Answer: The parafollicular, or c cells, have no known function.
Correct Answer: The capillaries adjacent to thyroid cells have a fenestrated endothelium.
Explanation:Fenestrated capillaries have a very thin endothelium, which is perforated by numerous fenestrations or pores. Hormones are usually released into these capillaries, reaching their target cells through the circulatory system.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 12
Incorrect
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Which of the following increase insulin secretion?
Your Answer: Phenytoin
Correct Answer: Sulfonylureas
Explanation:Sulfonylureas are a type of antidiabetic drug used to treat diabetes mellitus type 2. Their main mechanism of action is producing a rise in plasma insulin levels, through stimulation of insulin secretion and a decrease in hepatic clearance of insulin. Sulfonylureas include gliclazide, glipizide, glibenclamide and glimepiride.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 13
Correct
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Which enzyme is responsible for the conversion of testosterone to dihydrotestosterone?
Your Answer: 5α-reductase
Explanation:The enzyme 5α-reductase synthesizes DHT from testosterone in the prostate, testes, hair follicles, and adrenal glands. This enzyme reduces the 4,5 double-bond of the testosterone. Relative to testosterone, DHT is much more potent as an agonist of the androgen receptor.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 14
Incorrect
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Which of the following drugs requires plasma level monitoring?
Your Answer: Erythromycin
Correct Answer: Vancomycin
Explanation:All patients require plasma-vancomycin measurement (after 3 or 4 doses if renal function normal, earlier if renal impairment). There is a risk of nephrotoxicity including renal failure, interstitial nephritis and ototoxicity.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 15
Incorrect
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Which vitamin plays a major role in the metabolism of many amino acids?
Your Answer: Vitamin B12
Correct Answer: Vitamin B6
Explanation:Vitamin B6 is part of the vitamin B group, and its active form, pyridoxal 5′-phosphate (PLP) serves as a coenzyme in many enzyme reactions in amino acid, glucose, and lipid metabolism.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 16
Correct
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Free radicals are best defined by which of the following statements.
Your Answer: Atoms or molecules with unpaired electrons
Explanation:Free radicals form when one of weak bond between electrons is broken and an uneven number of electrons remain. This means the electron is unpaired, making it chemically reactive and attempt to steal an electron from a neighbouring molecule to stabilize itself.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 17
Correct
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Currents caused by opening of which of the following channels contribute to the repolarization phase of the action potential of the ventricular muscle fibers?
Your Answer: Potassium channels
Explanation:Depolarization occurs due to opening of the voltage gated sodium channels. Repolarization occurs due to opening of the voltage gates potassium channels causing an out flux of potassium ions, decreasing the membrane potential towards resting potential.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 18
Incorrect
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90% of erythropoietin necessary for haemopoesis is produced by the kidneys, the remainder is formed in the?
Your Answer: Lymph nodes
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 19
Incorrect
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Which of the following skin coloration abnormalities occurs due to adrenal insufficiency due to primary adrenal disease?
Your Answer: Albinism
Correct Answer: Hyperpigmentation
Explanation:Addison’s disease, also known as primary adrenal insufficiency, or hypocortisolism is an endocrine disorder. Hyperpigmentation is one of its most common signs; it occurs as a result of an increase in pro-opiomelanocortin to produce more ACTH in response to the decreased levels of cortisol. Pro-opiomelanocortin is a precursor of melanocyte stimulating hormone (MSH), which stimulates melanocytes, causing darkening of the skin.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 20
Incorrect
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Which one of the following is most likely to be seen in a patient with multiple endocrine neoplasia (MEN) type I?
Your Answer: Marfanoid body habitus
Correct Answer: Insulinoma
Explanation:Multiple endocrine neoplasia type 1 (MEN-1 syndrome) or Wermer’s syndrome is part of a group of disorders, the multiple endocrine neoplasias, that affect the endocrine system through development of neoplastic lesions in the ‘three P’s’:Parathyroid (>90%): hyperparathyroidism due to parathyroid hyperplasiaPituitary (15-42%)Pancreas (60-70%, e.g. insulinoma, gastrinoma)
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 21
Incorrect
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Regarding glomus cells, which of the following is true?
Your Answer: Have one neurotransmitter - acetylcholine.
Correct Answer: Contain catecholamines
Explanation:The carotid body detects changes in the composition of arterial blood flowing through it, mainly the partial pressure of oxygen, but also of carbon dioxide. Furthermore, it is also sensitive to changes in pH and temperature.The carotid body is made up of two types of cells, called glomus cells: Glomus type I/chief cells release a variety of neurotransmitters, including acetylcholine, ATP, and dopamine that trigger EPSPs in synapsed neurons leading to the respiratory centre.Glomus type II/sustentacular cells resemble glia, express the glial marker S100 and act as supporting cells.
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This question is part of the following fields:
- Medicine
- Respiratory
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Question 22
Correct
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Question 23
Incorrect
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A 35-year-old female has been recently diagnosed with hypertension. She's sexually active and is not using any birth control other than barrier method. Which among the following antihypertensives is contraindicated in this patient?
Your Answer: Methyldopa
Correct Answer: Lisinopril
Explanation:Among the following hypertensives, lisinopril (an ACE inhibitor) is contraindicated in patients who are planning for pregnancy.Per the NICE guidelines, when treating the woman in question, she should be treated as if she were pregnant given the absence of effective contraception. ACE inhibitors such as lisinopril are known teratogens and most be avoided.Drugs contraindicated in pregnancy:AntibioticsTetracyclinesAminoglycosidesSulphonamides and trimethoprimQuinolonesOther drugs:ACE inhibitors, angiotensin II receptor antagonistsStatinsWarfarinSulfonylureasRetinoids (including topical)Cytotoxic agentsThe majority of antiepileptics including valproate, carbamazepine, and phenytoin are known to be potentially harmful.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 24
Incorrect
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Regarding cardiac output, an increased ejection fraction results from increases in which of the following?
Your Answer: All of the above
Correct Answer: Strength of contraction without increase in muscle fiber length
Explanation:When the strength of contraction increases without an increase in fiber length, the EF increases.
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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 85 year old male with a history of Alzheimer's dementia was brought into Casualty by family members, who stated that he had episodes of aggression. Which of the following drugs is most suitable as the pharmacological management for this presentation?
Your Answer: Quetiapine
Correct Answer: Risperidone
Explanation:Regarding the pharmacological management, Risperidone is the most suitable drug from the given answers as it is recommended for the treatment of aggression associated with moderate to severe Alzheimer’s disease. Quetiapine and Benzodiazepine are not recommended.
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This question is part of the following fields:
- Geriatrics
- Medicine
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Question 26
Correct
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Three adjacent nucleotides code for a particular amino acid. These are called codons. How many common amino acids are there and how many potential codon combinations make up the genetic code?
Your Answer: 20 amino acids, 64 codon combinations
Explanation:There are around 20 amino acids and 61 out of the 64 combinations of codon code for these 20 common amino acids.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 27
Correct
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Visual pathways - Choose the true statement:
Your Answer: The lateral geniculate nucleus, magnocellular & parvocellular pathways project to the primary visual cortex
Explanation:The optic chiasm is made by the decussation of optic fibers on the nasal side. The magnocellular pathway carries signals for detection of movement. The parvocellular pathway carries cells for detection of shape, size, colour and clarity. The lateral geniculate nucleus (LGN) is the relay centre in the thalamus for he visual pathway. It has layers of magnocellular cells and parvocellular cells that are interleaved with layers of koniocellular cells. The LGN is the main central connection for the optic nerve to the occipital lobe, particularly the primary visual cortex.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 28
Correct
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Which substance has the lowest taste threshold concentration, in other words which substance can be present in the lowest concentration before taste buds will respond?
Your Answer: Strychnine hydrochloride (bitter)
Explanation:The lowest concentration of a gustatory stimulus to which the taste buds respond is considered to be the threshold concentration for that substance. The threshold concentration for strychnine is 0.0001 mm; this is because it allows the body to detect potentially dangerous substances (bitter plant components) at lower concentrations.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 29
Incorrect
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Glucose absorption in the small intestine is coupled with which of the following electrolytes?
Your Answer: Cl
Correct Answer: Na
Explanation:Sodium-glucose linked transporter are family of proteins of different types. SGLT1 transporter is found in the intestinal mucosa of the small intestine and absorbs glucose via cotransport of Na+ ions.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 30
Incorrect
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A 33-year-old electrical technician presents following an overdose. Anticholinergic syndrome is suspected. Which of the following is true?
Your Answer: Urinary incontinence is common
Correct Answer: Mydriasis occurs
Explanation:Anticholinergic syndrome occurs following overdose with drugs that have prominent anticholinergic activity including tricyclic antidepressants, antihistamines and atropine. Features include dry, warm, flushed skin, urinary retention, tachycardia, mydriasis (dilated pupils) and agitation.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 31
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 32
Incorrect
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Which is the commonest cardiovascular abnormality seen in an adult patient with Marfan’s syndrome?
Your Answer: Aortic regurgitation
Correct Answer: Aortic aneurysm
Explanation:Marfan syndrome (MFS) is a genetic disorder of connective tissue. The degree to which people are affected varies. People with Marfan’s tend to be tall, and thin, with long arms, legs, fingers and toes. They also typically have flexible joints and scoliosis. The most serious complications involve the heart and aorta with an increased risk of mitral valve prolapse and aortic aneurysm.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 33
Incorrect
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Which of the following cells secrete glucagon?
Your Answer: G cells
Correct Answer: A cells
Explanation:Glucagon counteracts hypoglycaemia and opposes insulin by promoting gluconeogenesis and glycogenolysis. It also decreases fatty acid synthesis in the liver and adipose tissue, and promotes lipolysis. It is secreted by the pancreatic islet α-cells. Its production is regulated by the insulin produced in β-cells.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 34
Incorrect
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A 35-year-old male presented to the ER after being rescued from a house fire. He complained of feeling dizzy and having a worsening headache. On examination, he was dyspnoeic, drowsy and confused. There was no evidence of facial burns and no stridor. He was normotensive, tachycardic (pulse rate: 102 bpm), tachypnoeic (respiratory rate: 35/min) and had O2 saturation of 100% in room air. His venous blood gas results are given below: pH - 7.28pCO2 - 3.5 kPapO2 - 15.9 kPaNa+ - 139 mmol/LK+ - 4.5 mmol/LBicarbonate - 11 mmol/LChloride - 113 mmol/LLactate - 13.6 mmol/LKeeping in mind the likely diagnosis, which among the following is the most appropriate intervention for this patient?
Your Answer: Intravenous dexamethasone
Correct Answer: Intravenous hydroxocobalamin
Explanation:The most appropriate intervention in this patient is intravenous hydroxocobalamin.The clinical scenario provided is suggestive of acute cyanide toxicity secondary to burning plastics in the house fire. Cyanide ions inhibit mitochondrial cytochrome oxidase, preventing aerobic respiration. This manifests in normal oxygen saturations, a high pO2 and flushing (or ‘brick red’ skin) brought on by the excess oxygenation of venous blood. In the question above it is important to note that the blood gas sample given is venous rather than arterial. His blood gas also demonstrates an increased anion gap, consistent with his high lactate (generated by anaerobic respiration due to the inability to use available oxygen).The recommended treatment for moderate cyanide toxicity in the UK is one of three options: sodium thiosulfate, hydroxocobalamin or dicobalt edetate. Among the options given is hydroxocobalamin and this is, therefore, the correct answer. Hydroxocobalamin additionally has the best side-effect profile and speed of onset compared with other treatments for cyanide poisoning.Other options:- Intubation would be appropriate treatment in the context of airway burns but this patient has no evidence of these, although close monitoring would be advised. – High-flow oxygen is the treatment for carbon monoxide poisoning – a sensible differential, but this man’s very high lactate and high venous pO2 fit better with cyanide toxicity. Intravenous dexamethasone would be another treatment for airway oedema once an endotracheal tube had been placed. – Intravenous sodium nitroprusside is a treatment for high blood pressure that can cause cyanide poisoning, and would, therefore, be inappropriate.Note:Cyanide may be used in insecticides, photograph development and the production of certain metals. Toxicity results from reversible inhibition of cellular oxidizing enzymesClinical presentation:Classical features: brick-red skin, the smell of bitter almondsAcute: hypoxia, hypotension, headache, confusionChronic: ataxia, peripheral neuropathy, dermatitisManagement:Supportive measures: 100% oxygenDefinitive: hydroxocobalamin (intravenously), also a combination of amyl nitrite (inhaled), sodium nitrite (intravenously), and sodium thiosulfate (intravenously).
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 35
Incorrect
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The premotor cortex is:
Your Answer: Brodmann area 8
Correct Answer: Brodmann area 6
Explanation:A Brodmann area in the brain is defined by cytoarchitecture, histology and organization of cells:Primary Sensory 3,1,2Primary Motor 4Premotor 6Primary Visual 17Primary Auditory 41Brocas 44
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This question is part of the following fields:
- Medicine
- Neurology
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Question 36
Incorrect
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Using the Cockcroft-Gault formula, what will the estimated creatinine clearance be of a 55 year old male who weighs 75kg and has a serum creatinine of 150mg/dL?
Your Answer: 0.22ml/min
Correct Answer: 0.59ml/min
Explanation:A commonly used surrogate marker for estimate of creatinine clearance is the Cockcroft-Gault (CG) formula, which in turn estimates GFR in ml/min:CCr = [(140-age) x Mass(kg)]/[72 x serum creatinine (mg/dL)](multiply by 0.85 for women)Therefore CCr = (85 x 75)/(72 x 150) = 0.59
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This question is part of the following fields:
- Medicine
- Renal
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Question 37
Incorrect
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Which of the following features do mast cells and basophils have in common:
Your Answer: Both degranulate in response to histamine release
Correct Answer: Are essential for immediate type-hypersensitivity reactions
Explanation:Anaphylaxis is a severe immediate allergic reaction of rapid onset affecting many body systems. It is due to the release of inflammatory mediators and cytokines from mast cells and basophils. Basophils are the least common of the granulocytes, representing about 0.5 to 1% of circulating white blood cells. However, they are the largest type of granulocyte. They are responsible for inflammatory reactions during immune response, as well as in the formation of acute and chronic allergic diseases, including anaphylaxis, asthma, atopic dermatitis and hay fever. They can perform phagocytosis (cell eating), produce histamine and serotonin that induce inflammation, and heparin that prevents blood clotting. Mast cells are similar in appearance and function. Both cell types store histamine, a chemical that is secreted by the cells when stimulated.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 38
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: Minimal change nephropathy
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 39
Incorrect
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The interior of lysosomes is kept at a pH of around 5 by the action of:
Your Answer: Na/H exchanger
Correct Answer: H+ ATPase
Explanation:The lysosome maintains its pH differential by pumping in protons (H+ ions) from the cytosol across the membrane via proton pumps and chloride ion channels. Vacuolar H+-ATPases are responsible for transport of protons, while the counter transport of chloride ions is performed by ClC-7 Cl−/H+ antiporter.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 40
Incorrect
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Arachidonic acid is converted to:
Your Answer: Prostaglandin G/H synthases
Correct Answer: Prostaglandin H2
Explanation:The enzymes cyclooxygenase-1 and -2 (i.e. prostaglandin G/H synthase 1 and 2 {PTGS1 and PTGS2}) metabolize arachidonic acid to Prostaglandin G2 and prostaglandin H2.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 41
Incorrect
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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 42
Incorrect
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A 24-year-old women presents following an overdose. Which one of the following would suggest anticholinergic syndrome?
Your Answer: Tricyclic antidepressants are not a cause
Correct Answer: Mydriasis occurs
Explanation:Anticholinergic syndrome results from the inhibition of muscarinic cholinergic neurotransmission. Clinical manifestations can be remembered by the mnemonic, red as a beet, dry as a bone, blind as a bat, mad as a hatter, hot as a hare, and full as a flask. The mnemonic refers to the symptoms of flushing, dry skin and mucous membranes, mydriasis (dilated pupil) with loss of accommodation, altered mental status, fever, and urinary retention, respectively.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 43
Incorrect
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Choose the standard method for comparing distributions in data sets (such as between the expected frequency of an event and the observed frequency of an event) from the list of options.
Your Answer: Median
Correct Answer: Chi squared (X²) test
Explanation:The Chi-squared test evaluates if two variables are related. The other statistical tests mentioned do not perform this function.
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This question is part of the following fields:
- Medicine
- Research Skills
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Question 44
Incorrect
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Where does secretin work in the pancreas?
Your Answer: Zymogen granules
Correct Answer: Pancreatic ducts
Explanation:Secretin, a hormone produced by the duodenal S cells in response to the stomach chyme containing high hydrogen atom concentration (high acidity), is released into the blood stream; upon return to the digestive tract, secretion decreases gastric emptying, increases secretion of the pancreatic ductal cells, as well as stimulating pancreatic acinar cells to release their zymogenic juice.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 45
Incorrect
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A 26-year-old student has been brought to the emergency department in a confused state. His friends report that he has been complaining of headaches for the past few weeks. He has a low-grade fever and on examination is noted to have abnormally pink mucosa. What is the most likely diagnosis?
Your Answer: Methemoglobinemia
Correct Answer: Carbon monoxide poisoning
Explanation:Confusion and pink mucosae are typical features of CO poisoning.The patient often presents, most commonly with headaches, and other symptoms like malaise, nausea, and dizziness.Carbon monoxide (CO) poisoning, considered as the great imitator of other diseases as the patients present with a myriad of symptoms. The carbon monoxide diffuses rapidly across the pulmonary capillary membrane binding to the haem molecule with a very high affinity (240 times that of oxygen) forming carboxy-haemoglobin (COHb). Non-smokers have a baseline COHb of ,3% while smokers have a baseline COHb of 10-15%.Features of carbon monoxide toxicity- Headache: 90% of cases- Nausea and vomiting: 50%- Vertigo: 50%- Confusion: 30%- Subjective weakness: 20%- Severe toxicity: ‘pink’ skin and mucosae, hyperpyrexia, arrhythmias, extrapyramidal features, coma, deathTreatment:Use of Hyperbaric oxygen therapy (HBOT) for treating mild to moderate CO poisoning is not routine.The selection criteria for HBOT in cases of CO poisoning include:• COHb levels > 20-25%• COHb levels > 20% in pregnant patient • Loss of consciousness• Severe metabolic acidosis (pH <7.1)• Evidence of end-organ ischemia (e.g., ECG changes, chest pain, or altered mental status)
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 46
Incorrect
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Select the correct pairing regarding the surface of the cerebral hemispheres.
Your Answer: Temporal lobe : primary motor and premotor cortices
Correct Answer: Parietal lobe : primary somatosensory cortex
Explanation:Parietal lobe: The primary somatosensory cortex is located in the postcentral gyrus of the parietal lobe. It is responsible for processing sensory information from the body.
Frontal lobe: The primary motor cortex is located in the precentral gyrus of the frontal lobe. The frontal lobe also contains the premotor cortex, which is involved in planning movements. The primary visual cortex is located in the occipital lobe, not the frontal lobe.
Temporal lobe: The primary auditory cortex is located in the superior temporal gyrus of the temporal lobe. The primary motor and premotor cortices are located in the frontal lobe, not the temporal lobe.
Occipital lobe: The primary visual cortex is located in the occipital lobe. The primary auditory cortex is located in the temporal lobe, not the occipital lobe.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 47
Correct
-
During which phase are the 2 chromatids pulled apart at the centromere?
Your Answer: Anaphase
Explanation:During the prometaphase the microtubule organizing centre completely develops. The spindle fibers attach to the chromosome and the centriole. It is in the Anaphase however that the spindle fibers contract pulling the sister chromatids apart. Later in the anaphase a cleave furrow beings to forms.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 48
Incorrect
-
A 32 year old man presents with blistering and hyperpigmentation on his face and hands, after a beach holiday with friends. Tests reveal high levels of uroporphyrinogen in the urine. The most likely diagnosis is:
Your Answer: Systemic lupus erythematosus
Correct Answer: Porphyria cutanea tarda
Explanation:Porphyria cutanea tarda (PCT) is the most common of the porphyries. It is characterised by fragility and blistering of exposed skin. Typically, patients who are ultimately diagnosed with PCT first seek treatment following the development photosensitivities in the form of blisters and erosions on commonly exposed areas of the skin. This is usually observed in the face, hands, forearms, and lower legs. It heals slowly and with scarring. Though blisters are the most common skin manifestations of PCT, other skin manifestations like hyperpigmentation (as if they are getting a tan) and hypertrichosis (mainly on top of the cheeks) also occur. Risk factors for the development of PCT include alcohol and sun.
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This question is part of the following fields:
- Dermatology
- Medicine
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Question 49
Incorrect
-
Which of the following are responsible for the 4th heart sound?
Your Answer: Closure of the atrio-ventricular valves
Correct Answer: Ventricular hypertrophy
Explanation:The fourth heart sound is not normally audible in a normal adult. It occurs as a consequence of ventricular hypertrophy. It is caused by filling of the ventricle in atrial systole.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 50
Incorrect
-
Critical shortening of Telomeres result in:
Your Answer: Activation of DNA polymerase
Correct Answer: Activation of p53 and prb and cell crisis
Explanation:Telomeres are repetitive nucleotide sequences at the ends of chromosomes that protect them from deterioration or from fusion with neighboring chromosomes. Each time a cell divides, its telomeres shorten. When they become critically short, they can no longer protect the chromosome ends, triggering a DNA damage response.
This response leads to the activation of tumor suppressor proteins p53 and pRb (retinoblastoma protein). Activated p53 can induce cell cycle arrest, allowing time for DNA repair or triggering apoptosis if the damage is irreparable. Similarly, pRb helps regulate cell cycle progression and can halt the cell cycle to prevent the proliferation of cells with damaged DNA.
As a result, the cell enters a state of crisis, characterized by widespread cell death and genomic instability, which ultimately prevents the propagation of cells with critically shortened telomeres.
Therefore, the correct answer is:
Activation of p53 and pRb and cell crisis
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This question is part of the following fields:
- Genetics
- Medicine
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Question 51
Correct
-
The Sinoatrial node in the majority of people is supplied by the?
Your Answer: Right coronary artery
Explanation:In 60% of people, the SA node is supplied by the right coronary artery branch and in 40% of the people by the left coronary artery.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 52
Incorrect
-
A 64 year old woman who is of Asian descent and is diabetic (controlled by diet) presents with generalized body aches and difficulty rising from sitting for the last few months. Her blood glucose levels are in the normal range. Lab examination reveals normal blood cell count, low serum phosphate, calcium at the lower range, and raised alkaline phosphatase levels. Radiological examination shows which of the following?
Your Answer: Brodie’s abscess
Correct Answer: Linear areas of low density
Explanation:Osteomalacia is a condition due to defective mineralization of osteoid. Occurs as a result of Vitamin D deficiency secondary to poor dietary intake and sun exposure, malabsorption e.g., inflammatory bowel disease and gastrointestinal bypass surgery. Radiological findings include reduced bone mineral density (a non specific finding), inability to radiologically distinguish vertebral body trabeculae (the film appears poor quality), looser pseudo fractures, fissures, or narrow radiolucent lines (these are the characteristic findings). Osteolytic or punched out lesions may be seen with multiple myeloma and bony metastases. Areas of sclerosis may be observed with conditions like osteosclerosis and Paget disease. A Brodie abscess is a subacute osteomyelitis, which may persist for years before progressing to a chronic, frank osteomyelitis.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 53
Incorrect
-
On a mountain the atmospheric pressure is 700 mmHg and the humidity close to zero, the partial pressure of oxygen is:
Your Answer: 110 mmHg
Correct Answer: 147 mmHg
Explanation:Natural air includes approximately 21% of oxygen. If humidity is zero, the partial pressure of oxygen is 700 × 21% = 147 mmHg
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This question is part of the following fields:
- Medicine
- Respiratory
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Question 54
Incorrect
-
Peristalsis is an example of:
Your Answer: None of the options
Correct Answer: Enteric nervous system
Explanation:Peristalsis is a type of contraction where radial symmetrical contraction and relaxation of muscles propagates food in a downward wave through the gut. The enteric nervous system is one of the main divisions of the nervous system and consists of a mesh-like system of neurons that controls the function of the gastrointestinal tract. It has an independent reflex activity. The neurons of this system re collected into two types of ganglia: myenteric (or Auerbach’s) and submucosal (or Meissner’s plexuses). Myenteric plexuses are located between the inner and outer layers of the muscularis externa, while submucosal plexuses are located in the submucosa.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 55
Incorrect
-
Which of the following causes an increase in venous return?
Your Answer: Peripheral vasodilatation
Correct Answer: An increase in the negative intra-thoracic pressure
Explanation:During inspiration, intrathoracic pressure becomes more negative and intra-abdominal pressure more positive. This increases the venous pressure gradient from abdomen to thorax and promotes filling of the central veins.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 56
Incorrect
-
VIP, GIP and somatostatin play an inhibitory role in gastric acid secretion by inactivating?
Your Answer: Enterochromatin like cells
Correct Answer: G cells
Explanation:Gastrin is secreted from the G cells. VIP, GIP and somatostatin all inhibit acid production by inhibiting the G cells.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 57
Correct
-
In Argyll Robertson pupils…
Your Answer: All of the options given
Explanation:Argyll Robertson pupils are bilaterally small pupils that accommodate or reduce in size near an object but do not react to light. They do not constrict when exposed to bright light. They are a highly specific sign of neurosyphilis but may be seen in diabetic neuropathy as well.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 58
Incorrect
-
One of the functions of the spleen with regards to red blood cells is:
Your Answer: To replenish the body with pluripotent stem cells
Correct Answer: To filter and remove aged and abnormal red blood cells
Explanation:The spleen plays important roles in regard to red blood cells (also referred to as erythrocytes) and the immune system. It removes old red blood cells and holds a reserve of blood, which can be valuable in case of haemorrhagic shock, and also recycles iron. As a part of the mononuclear phagocyte system, it metabolizes haemoglobin removed from senescent erythrocytes. The globin portion of haemoglobin is degraded to its constitutive amino acids, and the haem portion is metabolized to bilirubin, which is removed in the liver.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 59
Incorrect
-
The superior orbital fissure is the site of entry/exit for which of the following group of nerves?
Your Answer: CN III, IV, V3, VI
Correct Answer: CN III, IV, V1, VI
Explanation:The superior and inferior divisions of oculomotor nerve (III), trochlear nerve (IV), lacrimal, frontal and nasociliary branches of ophthalmic V1 and the abducens nerve (VI)
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This question is part of the following fields:
- Medicine
- Neurology
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Question 60
Incorrect
-
Where is Vitamin B 12 absorbed?
Your Answer: Duodenum
Correct Answer: Terminal ileum
Explanation:Protein-bound vitamin B12 must be released from the proteins by the action of digestive proteases in both the stomach and small intestine. Gastric acid releases the vitamin from food particles; therefore antacid and acid-blocking medications (especially proton-pump inhibitors) may inhibit absorption of B12. B12 must be attached to Intrinsic Factor (IF) for it to be efficiently absorbed, as receptors on the enterocytes in the terminal ileum of the small bowel only recognize the B12-IF complex; in addition, intrinsic factor protects the vitamin from catabolism by intestinal bacteria.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 61
Incorrect
-
Which of the following are true with regard to autosomal recessive disorders:
Your Answer: The parents of the affected offspring are generally unaffected healthy carriers
Correct Answer: All are true
Explanation:All are true for autosomal recessive disorders.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 62
Correct
-
Regarding restriction fragment length polymorphisms (RFLP) and Gene Knockout Mouse Models. All are true except:
Your Answer: In knockout mouse models a gene is turned on through targeted mutation
Explanation:In RFLP, polymorphism occurs in 98% of the non coding genome, resulting in no phenotypical change in the organism. A gene is not turned on by a mutation, rather the mutation at the restriction site will alter the DNA and the DNA will now form fragments of different lengths. PCR is a better technique than RFLP.
A knockout, as related to genomics, refers to the use of genetic engineering to inactivate or remove one or more specific genes from an organism. Scientists create knockout organisms to study the impact of removing a gene from an organism, which often allows them to then learn something about that gene’s function.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 63
Incorrect
-
In which stage of mitosis are the chromosomes most obvious or prominent?
Your Answer: Telophase
Correct Answer: Metaphase
Explanation:Prophase begins when the nucleus envelope disintegrates and the chromosomes start to condense. The chromosomes consist of two sister chromatids that are joined at a constriction known as centromere. When the cell reaches the metaphase the chromosomes are completely condensed and ready to align on the equatorial plate.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 64
Correct
-
Which one of the following interventions has the least role in management of acne rosacea?
Your Answer: Low-dose topical corticosteroids
Explanation:Mild cases are often not treated at all, or are simply covered up with normal cosmetics and avoiding sun exposure. Therapy for the treatment of rosacea is not curative, and is best measured in terms of reduction in the amount of facial redness and inflammatory lesions. The two primary modalities of rosacea treatment are topical and oral antibiotic agents (including metronidazole and tetracyclines). Laser therapy may be appropriate for patients with prominent telangiectasia.
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This question is part of the following fields:
- Dermatology
- Medicine
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Question 65
Correct
-
Nucleic acids are split into nucleotides in the:
Your Answer: Intestine
Explanation:The pancreas is the major source for all the digestive enzymes including nucleases which split nucleic acids into nucleotides primarily in the small intestine.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 66
Incorrect
-
An 80-year-old woman with advanced COPD has been admitted to the medicine ward in an unconscious state. She appears to have an acute lower respiratory tract infection. After consulting with an anaesthesiologist it was concluded that she was not a candidate for intensive care unit admission and thus, a decision was made to start the patient on doxapram therapy. Which of the following best fits the characteristics of doxapram?
Your Answer: It is compatible in infusion with aminophylline
Correct Answer: It is contraindicated in hyperthyroidism
Explanation:The two statements that fit the characteristics of doxapram are, epilepsy is a contraindication for doxapram use and concurrent use with theophylline may increase agitation.Doxapram is a central respiratory stimulant. In clinical practice, doxapram is usually used for patients who have an acute exacerbation of chronic obstructive pulmonary disease (COPD) who are unsuitable for admission to the intensive therapy unit for ventilatory support. Doxapram infusion may buy an extra 24 h to allow for recovery.Contraindications include: ischaemic heart disease, epilepsy, cerebral oedema, acute stroke, asthma, hypertension, hyperthyroidism, and pheochromocytoma. The infusion may worsen agitation and dyspnoea and lead to hypertension, nausea, vomiting and urinary retention.Drug interactions:Concomitant administration of doxapram and aminophylline (theophylline) can cause increased skeletal muscle activity, agitation, and hyperactivity.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 67
Correct
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Question 68
Incorrect
-
What is the function of basic electrical rhythm
Your Answer: Segmentation and mixing
Correct Answer: To coordinate peristalsis and other motor activity
Explanation:The basal or basic electrical rhythm (BER) or electrical control activity (ECA) determines the frequency of the contractions in the gastrointestinal (GI) tract, thus acting to coordinate peristalsis.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 69
Incorrect
-
Which vitamin is found in NAD and NADP?
Your Answer: Vitamin B1
Correct Answer: Vitamin B3
Explanation:In organisms, NAD can be synthesized from simple building-blocks (de novo) from the amino acids tryptophan or aspartic acid. In an alternative fashion, more complex components of the coenzymes are taken up from food as the vitamin called niacin (vitamin B3)
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This question is part of the following fields:
- Haematology
- Medicine
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Question 70
Incorrect
-
Physiological effects of T3 on the heart include all the following except:
Your Answer: Enhanced response to circulating catecholamines
Correct Answer: Increased expression of β-myosin heavy chain gene
Explanation:Tri-iodothyronine, also known as T3, is a hormone which can affect almost every system in the human body. In the heart, it increases the number of β1-adrenergic receptors, enhances the response to circulating catecholamines, increases the proportion of α-myosin heavy chains in the atria, and increases the expression of serca pump gene.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 71
Incorrect
-
Which among the following antihypertensives is centrally acting?
Your Answer: Phenoxybenzamine
Correct Answer: Moxonidine
Explanation:Moxonidine and alpha-methyl dopa are centrally acting antihypertensives and modify blood pressure through modifying sympathetic activity.Other options:Verapamil is a calcium antagonist.Minoxidil and hydralazine are both vasodilators.Phenoxybenzamine is an alpha-blocker.Adverse effects:Dry mouth and somnolence were the most frequently reported adverse events, followed by headache, dizziness, nausea and allergic skin reactions.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 72
Correct
-
Where does one find the thyroid receptors?
Your Answer: Cell nucleus
Explanation:Unlike many of the steroid receptors, inactive receptors for T3 are located in the nucleus. T4 is first converted into T3 within the cytoplasm of the cell, T3 then enters the nucleus and binds to its receptor. The hormone-receptor complex can now bind to DNA and activate specific genes.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 73
Incorrect
-
A 16 year old previously well male presents with a 4 day history of fever, lethargy and a generalized macular rash. There is no significant previous medical history and the patient has not travelled abroad either. Vitals are as follows: Temp: 38.5BP: 125/75mmHgPulse: 100/min On auscultation the chest was clear and no heart murmur was heard. Examination also reveals a non blanching widespread macular rash over the chest and abdomen. There is swelling of interphalangeal joints of both hands and feet associated with mild tenderness. Lymph nodes are palpable over the supraclavicular, axillary and inguinal areas. Abdominal examination reveals palpable mass on both right and left hypochondrium. Lab results are given below:Haemoglobin (Hb) 13.5 g/dlWhite cell count (WCC) 14.0 × 109/lPlatelets 380 × 109/lSodium 145 mmol/lPotassium 4.8 mmol/lCreatinine 89 μmol/lRheumatoid factor NegativeAntinuclear antibody NegativeAnti-dsDNA NegativeASO titre Not detectedElectrocardiogram (ECG) Sinus rhythmWhat is the most likely underlying diagnosis?
Your Answer: Juvenile systemic lupus erythematosus
Correct Answer: Systemic Still’s disease
Explanation:People with Systemic Juvenile Idiopathic Arthritis (also known as Stills disease) can have recurrent fevers, a macular rash, joint pain, joint deformities, an enlarged liver and/or spleen, and can occasionally have polyserositis, lung involvement or pericardial effusions. Rheumatoid factor and antinuclear antibodies are usually negative. Treatment is with non-steroidal anti-inflammatory drugs (NSAIDs) and the prognosis is better than for adult rheumatoid arthritis.In pauciarticular Still’s disease, antinuclear antibodies are present. Large joints are affected and most patients develop classic features of seronegative spondylarthritis.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 74
Incorrect
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Question 75
Incorrect
-
Antibiotic resistance may happen by:
Your Answer: By transduction when naked DNA is incorporated by the host DNA
Correct Answer: By enzymes which inactivate the drug
Explanation:The three main mechanisms of antibiotic resistance are, enzymatic degradation of antibacterial drugs, alteration of bacterial proteins that are antimicrobial targets, and changes in membrane permeability to antibiotics.
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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Question 76
Correct
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Question 77
Incorrect
-
An exaggerated response to a noxious stimulus is called:
Your Answer: Menthol-sensitive receptor pain
Correct 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 78
Correct
-
A 53-year-old female teacher asks about hormone replacement therapy (HRT). What is the most compelling indication for starting HRT?
Your Answer: Control of vasomotor symptoms such as flushing
Explanation:Hormone replacement therapy (HRT) involves the use of a small dose of oestrogen, combined with a progestogen (in women with a uterus), to help alleviate menopausal symptoms. The main indication is the control of vasomotor symptoms. The other indications, such as reversal of vaginal atrophy and prevention of osteoporosis, should be treated with other agents as first-line therapies.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 79
Incorrect
-
Carotid bodies...
Your Answer: Are found only on the right side
Correct 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 80
Incorrect
-
Which pair is correct concerning enteroendocrine cells in the GIT mucosa and their products?
Your Answer: Enterochromaffin cells and VIP
Correct Answer: D cells and somatostatin
Explanation:Somatostatin, an inhibitory hormone is secreted form the D cells of the Pancreatic Islets.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 81
Correct
-
Which of the following is NOT associated with the development of aortic regurgitation?
Your Answer: Dilated cardiomyopathy
Explanation:Aortic insufficiency, is often due to the aortic root dilation, which is idiopathic in over 80% of cases, but otherwise may result from aging, syphilitic aortitis, osteogenesis imperfecta, aortic dissection, Bechet’s disease, reactive arthritis and systemic hypertension. Additionally, aortic insufficiency has been linked to the use of some medications and other potential causes that affect the valve directly including Marfan’s syndrome, Ehlers–Danlos syndrome, ankylosing spondylitis, and systemic lupus erythematosus. In acute cases of aortic insufficiency, the main causes are infective endocarditis, aortic dissection or trauma. Dilated cardiomyopathy is associated with the development of mitral regurgitation, not aortic regurgitation
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 82
Correct
-
A 50-year-old farmer, under treatment for depression, presents to the emergency department following an intentional overdose of an unidentified substance. On examination, he was found to be bradycardic, hypotensive, hyper-salivating, and disoriented. On ocular examination, his pupils were found to be miotic. What is the most likely substance he ingested?
Your Answer: An organophosphate insecticide
Explanation:The farmer has most likely ingested an organophosphate insecticide.Organophosphorus compounds are used widely as:• Insecticides – Malathion, parathion, diazinon, dichlorvos• Nerve gases – Soman, sarin, tabun, VX• Ophthalmic agents – Echothiophate• Antihelmintics – Trichlorfon• Herbicides – merphos• Industrial chemical (plasticizer) – Tricresyl phosphateSigns and symptoms of Organophosphorus Poisoning (OPP) can be classified as:• Muscarinic effects:o Cardiovascular – Bradycardia, hypotensiono Respiratory – Rhinorrhoea, bronchorrhea, bronchospasm, cough, severe respiratory distresso Gastrointestinal – Hypersalivation, nausea and vomiting, abdominal pain, diarrhoea, faecal incontinenceo Genitourinary – Incontinenceo Ocular – Blurred vision, miosiso Glands – Increased lacrimation, diaphoresis• Nicotinic effects:o Muscle fasciculation, weakness, cramping, diaphragmatic failure, and autonomic side effects include: hypertension, tachycardia, and mydriasis.• Central nervous system (CNS) effects:o Anxiety, emotional lability, restlessness, confusion, ataxia, tremors, seizures, coma, apnoeaMainstay Treatment:• Decontamination• Securing Airway, Breathing and Circulation• Atropine• Pralidoxime• Benzodiazepines
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 83
Correct
-
Which of the following would be a contraindication to thrombolysis?
Your Answer: Intracranial neoplasm
Explanation:Absolute contraindications to thrombolysis include:
- Previous intracranial bleeding at any time
- Stroke in less than 6 months
- Closed head or facial trauma within 3 months
- Suspected aortic dissection
- Ischemic stroke within 3 months (except in ischemic stroke within 3 hours time)
- Active bleeding diathesis
- Uncontrolled high blood pressure (>180 systolic or >100 diastolic)
- Known structural cerebral vascular lesion
- Arterio-venous malformations
- Thrombocytopenia
- Known coagulation disorders
- Aneurysm
- Brain tumours
- Pericardial effusion
- Septic embolus
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 84
Incorrect
-
The ability of the SA node cells to allow ionic flow through channels activated in a hyperpolarized state is known as:
Your Answer: All of the above
Correct Answer: Pace maker potential
Explanation:Rhythmically discharging cells have a membrane potential that, after each impulse, declines to the firing level. Thus this prepotential or Pacemaker potential triggers the next impulse. The inherent leakiness of the sinus nodal fibers to Na+ and Ca2+ causes their self excitation.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 85
Incorrect
-
Where is thyroglobulin produced?
Your Answer: Posterior pituitary
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 86
Incorrect
-
The residual cleft of the intermediate lobe of the pituitary is lined by follicles resembling which human gland?
Your Answer: Adrenal medulla
Correct Answer: Thyroid
Explanation:The cells located between the two main pituitary lobes form what is known as the intermediate pituitary. This area secretes melanocyte-stimulating hormone and it is only a few cell layers thick. It is rich in follicles filled with colloid, and lined by basophilic cells. This configuration resembles that of another important gland: the thyroid.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 87
Incorrect
-
Which inhibitor of gastric enzyme secretion is released by the presence of fat in the jejunum?
Your Answer: Glucagon
Correct Answer: Peptide yy
Explanation:Peptide yy is secreted from the jejunum due to the presence of fat. It inhibits gastric acid secretion and motility.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 88
Incorrect
-
The immunoglobulin found in the highest concentration in humans is
Your Answer: IgD
Correct Answer: IgG
Explanation:Representing approximately 75% of serum antibodies in humans, IgG is the most common type of antibody found in the circulation. IgG molecules are created and released by plasma B cells.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 89
Incorrect
-
An 18 year old girl presents with short history of marked, right hip pain and an associated limp. She has a history of acute lymphoblastic leukaemia for which she completed treatment for last six months.
Your Answer: Gout
Correct Answer: Avascular necrosis of the femoral head
Explanation:Avascular necrosis (AVN) of the femoral head is a pathological process that results from disruption of the blood supply to the bone and occurs most commonly in the femoral epiphysis. Patients usually present with pain and limited joint motion. The mechanism involves impaired circulation to a specific area that ultimately becomes necrotic. AVN is most frequently associated with high doses of oral and intravenous corticosteroids and prolonged duration of therapy. Cancer patients receiving chemotherapy are usually also treated with corticosteroids.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 90
Incorrect
-
Cyclic AMP activates the following enzyme
Your Answer: Phosphodiesterase
Correct Answer: Protein Kinase A
Explanation:Cyclic AMP works by activating protein kinase A (PKA, or cAMP-dependent protein kinase). Protein kinase A can also phosphorylate specific proteins that bind to promoter regions of DNA, causing increases in transcription.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 91
Correct
-
Telomerase is active in the following cells except:
Your Answer: Certain osteoblasts
Explanation:Some cells have the ability to reverse telomere shortening by expressing telomerase, an enzyme that extends the telomeres of chromosomes. Telomerase is an RNA-dependent DNA polymerase, meaning an enzyme that can make DNA using RNA as a template.
Telomerase is not usually active in most somatic cells (cells of the body), but it’s active in germ cells (the cells that make sperm and eggs) and some adult stem cells. These are cell types that need to undergo many divisions, or, in the case of germ cells, give rise to a new organism with its telomeric “clock” reset.Interestingly, many cancer cells have shortened telomeres, and telomerase is active in these cells. If telomerase could be inhibited by drugs as part of cancer therapy, their excess division (and thus, the growth of the cancerous tumor) could potentially be stopped.A subset of liver cells with high levels of telomerase renews the organ during normal cell turnover and after injury. -
This question is part of the following fields:
- Genetics
- Medicine
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Question 92
Incorrect
-
The function of Troponin T in cardiac muscle is?
Your Answer: Inhibition of interaction between myosin and actin
Correct Answer: Allows attachment of troponin components to tropomyosin
Explanation:Troponin T binds the troponin components to tropomyosin. Troponin I inhibits the interaction of myosin with actin, and troponin C contains the binding sites for the Ca2+ that helps initiate contraction.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 93
Incorrect
-
Which of the following is true regarding platelets?
Your Answer: They are nucleated
Correct Answer: Normally have a half-life of about 8 days
Explanation:Platelets have no cell nucleus: they are fragments of cytoplasm that are derived from the megakaryocytes of the bone marrow, and then enter the circulation. They have a half life of 5-9 days.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 94
Incorrect
-
Which statement is incorrect?
Your Answer: Poly a tail is not translated and is preceded by a stop codon, UAA, UAG, UGA.
Correct Answer: Translation begins when the triplet (UGA) encoding for methionine is encountered.
Explanation:Translation being when the codon for methionine is encountered which is AUG not UGA. This process is known as initiation. All the other options are correct.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 95
Correct
-
Where is the lower border of the liver usually found?
Your Answer: 10th rib anterior axillary line on right
Explanation:Assessment of liver margins is important clinically to determine the size of the liver and is done via percussion during the physical examination. The liver typically extends from the fifth intercostal space or 6th rib to the right costal margin in the midclavicular line and the 10th rib on anterior axillary line.
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This question is part of the following fields:
- Hepatobiliary
- Medicine
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Question 96
Correct
-
What is the primary problem of achalasia
Your Answer: Deficiency of myenteric plexus at the lower oesophageal sphincter
Explanation:Oesophageal achalasia is an oesophageal motility disorder involving the smooth muscle layer of the oesophagus is characterized by the failure of the lower oesophageal sphincter (LES) relaxation and aperistalsis, caused primarily by the loss of the inhibitory innervation of the oesophageal myenteric plexus.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 97
Incorrect
-
Almost all of the protein that appears in the stool is:
Your Answer: From digestive juices
Correct Answer: Comes from bacteria and cellular debris
Explanation:75% of faecal weight is water. By dry weight 30% of faeces is bacteria,10-20% is fat and 2-3% proteins. Almost all proteins ingested are absorbed in the gut.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 98
Incorrect
-
Which is NOT a prognostic factor for patients with malignant melanoma?
Your Answer: Surface ulceration
Correct Answer: Diameter of melanoma > 6 mm
Explanation:Features that affect prognosis are tumour thickness in millimetres (Breslow’s depth – the deeper the Breslow thickness the poorer the prognosis.), depth related to skin structures (Clark level – the level of invasion through the dermis), type of melanoma, presence of ulceration, presence of lymphatic/perineural invasion, presence of tumour-infiltrating lymphocytes (if present, prognosis is better), location of lesion, presence of satellite lesions, and presence of regional or distant metastasis. Malignant melanoma tends to grow radially before entering a vertical growth phase. The diameter it reaches has not been found to be a prognostic factor.
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This question is part of the following fields:
- Dermatology
- Medicine
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Question 99
Incorrect
-
Which of the following has the shortest duration:
Your Answer: Atrial diastole
Correct Answer: Atrial systole
Explanation:Atrial systole: 0.1s
Atrial diastole: around 0.4s
Ventricular diastole: 0.4-0.53s
Ventricular systole: 0.27s
PR interval: 0.12-0.2 s
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 100
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 101
Correct
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Question 102
Incorrect
-
With regards to the deiodinases, where would you find D1?
Your Answer: Pituitary gland
Correct Answer: Liver
Explanation:The liver produces an important amount of T3 by outer ring deiodination thanks to its elevated concentration of type I deiodinase. It can also be found in the kidney.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 103
Incorrect
-
Tumour necrosis factor is a cytokine. What is its major function?
Your Answer: Immunosuppression
Correct 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 104
Incorrect
-
What is the most appropriate management of a DVT during pregnancy?
Your Answer: Aspirin
Correct Answer: Heparin
Explanation:Low molecular weight heparin (LMWH) is safe in pregnancy and is therefore the first line management. Warfarin is teratogenic and must be avoided whilst the other options have no role to play.
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This question is part of the following fields:
- Medicine
- Respiratory
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Question 105
Correct
-
On which chromosome is the gene for insulin located?
Your Answer: Chromosome 11
Explanation:Humans have 23 pairs of chromosomes, and usually, two pairs of copies of chromosome 11. It is one of the most complex, gene-rich chromosomes in the human genome, and it is associated with a number of diseases. Studies have shown they the human insulin gene is located on the short arm of chromosome 11.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 106
Incorrect
-
In which organelle is the intrinsic apoptotic pathway initiated?
Your Answer: Peroxisome
Correct Answer: Mitochondria
Explanation:Apoptosis is a programmed form of cell death involving the degradation of cellular constituents by a group of cysteine proteases called caspases. The caspases can be activated through either the intrinsic (mitochondrial mediated) or extrinsic (death receptor mediated) apoptotic pathways.
The intrinsic apoptotic pathway, also known as the mitochondrial pathway, is primarily initiated within the mitochondria. This pathway is activated in response to various internal stimuli, such as DNA damage, oxidative stress, and other cellular stresses.
When the intrinsic pathway is triggered, several events occur in the mitochondria:
- Release of cytochrome c: Cytochrome c is released from the mitochondrial intermembrane space into the cytoplasm.
- Formation of the apoptosome: Cytochrome c in the cytoplasm binds to apoptotic protease activating factor-1 (Apaf-1) and procaspase-9, forming a complex known as the apoptosome.
- Activation of caspase-9: The apoptosome activates caspase-9, an initiator caspase.
- Caspase cascade: Activated caspase-9 then activates executioner caspases, such as caspase-3, leading to the execution phase of apoptosis, which results in the orderly dismantling of the cell.
The mitochondria play a crucial role in this pathway by regulating the release of pro-apoptotic factors that are essential for the activation of downstream apoptotic processes.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 107
Correct
-
Cytochrome p450 enzymes expressed in hepatocytes serve to?
Your Answer: Facilitate oxidations or hydrolysis of drugs.
Explanation:Cytochrome p 450 are a family of proteins involved in drug metabolism which accounts for about 75% of the total metabolism. Most drugs are deactivated directly or by facilitated excretion from the body.
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This question is part of the following fields:
- Hepatobiliary
- Medicine
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Question 108
Correct
-
One function of the liver is synthesis and storage of protein. Which of the following will result in hypoalbuminemia?
Your Answer: All of the above
Explanation:Both trauma and sepsis cause an acute inflammatory response causing plasma leakage of albumin. Nephropathy causes leakage of albumin from glomeruli and excretion of albumin in urine known as albuminuria. A hypercatabolic state is characterized by increased circulating catabolic hormones and increase break down of proteins.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 109
Incorrect
-
In response to tissue injury, which of these cannot sensitize and activate nociceptors?
Your Answer: Histamine
Correct Answer: Calcium
Explanation:Histamine, serotonin, bradykinin and prostaglandin are all chemical mediators of inflammation with different distinct functions however all activate nociceptors. Calcium on the other hand cannot sensitize or activate nociceptors.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 110
Incorrect
-
Stroke volume in a average sized man lying in supine position is about?
Your Answer: 5l/min
Correct Answer: 70 ml
Explanation:The stroke volume of an average sized man who is lying is the supine position is about 70 ml.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 111
Incorrect
-
Which receptor type is associated with the inhibition of pancreatic endocrine secretion?
Your Answer: Β2
Correct Answer: Α2
Explanation:The activation of alpha 2-adrenergic receptors in pancreatic beta-cells works by inhibiting the secretion of insulin.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 112
Correct
-
Which of the following is NOT a component of bile?
Your Answer: Unconjugated bilirubin
Explanation:The composition of gallbladder bile is 97% water, 0.7% bile salts, 0.2% bilirubin, 0.51% fats (cholesterol, fatty acids and lecithin), and 200 meq/l inorganic salts (electrolytes).
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 113
Incorrect
-
All of the following are Vitamin K-dependent clotting factors except:
Your Answer: Factor IX
Correct Answer: Factor XI
Explanation:Activated Vitamin K is used to gamma carboxylate (and thus activate) certain enzymes involved in coagulation: Factors II, VII, IX, X, and protein C and protein S. Inability to activate the clotting cascade via these factors leads to the bleeding symptoms
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This question is part of the following fields:
- Haematology
- Medicine
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Question 114
Correct
-
Nitric oxide triggers vascular smooth muscle contraction through activation of which enzyme?
Your Answer: Guanylyl cyclase
Explanation:Impaired production or excess catabolism of NO impairs this endothelium-dependent vasodilator function and may contribute to excessive vasoconstriction under various pathological situations.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 115
Incorrect
-
Which of the following statements are true regarding human herpesvirus eight
Your Answer: It is associated with the development of Burkitt's lymphoma.
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 116
Incorrect
-
A 50-year-old male was brought to the ER after the accidental consumption of 300 ml of diethylene glycol. Blood investigations were suggestive of metabolic acidosis and renal failure. What is the appropriate management in this patient?
Your Answer: Forced diuresis
Correct Answer: Haemodialysis and oral ethanol
Explanation:Among the given options the most appropriate management in this patient would be ethanol and haemodialysis.Ethanol competes with ethylene glycol for alcohol dehydrogenase and thus, helps manage a patient with ethylene glycol toxicity.Ethylene glycol is a type of alcohol used as a coolant or antifreezeFeatures of toxicity are divided into 3 stages:Stage 1: (30 min to 12 hours after exposure) Symptoms similar to alcohol intoxication: confusion, slurred speech, dizziness (CNS depression)Stage 2: (12 – 48 hours after exposure) Metabolic acidosis with a high anion gap and high osmolar gap. Also tachycardia, hypertensionStage 3: (24 – 72 hours after exposure) Acute renal failureManagement has changed in recent times:Fomepizole, an inhibitor of alcohol dehydrogenase, is now used first-line in preference to ethanol.Ethanol has been used for many years works by competing with ethylene glycol for the enzyme alcohol dehydrogenase this limits the formation of toxic metabolites (e.g. glycolaldehyde and glycolic acid) which are responsible for the hemodynamic/metabolic features of poisoning.Haemodialysis has a role in refractory cases.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 117
Correct
-
The following contributes to the rate of depolarization?
Your Answer: All of the options given
Explanation:Depolarization occurs due to impulses generated by the SA node. As the heart beats to the rhythm of the SA node, certain factors will effect the rate of depolarization. All the mentioned options effect the rate of depolarization.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 118
Incorrect
-
Type 2 hypersensitivity is mediated by:
Your Answer: IgF
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 119
Incorrect
-
In the blood supply of the heart, ‘dominance’ refers to the coronary artery which supplies the?
Your Answer: Anterior interventricular artery
Correct Answer: Posterior interventricular artery
Explanation:Dominance of the coronary artery system is defined by the artery that gives rise to the posterior interventricular artery. Dominance of the right coronary artery is more common (68%). It gives rise to the large posterior interventricular branch which goes down to the apex of the heart.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 120
Incorrect
-
Neurons that are inactive during quiet breathing, become active when the respiratory drive for increased ventilation becomes greater than normal. These are located in the:
Your Answer: Pneumotaxic centre
Correct Answer: Ventral respiratory group
Explanation:The mechanism of control of ventilation is an interplay of multiple regions in the brain. Medullary respiratory centre sets the basic rhythm of breathing. The dorsal respiratory group integrates input from the stretch receptors and the chemoreceptors in the periphery and is composed mainly of inspiratory neurons which controls the basic rhythm of breathing. The ventral respiratory group generates breathing rhythm and integrates data coming in to the medulla. It contains both inspiratory and expiratory neurons. They are primarily active in exercise and stress.
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This question is part of the following fields:
- Medicine
- Respiratory
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Question 121
Incorrect
-
Which of the following structures of the cardiac conduction system is located in the right posterior portion of the interatrial septum?
Your Answer: SA node
Correct Answer: AV node
Explanation:AV node is located at the right posterior portion of the interatrial septum.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 122
Correct
-
Which part of the chromosome plays a role in preserving its integrity and stability?
Your Answer: Telomere
Explanation:Telomeres are non coding DNA plus proteins that are found at the end of the linear chromosomes. They maintain the integrity of the chromosomes and prevent their shortening
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This question is part of the following fields:
- Genetics
- Medicine
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Question 123
Incorrect
-
Which of the following runs in the upper part of the falx cerebri?
Your Answer: Inferior sagittal sinus
Correct Answer: Superior sagittal sinus
Explanation:Falx cerebri is a sickle cell fold of dura between the two hemispheres. Its posterior part blends with the superior part of the tentorium cerebelli. The superior sagittal sinus runs in its upper fixed margin, the inferior sagittal sinus in the free concave margin and the straight sinus along its attachment to the tentorium cerebelli.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 124
Incorrect
-
Which of the following are true when it comes to tumour suppressor genes:
Your Answer: Viruses can inactivate tumour suppressor genes
Correct Answer: All of the options are true
Explanation:All of the above mentioned statements are true regarding tumour suppressor genes. Tumour suppressor genes generally follow the two-hit hypothesis, which implies that both alleles that code for a particular protein must be affected before an effect is manifested.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 125
Incorrect
-
Which of the following stimulates glucagon release?
Your Answer: Phenytoin
Correct Answer: Exercise
Explanation:Studies have shown a small increase in glucagon levels during stress tests and exercise. This occurs in response to the reduction of blood glucose levels during physical activity; epinephrine levels are also a stimulus for the release of glucagon during exercise, since it suppresses insulin, which accounts for its stimulatory effects on glucagon. The use of stored fats for energy during exercise also stimulates the release of glucagon.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 126
Incorrect
-
Among the following which is the beneficial effect of nitro-glycerine?
Your Answer: Increase of left ventricular preload
Correct Answer: Dilation of systemic veins
Explanation:Dilation of systemic veins is a beneficial effect of nitro-glycerine.Administration of nitro-glycerine results in the dilation of systemic veins and decrease of myocardial wall tension and oxygen demand. Dilatation of systemic veins can cause reduced systemic vascular resistance leading to reduced cardiac workload thus reducing anginal symptoms secondary to demand ischemia.This is accompanied by vasodilation of large and medium-sized coronary arteries with increased coronary blood flow to the sub endocardium.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 127
Incorrect
-
Which of the following drugs would be the safest to prescribe in a 22 year old man with seropositive rheumatoid arthritis who is planning to start a family?
Your Answer: Sulfasalazine
Correct Answer: Prednisolone
Explanation:Prednisolone although has many undesirable side effects it may be considered relatively safe compared to the drugs that are provided here. Prolonged treatment with sulphasalazine may depress semen quality and cause irreversible infertility. Methotrexate and leflunomide both inhibit purine/pyrimidine synthesis (the former by inhibiting folate metabolism) and are contraindicated in pregnancy or while trying to conceive. In males, a temporary or permanent decrease in sperm count may occur with cyclophosphamide. Because the recovery of fertility after cyclophosphamide therapy is variable, sperm banking should be considered before treatment is begun.
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This question is part of the following fields:
- Connective Tissue
- Medicine
-
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Question 128
Incorrect
-
Which of the following is the most common clinical feature of carbon monoxide poisoning?
Your Answer: Cherry red skin
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 129
Correct
-
Which mechanism of action do Quinolones use?
Your Answer: Inhibit DNA gyrase
Explanation:The quinolones are a family of synthetic broad-spectrum antibiotic drugs. Quinolones exert their antibacterial effect by preventing bacterial DNA from unwinding and duplicating.
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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Question 130
Incorrect
-
Which of the following normally has a slow depolarizing “prepotential”?
Your Answer:
Correct Answer: Sinoatrial node
Explanation:There are 2 main types of action potentials (AP) in the heart, the slow response and the fast response:The slow response is initiated by the slow calcium-sodium channels, found in the SA node (which is the natural pacemaker of the heart) and the conduction fibers of the AV node.The fast response occurs in the atrial and ventricles muscle cells and the purkinje fibers.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 131
Incorrect
-
What is the function of the macula densa, located in the wall of the thick ascending limb?
Your Answer:
Correct Answer: Tubuloglomerular feedback.
Explanation:Macula densa cells sense changes in sodium chloride level, and will trigger an autoregulatory response to increase or decrease reabsorption of ions and water to the blood (as needed) in order to alter blood volume and return blood pressure to normal. Tubuloglomerular feedback is one of several mechanisms the kidney uses to regulate glomerular filtration rate (GFR). It involves the concept of purinergic signalling, in which an increased distal tubular sodium chloride concentration causes a basolateral release of adenosine from the macula densa cells. This initiates a cascade of events that ultimately brings GFR to an appropriate level.
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This question is part of the following fields:
- Medicine
- Renal
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Question 132
Incorrect
-
The primary sensory cortex is:
Your Answer:
Correct Answer: Brodmann area 3,1,2
Explanation:A Brodmann area in the brain is defined by cytoarchitecture, histology and organization of cells:Primary somatosensory cortex is areas 3,1, and 2Primary Motor 4Premotor 6Primary Visual 17Primary Auditory 41Brocas 44
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This question is part of the following fields:
- Medicine
- Neurology
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Question 133
Incorrect
-
Question 134
Incorrect
-
Xanthines (for example Caffeine), exhibit their positive inotropic effect by:
Your Answer:
Correct Answer: Inhibiting the breakdown cAMP
Explanation:Xanthines exert their positive inotropic effect by inhibiting the breakdown of the cAMP resulting in stronger and sustained contraction.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 135
Incorrect
-
An 81-year-old male presented to the emergency department following a fall at home. He was diagnosed with osteoporosis about five years ago. He presently complains of significant low back pain. A lumbar spine X-ray was suggestive of a fractured lumbar vertebra. A subsequent MRI scan of the lumbosacral spine revealed a new L3 burst fracture with no evidence of cord compression. A neurosurgical consult was sought and conservative management was planned accordingly in the form of pain control, physiotherapy, and mobilization (as allowed by the pain). He also has been diagnosed with chronic renal disease (stage IV) with a creatinine clearance of 21ml/min, he was started on a Buprenorphine patch. Which of the following opioids would be safest to use for his breakthrough pain?
Your Answer:
Correct Answer: Oxycodone
Explanation:Oxycodone is a safer opioid to use in patients with moderate to end-stage renal failure.Active metabolites of morphine accumulate in renal failure which means that long-term use is contraindicated in patients with moderate/severe renal failure. These toxic metabolites can accumulate causing toxicity and risk overdose. Oxycodone is mainly metabolised in the liver and thus safer to use in patients with moderate to end-stage renal failure with dose reductions.Adverse effects:Constipation is the most common overall side effect. Others include: asthenia, dizziness, dry mouth, headache, nausea, pruritus, etc. Medications in renal failure:Drugs to be avoided in patients with renal failureAntibiotics: tetracycline, nitrofurantoinNSAIDsLithiumMetforminDrugs that require dose adjustment:Most antibiotics including penicillin, cephalosporins, vancomycin, gentamicin, streptomycinDigoxin, atenololMethotrexateSulphonylureasFurosemideOpioidsRelatively safe drugs:Antibiotics: erythromycin, rifampicinDiazepamWarfarin
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 136
Incorrect
-
A 41 year old woman who has a history of SLE presents with a dry cough, dyspnoea and fever. She is being treated with a monthly dose of IV cyclophosphamide for Grade IV nephropathy. The last cyclophosphamide dose was 10 years ago. Lab investigations are as follows: WCC: 2.3 (lymphocyte count 0.7)Platelets: 81Hb: 10.5ESR: 56CRP: 43PO2: 7.2 kPa, PCO2: 3.6 kPa after walking out to the toilet.Chest X ray was unremarkable apart from some patchy pulmonary infiltration.What is the likely diagnosis?
Your Answer:
Correct Answer: Pneumocystis carinii pneumonia (PCP)
Explanation:Pneumocystis carinii pneumonia, is an opportunistic fungal lung infection occurring almost exclusively in immunocompromised individuals. In 50% of cases, PCP is the first manifestation of AIDS (acquired immune deficiency syndrome), but it may be caused by other immunodeficiency disorders. PCP should be suspected in patients with a history of progressive dyspnoea and a dry cough with resistance to standard antibiotic treatment. Signs that support this diagnosis include a CD4 count < 200/μL, an increased beta-D-glucan level, and diffuse bilateral infiltrates on chest x-ray. Management of PCP includes high-dose trimethoprim/sulfamethoxazole (TMP/SMX), treatment of the underlying immunodeficiency disorder, and steroids in the case of severe respiratory insufficiency. TB is less likely to be present in this case as ESR is relatively low and chest x-ray appeared normal.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 137
Incorrect
-
The steps of cardiac cycle in sequence are:
Your Answer:
Correct Answer: Isovolumic contraction, ejection, isovolumic relaxation, passive ventricular filling, active ventricular filling.
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.1st stage: diastole, or passive filling 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. 2nd stage: atrial systole, is when the atrium contracts, and blood flows from atrium to the ventricle (active filling).3rd stage: isovolumic contraction is when the ventricles begin to contract, the AV and semilunar valves close, and there is no change in volume. 4th stage: ventricular ejection, is when the ventricles are contracting and emptying, and the semilunar valves are open. 5th 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 138
Incorrect
-
Dynein proteins transmit polypeptides/proteins in which direction?
Your Answer:
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 139
Incorrect
-
As assessed by immunocytochemistry and electron microscopy, the anterior pituitary gland contains how many different types of cells?
Your Answer:
Correct Answer: 5
Explanation:The pituitary is divided into three sections
-the anterior lobe which constitute the majority of the pituitary mass and is composed primarily of five hormone-producing cell types (thyrotropes, lactotropes, corticotropes, somatotropes and gonadotropes) each secreting thyrotropin, prolactin, ACTH, growth hormone and gonadotropins (FSH and LH) respectively.
There is also a sixth cell type in the anterior lobe -the non-endocrine, agranular, folliculostellate cells.
The intermediate lobe produces melanocyte-stimulating hormone and endorphins, whereas the posterior lobe secretes anti-diuretic hormone (vasopressin) and oxytocin.
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This question is part of the following fields:
- Endocrinology
- Medicine
-
-
Question 140
Incorrect
-
The chief cells of the stomach secrete which of the following?
Your Answer:
Correct Answer: Pepsinogens
Explanation:A gastric chief cell (or peptic cell, or gastric zymogenic cell) is a type of cell in the stomach that releases pepsinogen and gastric lipase.
-
This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 141
Incorrect
-
What is the average life span of neutrophils?
Your Answer:
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.
-
This question is part of the following fields:
- Haematology
- Medicine
-
-
Question 142
Incorrect
-
A 62 year old man arrives at the clinic with a history of cough and intermittent haemoptysis for the last 3 months. He has a 50 pack year smoking history and is currently waiting for bronchoscopy to assess a left lower lobe collapse. The patient also has a marked muscle weakness and wasting of proximal muscles of his shoulders and pelvic girdle. His wife states that lately he has been unable to eat solids. Which of the following statements would be true regarding this scenario?
Your Answer:
Correct Answer: He may have a photosensitive facial rash
Explanation:The patient has presented with signs of small cell lung cancer. The associated proximal muscle weakness is most probably due to dermatomyositis which occurs as a paraneoplastic syndrome associated with lung carcinoma. In most cases, the first symptom is a distinctive skin rash on the face, eyelids, chest, nail cuticle areas, knuckles, knees or elbows. The rash is patchy and usually a bluish-purple colour. Corticosteroids are helpful in the management of the cutaneous changes and muscle weakness.
-
This question is part of the following fields:
- Connective Tissue
- Medicine
-
-
Question 143
Incorrect
-
The TSH receptor produces its effects in the thyrocyte via:
Your Answer:
Correct Answer: G-protein coupled activation of adenylyl cyclise and phospholipase c
Explanation:The thyrotropin receptor, also known as TSH receptor, responds to the thyroid stimulating hormone or thyrotropin to stimulate production of T3 and T4. It is a G protein-coupled receptor which leads to stimulation of phospholipase C and adenylyl cyclase, mediated by Gq/11 and Gs.
-
This question is part of the following fields:
- Endocrinology
- Medicine
-
-
Question 144
Incorrect
-
During which stage of sleep is muscle tone in the limbs most reduced?
Your Answer:
Correct Answer: REM
Explanation:Rapid eye movement (REM) stage is marked by extensive physiological changes in the body, such as accelerated respiration, increased brain activity and muscle relaxation. People dream during REM sleep, perhaps as a result of excited brain activity and the paralysis of major voluntary muscles.
-
This question is part of the following fields:
- Medicine
- Neurology
-
-
Question 145
Incorrect
-
Depolarization spreads rapidly through cardiac muscle fibers because of the presence of:
Your Answer:
Correct 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.
-
This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 146
Incorrect
-
Which statement is correct about the clinical state of methemoglobinemia?
Your Answer:
Correct Answer: May arise due to a hereditary deficiency of NADH.
Explanation:Methaemoglobin is a form of haemoglobin that contains ferric [Fe3+] iron and has a decreased ability to bind oxygen. Spontaneously formed methaemoglobin is normally reduced by protective enzyme systems, e.g., NADH methaemoglobin reductase, hence a deficiency of NADH may result in increased levels of methaemoglobin
-
This question is part of the following fields:
- Haematology
- Medicine
-
-
Question 147
Incorrect
-
The hepatic portal vein:
Your Answer:
Correct Answer: Carries mainly nutrients from the GIT.
Explanation:The portal vein contains oxygen as any other vein in the body does. The hepatic veins are responsible for venous drainage of the liver. The main function of the portal vein is to carry absorbed nutrients in the gut for metabolism and detoxification.
-
This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 148
Incorrect
-
Which of the following with regard to autosomal dominant disorders are true:
Your Answer:
Correct Answer: The offspring of a heterozygous individual has a 50% chance of inheriting the chromosome carrying the disease allele
Explanation:50% of the children will be effected from parents who are heterozygous for an autosomal dominant disorder. An allele can be dominant or recessive. Individuals, meanwhile, can be homozygous or heterozygous: individuals who are homozygous for a certain gene carry two copies of the same allele. individuals who are heterozygous for a certain gene carry two different alleles.
-
This question is part of the following fields:
- Genetics
- Medicine
-
-
Question 149
Incorrect
-
A 45-year-old male is brought to the emergency department after being found collapsed, outside a nightclub. The ER team found an empty bottle of amyl nitrate in his pocket. The patient is hypoxic with an O2 saturation of 84% and is confused. Which of the following is the best treatment for this patient?
Your Answer:
Correct Answer: Methylene blue
Explanation:The best treatment for the patient in question would be methylene blue.The most probable diagnosis in this patient is methemoglobinemia due to the ingestion of amyl nitrate.Amyl nitrate promotes the formation of methaemoglobin, which avidly conserves oxygen and leads to decreased tissue oxygen saturations. Treatment of choice includes methylene blue and vitamin C.Adverse effects:Benign side effects include green or blue discoloration of urine and patients should be forewarned. Significant side effects are based on methylene blue, itself, being an oxidizing agent and an inhibitor of monoamine oxidase A (MAO-A). As an oxidizing agent, methylene blue can actually precipitate methemoglobinemia or haemolysis in high doses or when ineffectively reduced. Methylene blue administration in a patient taking a serotonergic agents may predispose to serotonin syndrome.Note: Although methylene blue administration is controversial in the setting of G6PD-deficiency due to reduced levels of NADPH, it is not contraindicated and should be administered cautiously and judiciously.
-
This question is part of the following fields:
- Medicine
- Pharmacology
-
-
Question 150
Incorrect
-
In the event of an overdose, haemodialysis is ineffective as a treatment modality for which of the following drugs?
Your Answer:
Correct Answer: Tricyclics
Explanation:Tricyclic compounds can’t be cleared by haemodialysis.Drugs that can be cleared with haemodialysis include: (BLAST)- Barbiturate- Lithium- Alcohol (inc methanol, ethylene glycol)- Salicylates- Theophyllines (charcoal hemoperfusion is preferable)Drugs which cannot be cleared with haemodialysis include:- Tricyclics- Benzodiazepines- Dextropropoxyphene (Co-proxamol)- Digoxin- Beta-blockers
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This question is part of the following fields:
- Medicine
- Pharmacology
-
-
Question 151
Incorrect
-
Major supplies of glycogen are found in ….
Your Answer:
Correct 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.
-
This question is part of the following fields:
- Medicine
- Metabolism
-
-
Question 152
Incorrect
-
Concerning surface anatomy, where is the base of the heart
Your Answer:
Correct Answer: 2nd left costal to 3rd right costal cartilage
Explanation:The base of the heart, also known as the superior border of the heart corresponds to a line connecting the inferior border of the 2nd left costal cartilage to the superior border of the 3rd right costal cartilage.
-
This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 153
Incorrect
-
The sympathetic supply to the stomach comes from the:
Your Answer:
Correct Answer: Celiac plexus
Explanation:The vagus nerve supplies the stomach and up to proximal two-thirds of the large intestine and has parasympathetic stimulation. The sympathetic chain which begins at the level of he 1st thoracic vertebra and extends up to 3rd lumbar vertebra gives off the celiac plexus which mainly supplies the stomach. The mesenteric plexus mainly supplies the small intestine and is located below the celiac plexus in the sympathetic chain.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 154
Incorrect
-
Water hammer pulse is found in:
Your Answer:
Correct Answer: Aortic insufficiency
Explanation:Watson’s water hammer pulse is the medical sign which describes a pulse that is bounding and forceful, rapidly increasing and subsequently collapsing, as if it were the sound of a water hammer that was causing the pulse. A water hammer was a Victorian toy in which a tube was half filled with fluid, the remainder being a vacuum. The child would invert and reinvert the tube; each time the impact of the fluid at each end would sound like a hammer blow. This is associated with increased stroke volume of the left ventricle and decrease in the peripheral resistance leading to the widened pulse pressure of aortic regurgitation.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 155
Incorrect
-
Which of the following is a granulocyte?
Your Answer:
Correct 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
-
This question is part of the following fields:
- Haematology
- Medicine
-
-
Question 156
Incorrect
-
Factors influencing cardiac output include which of the following?
Your Answer:
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.
-
This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 157
Incorrect
-
Choose the correct statement regarding trabecular bone:
Your Answer:
Correct Answer: All of the options are correct
Explanation:Trabecular, spongy or cancellous bone. It is located inside the cortical bone and makes up around 20% of all bone in the body. It is made of spicules or plates with a high surface to volume ratio, where many cells sit on the surface of the end plates. It receives its nutrients from the extracellular fluid (ECF), exchanging about 10 mmol of calcium every 24 hours.
-
This question is part of the following fields:
- Endocrinology
- Medicine
-
-
Question 158
Incorrect
-
A 32 year old complains of pain in her hands bilaterally. Which of the following symptoms would point towards an inflammatory joint disease such as rheumatoid arthritis?
Your Answer:
Correct Answer: Marked stiffness for more than an hour in the mornings
Explanation:In rheumatoid arthritis (RA), clinical symptoms of joint stiffness, pain, and functional disability are commonly most severe in the early morning. These symptoms closely follow the circadian rhythm of the pro-inflammatory cytokine, interleukin (IL)-6. In RA, the increase in nocturnal anti-inflammatory cortisol secretion is insufficient to suppress ongoing inflammation, resulting in the morning symptoms characteristic of RA. Established diagnostic criteria for RA include prolonged morning stiffness that could last up to an hour. Loss of joint mobility, pain, malaise and swelling of finger joints are features that are not specific to rheumatoid arthritis, and are found in many other conditions.
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This question is part of the following fields:
- Connective Tissue
- Medicine
-
-
Question 159
Incorrect
-
What does a deficiency of adenosine deaminase lead to?
Your Answer:
Correct Answer: SCID
Explanation:Severe combined immunodeficiency, SCID, also known as alymphocytosis, Glanzmann–Riniker syndrome, severe mixed immunodeficiency syndrome, and thymic alymphoplasia,[1] is a rare genetic disorder characterized by the disturbed development of functional T cells and B cells. Most cases of SCID are due to mutations in the gene encoding the common gamma chain (γc), a protein that is shared by the receptors for interleukins. The second most common form of SCID after X-SCID is caused by a defective enzyme, adenosine deaminase (ADA), necessary for the breakdown of purines.
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This question is part of the following fields:
- Medicine
- Metabolism
-
-
Question 160
Incorrect
-
Impulse conduction through the AV node is slow and depends on the action potential produced by which of the following.
Your Answer:
Correct Answer: Calcium flux
Explanation:The action potentials in the SA and AV nodes are largely due to Ca2+, with no contribution by Na+ influx.
-
This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 161
Incorrect
-
The main breakdown of fatty acids (by B-oxidation) occurs in which part of the cell?
Your Answer:
Correct Answer: Mitochondria
Explanation:Once inside the mitochondria, the β-oxidation of fatty acids occurs via five recurring steps:Activation by ATPOxidation by FAD,Hydration,Oxidation by NAD+,Thiolysis,The final product is acetyl-CoA, the entry molecule for the citric acid cycle.
-
This question is part of the following fields:
- Medicine
- Metabolism
-
-
Question 162
Incorrect
-
Which part of the cerebellum is primarily responsible for interacting with the motor cortex and planning and programming movements?
Your Answer:
Correct Answer: Cerebrocerebellum
Explanation:The cerebrocerebellum is the largest functional subdivision of the cerebellum, comprising of the lateral hemispheres and the dentate nuclei. It is involved in the planning and timing of movements, and in the cognitive functions of the cerebellum.
-
This question is part of the following fields:
- Medicine
- Neurology
-
-
Question 163
Incorrect
-
A 56 year old woman presents to the clinic complaining of shoulder pain that she has been experiencing for the last 4 weeks. She does not remember getting injured previously. The pain worsens on movement especially when she is moving the arm quickly. At night, lying on the affected side is painful. Examination reveals no erythema or swelling. However, pain is felt on passive abduction between 60 to 120 degrees and she is unable to abduct the arm past 70-80 degrees. Flexion and extension are intact. What is the most likely diagnosis?
Your Answer:
Correct Answer: Supraspinatus tendonitis
Explanation:Supraspinatus tendinopathy is a common and disabling condition that becomes more prevalent after middle age and is a common cause of pain in the shoulder. A predisposing factor is resistive overuse. This patient has the classic painful arc that is a sign of shoulder impingement characteristic of supraspinatus tendonitis.
-
This question is part of the following fields:
- Connective Tissue
- Medicine
-
-
Question 164
Incorrect
-
Which of the following derivatives of proopiomelanocortin is an opioid peptide?
Your Answer:
Correct Answer: ß-endorphin
Explanation:ß-endorphin is an endogenous opioid neuropeptide which is mainly synthesized and stored in the anterior pituitary gland, derived from the precursor proopiomelanocortin (POMC). Some studies have shown that immune system cells are also capable of synthesizing ß-endorphin. β-endorphin is thought to exert a tonic inhibitory influence upon GNRH secretion and to be an important regulator of reproductive function.
-
This question is part of the following fields:
- Endocrinology
- Medicine
-
-
Question 165
Incorrect
-
The axons of which neurons serve as the only output from the cerebellar cortex?
Your Answer:
Correct 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.
-
This question is part of the following fields:
- Medicine
- Neurology
-
-
Question 166
Incorrect
-
Question 167
Incorrect
-
Southern Blotting and DNA probes:
Your Answer:
Correct 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.
-
This question is part of the following fields:
- Genetics
- Medicine
-
-
Question 168
Incorrect
-
Which of the following describes a principal action of insulin?
Your Answer:
Correct Answer: Inhibition of phosphorylase and gluconeogenic enzymes
Explanation:Insulin stimulates glycolysis and lipogenesis, but inhibits gluconeogenesis. Insulin promotes the dephosphorylating of glycogen phosphorylase, therefore suppressing glycogenolysis. Insulin also inhibits FOX3, FOX4, and FOX6 and their ability to promote hepatic gluconeogenesis.
-
This question is part of the following fields:
- Endocrinology
- Medicine
-
-
Question 169
Incorrect
-
The nucleus tractus solitaries is medullary nucleus that processes the following inputs except:
Your Answer:
Correct Answer: Sensory input from the semi-circular canal (CN VIII)
Explanation:Located in the brain stem is a series of purely sensory nuclei known as tractus solitaries. Inputs of the nucleus tractus solitaries include:Taste information from the facial nerve (anterior 2/3 of the tongue), glossopharyngeal nerve (posterior 1/3) and vagus nerve (small area on the epiglottis).Sensory information from the ear (auricular branch of the vagus nerve).Chemoreceptors and mechanoreceptors of the general visceral afferent pathway (GVA) in the carotid body via glossopharyngeal nerve, aortic bodies, and the sinoatrial node, via the vagus nerve.Chemically and mechanically sensitive neurons of the general visceral afferent pathway (GVA) with endings located in the heart, lungs, airways, gastrointestinal system, pharynx, and liver via the glossopharyngeal and vagus nerves.
-
This question is part of the following fields:
- Medicine
- Neurology
-
-
Question 170
Incorrect
-
Question 171
Incorrect
-
ANP and BNP in the circulation act on the kidney to?
Your Answer:
Correct Answer: Increase sodium excretion
Explanation:The physiologic actions of BNP are similar to those of ANP and include decrease in systemic vascular resistance and central venous pressure as well as an increase in natriuresis (sodium excretion). The net effect of these peptides is a decrease in blood pressure due to the decrease in systemic vascular resistance and, thus, afterload.
-
This question is part of the following fields:
- Medicine
- Renal
-
-
Question 172
Incorrect
-
The complex twisting and folding of peptide chains describes which order of protein structure?
Your Answer:
Correct Answer: Secondary structure
Explanation:Secondary Structure refers to the coiling or folding of a polypeptide chain that gives the protein its 3-D shape. There are two types of secondary structures: the alpha (α) helix and the beta (β) pleated sheet.
-
This question is part of the following fields:
- Medicine
- Metabolism
-
-
Question 173
Incorrect
-
The major factor in controlling coronary artery blood flow is considered to be?
Your Answer:
Correct Answer: Metabolites of oxygen consumption
Explanation:There is a strong relationship between myocardial blood flow and oxygen consumption. This indicates that products of metabolism may cause vasodilation of the coronary artery.
-
This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 174
Incorrect
-
The following cells replicate without shortening their telomeres because they express telomerase.
Your Answer:
Correct Answer: Germ cells
Explanation:Telomerase activity is seen in germ cells and is absent in somatic cells. Telomeres prevent the chromosomes from shortening and prevent the coding portion of the DNA from being lost, thus allowing the cell to replicate indefinitely. During replication telomeres may be lost resulting in cell death.
-
This question is part of the following fields:
- Genetics
- Medicine
-
-
Question 175
Incorrect
-
Question 176
Incorrect
-
The percentage of blood supplied to the liver by the hepatic artery is?
Your Answer:
Correct Answer: 25%
Explanation:The liver receives a dual blood supply from the hepatic portal vein and hepatic arteries. The hepatic portal vein delivers approximately 75% of the liver’s blood supply, and carries venous blood drained from the spleen, gastrointestinal tract, and its associated organs. The hepatic arteries supply arterial blood to the liver, accounting for the remaining quarter of its blood flow. Oxygen is provided from both sources; approximately half of the liver’s oxygen demand is met by the hepatic portal vein, and half is met by the hepatic arteries
-
This question is part of the following fields:
- Hepatobiliary
- Medicine
-
-
Question 177
Incorrect
-
In the gastric mucosa, which of the following cells is known to secrete gastric lipase?
Your Answer:
Correct Answer: Chief cell
Explanation:Chief cells produce pepsinogen and gastric lipase. Parietal cells produce stomach acid and intrinsic factor.
-
This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 178
Incorrect
-
Which of the following statements regarding influenza virus is correct?
Your Answer:
Correct Answer: Influenza is a RNA virus
Explanation:The Orthomyxoviruses are a family of RNA viruses that includes six genera: Influenza virus A, Influenza virus B, Influenza virus C, Isavirus, Thogotovirus and Quaranjavirus.The mechanism of the evolutionary force of antigenic shift allows influenza viruses to exchange genes with strains that infect different species. Under this mechanism, a human influenza virus could exchange genes with an avian strain, and that is how pandemic strains arise.
-
This question is part of the following fields:
- Infectious Diseases
- Medicine
-
-
Question 179
Incorrect
-
Calcium is transported over the brush border in the gut, via which transporter / channel?
Your Answer:
Correct Answer: TRPV 6
Explanation:Transient Receptor Potential Vanilloid 6 or TRPV 6 is a calcium channel located in the cell membrane which is present in a variety of organs, including small intestine, oesophagus, stomach, colon, placenta, kidney, and uterus. In the intestine, it is located in the apical brush-border membrane of the enterocyte, regulating the entry of calcium into the cell.
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This question is part of the following fields:
- Endocrinology
- Medicine
-
-
Question 180
Incorrect
-
A 73-year-old female is being reviewed in the osteoporosis clinic. She had a fracture of her left hip 5 years ago and was started on alendronate. Following the development of persistent musculoskeletal pain, alendronate was replaced with risedronate, which was also stopped for similar reasons. Strontium ranelate was therefore started but was also stopped due to the development of deep vein thrombosis in the right leg. Her current T-score is -4.1. A decision is made to start a trial of denosumab. What is the mechanism of action of denosumab?
Your Answer:
Correct Answer: Inhibits RANK ligand, which in turn inhibits the maturation of osteoclasts
Explanation:The principal mechanism by which strontium inhibits osteoclast activity is by enhancing the secretion of osteoprotegerin (OPG) and by reducing the expression of the receptor activator of nuclear factor κB ligand (RANKL) in osteoblasts.Osteoporosis is defined as low bone mineral density caused by altered bone microstructure ultimately predisposing patients to low-impact, fragility fractures.Management:Vitamin D and calcium supplementation should be offered to all women unless the clinician is confident they have adequate calcium intake and are vitamin D repleteAlendronate is the first-line treatment. Around 25% of patients cannot tolerate alendronate, usually due to upper gastrointestinal problems. These patients should be offered risedronate or etidronate.Strontium ranelate and raloxifene are recommended if patients cannot tolerate bisphosphonates.Other medications that are useful in the treatment of osteoporosis are denosumab, teriparatide, raloxifene, etc.
-
This question is part of the following fields:
- Medicine
- Pharmacology
-
-
Question 181
Incorrect
-
The position of the kidneys besides the vertebral column retroperitoneally spans levels:
Your Answer:
Correct Answer: T12 – L3
Explanation:The asymmetry within the abdominal cavity, caused by the position of the liver, typically results in the right kidney being slightly lower and smaller than the left, and being placed slightly more to the middle than the left kidney. The left kidney is approximately at the vertebral level T12 to L3, and the right is slightly lower.
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This question is part of the following fields:
- Medicine
- Renal
-
-
Question 182
Incorrect
-
Which of the following pairs are correct concerning arteriolar tone?
Your Answer:
Correct Answer: Hormonal control: catecholamines affect the adrenergic receptors of the vascular smooth muscle
Explanation:Catecholamines released from the adrenal medulla act on the noradrenergic receptors of the vascular smooth muscles. In the skeletal muscles and liver it causes vasodilation whilst it causes vasoconstriction in the rest of the blood vessels of the body.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 183
Incorrect
-
The V wave in the jugular pulse is caused by:
Your Answer:
Correct Answer: Atrial filling
Explanation:The v wave reflects the passive increase in pressure and volume of the right atrium as it fills in late systole and early diastole.
The jugular vein pulsations usually have two elevations and two troughs. The first elevation (a wave) corresponds to the slight rise in atrial pressure resulting from atrial contraction. The first descent (x descent) reflects a fall in atrial pressure that starts with atrial relaxation. The second elevation (v wave) corresponds to ventricular systole when blood is entering the right atrium from the vena cavae while the tricuspid valve is closed. Finally, the second descent (y descent) reflects falling right atrial pressure as the tricuspid valve opens and blood drains from the atrium into the ventricle.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 184
Incorrect
-
Where is the carotid sinus located?
Your Answer:
Correct Answer: After the bifurcation of the carotid artery, on the internal carotid
Explanation:The carotid sinus is a small dilation in the internal carotid artery just above its bifurcation into the external and internal carotid branch. Baroreceptors are present at this dilation.
-
This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 185
Incorrect
-
Which enzyme is responsible for the removal of acetylcholine from the synapse?
Your Answer:
Correct Answer: Acetylcholinesterase
Explanation:Acetylcholinesterase is the enzyme that is responsible for breaking down acetylcholine into choline and acetate. Both of these molecules are transported back to the presynaptic neuron to be synthesized again. This enzyme is attached to the collagen fibers of the basement membrane in the synaptic cleft.
-
This question is part of the following fields:
- Medicine
- Neurology
-
-
Question 186
Incorrect
-
During which phase of the cardiac cycle does most of the ventricular filling occur?
Your Answer:
Correct Answer: Ventricular diastole
Explanation:During the phase of ventricular diastole when the heart muscle relaxes and all the valves are open, blood flows easily into the heart. This is the phase of rapid ventricular filling. During isovolumetric contraction and relaxation the volume of blood in the heart does not change. During ventricular ejection blood enters into the aorta and pulmonary vessels.
-
This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 187
Incorrect
-
In paralytic ileus the following are true except:
Your Answer:
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.
-
This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 188
Incorrect
-
Question 189
Incorrect
-
What is the principle site of action of adrenocorticotrophic hormone (ACTH)?
Your Answer:
Correct Answer: Adrenal gland
Explanation:Adrenocorticotropic hormone, also known as ACTH or corticotropin, is a polypeptide tropic hormone. It is synthesized by the corticotropic cells of the anterior pituitary. It works by regulating the secretion of glucocorticoid hormones from the cortex cells in the adrenal gland. It binds to the melanocortin (MC) 2 receptors on the surface of the adrenal zona glomerulosa cells, producing cortisol.
-
This question is part of the following fields:
- Endocrinology
- Medicine
-
-
Question 190
Incorrect
-
The main reason for the prolonged effect of the withdrawal reflex is:
Your Answer:
Correct 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
-
-
Question 191
Incorrect
-
Which one of the following conditions is least likely to be associated with pyoderma gangrenosum?
Your Answer:
Correct Answer: Syphilis
Explanation:The following are conditions commonly associated with pyoderma gangrenosum:
Inflammatory bowel disease:
- Ulcerative colitis
- Crohn’s disease
Arthritides:
- Rheumatoid arthritis
- Seronegative arthritis
Haematological disease:
- Myelocytic leukaemia
- Hairy cell leukaemia
- Myelofibrosis
- Myeloid metaplasia
- Monoclonal gammopathy
Autoinflammatory disease:
- Pyogenic sterile arthritis, pyoderma gangrenosum, and acne syndrome (PAPA syndrome)
- Granulomatosis with polyangiitis
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This question is part of the following fields:
- Dermatology
- Medicine
-
-
Question 192
Incorrect
-
An example of cholinergic autonomic neurons are:
Your Answer:
Correct Answer: Sympathetic postganglionic neurons that innervate sweat glands.
Explanation:All preganglionic neurons in both the sympathetic and parasympathetic nervous system secrete acetylcholine. The postganglionic neurotransmitter of the parasympathetic nervous system in all neurons is acetylcholine. Postganglionic fibers of the sympathetic nervous system mainly secrete Noradrenalin and Adrenalin but at sweat glands and erector pili muscles the postganglionic neurotransmitter is acetylcholine.
-
This question is part of the following fields:
- Medicine
- Neurology
-
-
Question 193
Incorrect
-
A 31 year old female with systemic lupus erythematosus wants to know if she has any predisposing factors for the disease. Which of the following carries the greatest risk of developing SLE?
Your Answer:
Correct Answer: Monozygotic twin
Explanation:An overall concordance rate in monozygotic twins was documented to be 25% as compared to dizygotic twins with 3%. First degree relatives have a chance of around 3% of developing the disease. Caucasians show an increase frequency of HLA-B8. The Japanese lupus patients had a stronger association with HLA-DR2.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 194
Incorrect
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Which clotting factor is responsible for stabilization of the fibrin clot by formation of covalent cross-linkages?
Your Answer:
Correct Answer: Factor XIIIa
Explanation:Factor XIII or fibrin stabilizing factor is an enzyme of the blood coagulation system that crosslinks fibrin. Deficiency of this factor (FXIIID) affects clot stability.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 195
Incorrect
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With regards to the function of the p53 protein produced by the p53 gene, which of the following statements is incorrect?
Your Answer:
Correct Answer: It permits repair of mutations and other defects in RNA
Explanation:The p53 protein is a crucial tumor suppressor and plays several key roles in maintaining cellular integrity:
- Nuclear transcription factor: p53 is a nuclear transcription factor that regulates the expression of various genes involved in cell cycle control, DNA repair, apoptosis, and senescence.
- DNA repair: p53 permits repair of mutations and other defects in DNA (not RNA). It activates the transcription of genes involved in DNA repair mechanisms, allowing the cell to correct errors before proceeding with the cell cycle.
- Cell cycle regulation: p53 can induce the expression of p21, a protein that inhibits cyclin-dependent kinases, thereby halting the cell cycle at the G1/S checkpoint to allow time for DNA repair or to trigger apoptosis if the damage is irreparable. Mutations in p53 may fail to halt the cell cycle, allowing mutations to persist and potentially leading to cancer.
- Apoptosis: If DNA damage is extensive and cannot be repaired, p53 triggers apoptosis to prevent the propagation of damaged cells.
- Suppression of proto-oncogenes: p53 indirectly contributes to the suppression of proto-oncogenes by preventing the proliferation of cells with damaged DNA, thereby reducing the risk of oncogenic transformation.
Given these functions, the statement that p53 “permits repair of mutations and other defects in RNA” is incorrect, as p53 is primarily involved in the repair of DNA, not RNA.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 196
Incorrect
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Which of the following limits the duration of inspiration and increases respiratory rate?
Your Answer:
Correct Answer: Pneumotaxic centre
Explanation:The mechanism of control of ventilation is an interplay of multiple regions in the brain. The medullary respiratory centre sets the basic rhythm of breathing and the pons modifies the output of the medullary centres. There are two pontine centres: apneustic and pneumotaxic.
The pnuemotaxic centre controls inspiratory time. Increased signals to this area increases respiratory rate. The dorsal respiratory group (DRG) integrates input from the stretch receptors and the chemoreceptors in the periphery and is composed mainly of inspiratory neurons. The DRG controls the basic rhythm of breathing by triggering inspiratory impulses. The ventral respiratory group (VRG) generates breathing rhythm and integrates data coming into the medulla and contains both inspiratory and expiratory neurons. They are primarily active in exercise and stress.
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This question is part of the following fields:
- Medicine
- Respiratory
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Question 197
Incorrect
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With regards to the cardiac cycle which of the following is true
Your Answer:
Correct Answer: Right atrial systole occurs before left atrial systole: as below
Explanation:Cardiac cycle: The first event in the cycle is atrial depolarization (a P wave on the surface ECG) follows by RIGHT ATRIAL and then LEFT ATRIAL contraction. Ventricular activation (QRS) follows after a short interval (the PR interval). LEFT VENTRICULAR contraction starts shortly thereafter RIGHT VENTRICULAR contraction begins. At the end, the aortic valve closure is followed by pulmonary valve closure.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 198
Incorrect
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Inhibition of cell division at the end of G1 occurs through:
Your Answer:
Correct Answer: Unphosphorolated retinoblastoma protein (uRb)
Explanation:A cell’s decision to enter, or re-enter, the cell cycle is made before S-phase in G1 at what is known as the restriction point, and is determined by the combination of promotional and inhibitory extracellular signals that are received and processed. Ultimately unphosphorylated Rb acts as an inhibitor of G1.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 199
Incorrect
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The structure of haemoglobin A in adults includes
Your Answer:
Correct Answer: Haem, globin polypeptide chains α and β
Explanation:Haemoglobin A (HbA), also known as adult haemoglobin or α2β2, is the most common human haemoglobin tetramer, comprising over 97% of the total red blood cell haemoglobin. It consists of two alpha chains and two beta chains.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 200
Incorrect
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What is the main reason for checking the urea and electrolytes prior to commencing a patient on amiodarone?
Your Answer:
Correct Answer: To detect hypokalaemia
Explanation:All antiarrhythmic drugs have the potential to cause arrhythmias. Coexistent hypokalaemia significantly increases this risk.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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SESSION STATS - PERFORMANCE PER SPECIALTY
