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Question 1
Correct
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Which of the following conditions results from chromosomal ‘non-disjunction’?
Your Answer: All of the options
Explanation:Non-disjunction can result in aneuploidy i.e. abnormal number of chromosomes in a cell. It results due to uneven division of chromosomes in the meiosis 1 or 2 phase. All the above mentioned examples are of non-disjunction.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 2
Incorrect
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Regarding Polymerase Chain Reaction, all are true except:
Your Answer: DNA is initially denatured by heat into single stranded DNA prior to cooling
Correct Answer: There is a linear rise of DNA copies during amplification.
Explanation:All are true except there is a linear rise of DNA copies during amplification. There is an exponential rise in amplification of DNA.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 3
Correct
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The extrinsic coagulation pathway is initiated by activation of which clotting factor?
Your Answer: Factor VII
Explanation:The tissue factor pathway (extrinsic) begins following damage to the blood vessel. FVII leaves the circulation and comes into contact with tissue factor (TF) expressed on tissue-factor-bearing cells (stromal fibroblasts and leukocytes), forming an activated complex (TF-FVIIa).
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This question is part of the following fields:
- Haematology
- Medicine
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Question 4
Incorrect
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What is the function of cytotoxic T cells?
Your Answer: Kill by initiating apoptosis
Correct Answer: Kill by inserting perforins and by initiating apoptosis
Explanation:Cytotoxic T cells, once activated, approach the infected cell, insert perforins and release granzymes inducing apoptosis.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 5
Incorrect
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Which of the following takes place during fasting
Your Answer: Alternating segmental contractions
Correct Answer: Migrating motor complex
Explanation:Migrating motor complexes (MMC) are waves of electrical activity that sweep through the intestines in a regular cycle during fasting. These motor complexes trigger peristaltic waves, which facilitate transportation of indigestible substances such as bone, fiber, and foreign bodies from the stomach, through the small intestine, past the ileocecal sphincter, and into the colon.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 6
Correct
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In Hirschsprung disease which one is incorrect
Your Answer: Due to congenital absence of myenteric and submucosal plexuses
Explanation:During normal prenatal development, cells from the neural crest migrate into the large intestine (colon) to form the networks of nerves called the myenteric plexus (Auerbach plexus) (between the smooth muscle layers of the gastrointestinal tract wall) and the submucosal plexus (Meissner plexus) (within the submucosa of the gastrointestinal tract wall). In Hirschsprung’s disease, the migration is not complete and part of the colon lacks these nerve bodies that regulate the activity of the colon. The affected segment of the colon cannot relax and pass stool through the colon, creating an obstruction.
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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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Choose the correct statement regarding trabecular bone:
Your Answer: Receives nutrients from bone ECF
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.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 8
Incorrect
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A 30-year-old female was brought to the ER in a confused state. The patient works in a photograph development laboratory. On admission, she was hypoxic and hypotensive. A provisional diagnosis of cyanide poisoning was made. What is the definitive treatment?
Your Answer: Desferioxamine
Correct Answer: Hydroxocobalamin
Explanation:Cyanide poisoning: Aetiology:Smoke inhalation, suicidal ingestion, and industrial exposure (specific industrial processes involving cyanide include metal cleaning, reclaiming, or hardening; fumigation; electroplating; and photo processing) are the most frequent sources of cyanide poisoning. Treatment with sodium nitroprusside or long-term consumption of cyanide-containing foods is a possible source.Cyanide exposure most often occurs via inhalation or ingestion, but liquid cyanide can be absorbed through the skin or eyes. Once absorbed, cyanide enters the blood stream and is distributed rapidly to all organs and tissues in the body. Pathophysiology:Inside cells, cyanide attaches itself to ubiquitous metalloenzymes, rendering them inactive. Its principal toxicity results from inactivation of cytochrome oxidase (at cytochrome a3), thus uncoupling mitochondrial oxidative phosphorylation and inhibiting cellular respiration, even in the presence of adequate oxygen stores.Presentation:• ‘Classical’ features: brick-red skin, smell of bitter almonds• Acute: hypoxia, hypotension, headache, confusion• Chronic: ataxia, peripheral neuropathy, dermatitisManagement:• Supportive measures: 100% oxygen, ventilatory assistance in the form of intubation if required.• Definitive: Hydroxocobalamin (iv) is considered the drug of choice and is approved by the FDA for treating known or suspected cyanide poisoning. • Coadministration of sodium thiosulfate (through a separate line or sequentially) has been suggested to have a synergistic effect on detoxification.Mechanism of action of hydroxocobalamin: • Hydroxocobalamin combines with cyanide to form cyanocobalamin (vitamin B-12), which is renally cleared.• Alternatively, cyanocobalamin may dissociate from cyanide at a slow enough rate to allow for cyanide detoxification by the mitochondrial enzyme rhodanese.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 9
Correct
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The pathway responsible for the discriminative aspect of pain, is called the:
Your Answer: Neospinothalamic tract
Explanation:The spinothalamic tract is an ascending or a sensory tract, responsible for transmission of pain and temperature. The neospinothalamic tract is responsible for fast pain or discriminative pain whereas the palaeospinothalamic tract is responsible for transmission of slow pain.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 10
Incorrect
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Within the hypothalamus, the dopamine-secreting neurones of the intrahypothalamic system have their cell bodies in which nuclei?
Your Answer: Infraoptic
Correct Answer: Arcuate
Explanation:Arcuate nucleus dopaminergic neurons consist of a single group of neurons that project to the median eminence where they release dopamine into the hypophyseal portal circulation to inhibit pituitary prolactin secretion.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 11
Incorrect
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The primary auditory cortex is:
Your Answer: Brodmann area 42
Correct Answer: Brodmann area 41
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 12
Incorrect
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Which of the following would provide relief from nausea and vomiting?
Your Answer: Bromocriptine
Correct Answer: Cannabinoids
Explanation:Ondansetron, chlorpromazine and haloperidol are effective antiemetic agents. Corticosteroids, cannabinoids, and benzodiazepines, alone or in combination with 5-HT3 and D2 antagonists, are also useful in the treatment of vomiting produced by chemotherapy.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 13
Incorrect
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In liver failure there is likely to be?
Your Answer: Raised blood urea
Correct Answer: Bleeding disorders
Explanation:Liver failure can lead to several significant changes in the body’s physiology, but let’s review each option in the context of liver failure:
- Raised blood urea: This is not typical of liver failure. In liver failure, blood urea nitrogen (BUN) levels are often low because the liver is not effectively converting ammonia to urea.
- Increase in the albumin/globulin ratio in the blood: This is incorrect. In liver failure, albumin production decreases, leading to a lower albumin/globulin ratio.
- Bleeding disorders: This is possible, but it often fluctuates. Liver failure can lead to both bleeding tendencies due to decreased production of clotting factors and a hypercoagulable state due to the reduced synthesis of anticoagulant proteins like Protein C and S.
- Stable blood glucose level: This is incorrect. Liver failure often causes hypoglycemia because the liver’s ability to produce glucose via gluconeogenesis and glycogenolysis is impaired.
- Increased absorption of fat: This is incorrect. Liver failure can lead to decreased bile production, which is necessary for fat emulsification and absorption, resulting in decreased fat absorption.
Given these points, the most likely option related to liver failure would actually be issues related to bleeding complications.
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This question is part of the following fields:
- Hepatobiliary
- Medicine
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Question 14
Incorrect
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Which neurotransmitter is made from hydroxylation and decarboxylation of tryptophan?
Your Answer: Dopamine
Correct Answer: Serotonin
Explanation:Serotonin is synthesized from the essential amino acid tryptophan. The rate-limiting step is the conversion of the amino acid to 5-hydroxytryptophan by tryptophan hydroxylase. This is then converted to serotonin by the aromatic L-amino acid decarboxylase.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 15
Incorrect
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The following can cause steatorrhea except
Your Answer: Diseases of the distal ileum
Correct Answer: Diseases that destroy the endocrine portion of the pancreas
Explanation:Dietary fats and lipids are usually efficiently digested and over 90% absorbed. Impaired digestion or absorption can result in fatty stools. Possible causes include exocrine (not endocrine) pancreatic insufficiency, with poor digestion from lack of lipases, loss of bile salts, which reduces micelle formation, and small intestinal disease producing malabsorption. Various other causes including certain medicines that block fat absorption, or indigestible or excess oil/fat in diet.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 16
Incorrect
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What percentage of blood is supplied to the liver by the portal vein?
Your Answer: 45%
Correct Answer: 75%
Explanation:The portal vein supplies 75% of the blood to the liver and exceeds the arterial supply of the organ.
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This question is part of the following fields:
- Hepatobiliary
- Medicine
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Question 17
Incorrect
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Histamine, acetylcholine and gastrin act by way of which second messengers in the release of acid by parietal cells:
Your Answer: Camp
Correct Answer: A and D
Explanation:Acetylcholine, Histamine and Gastrin receptors are located on the basolateral membrane of the parietal cell and control its activity. Stimulation of these receptors modulates the levels of protein kinases in the cell and brings about the changes from a resting to stimulated structure. Protein kinase catalyses conversion of ATP to cyclic AMP which activates the proton pump. Calcium ions increase gastric acid secretion elicited by gastrin released through a vagal mechanism, and also by a direct effect on parietal cells.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 18
Incorrect
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Which intestinal cells play a major role in secretory immunity?
Your Answer: B cells
Correct Answer: M cells
Explanation:M cells are specialized epithelial cells of the MALT or mucosa-associated lymphoid tissues. They transport antigens from the intestinal lumen to cells of the immune system, thereby initiating an immune response. T and B cells are lymphocytes found in blood. Mucous cells secrete mucous and can be considered as a part of innate immunity. Chief cells in the gastric mucosa secret pepsin.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 19
Incorrect
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In Argyll Robertson pupils…
Your Answer: May be a sign of diabetic neuropathy
Correct 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 20
Incorrect
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The following is true about the carotid arterial supply to the brain:
Your Answer: The 6 most important branches arise prior to the circle of Willis
Correct Answer: Following carotid occlusion, precapillary anastomoses are unable to prevent infarction
Explanation:The brain has two sources of blood supply; the internal carotid arteries which are the anterior segment or the main artery that supplies the anterior portion of the brain, and the vertebral arteries which is the posterior segment which supplies the posterior portion of the brain. The internal carotid arteries branch and form two major arteries anterior and middle cerebral arteries. The right and left vertebral arteries fuse together at the level of the pons on the anterior surface of the brainstem to form the midline basilar artery. The basilar artery joins the blood supply from the internal carotids in an arterial ring at the base of the brain called the circle of Willis. The anterior and posterior communicating arteries conjoin the two major sources of cerebral vascular supply via the circle of Willis improving the chances of any region of the brain continuing to receive blood if one of the major arteries becomes occluded.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 21
Incorrect
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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 22
Incorrect
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Into how many functional units can the cerebellum be divided?
Your Answer: 5
Correct Answer: 3
Explanation:The functional division of the cerebellum are the: Vestibulocerebellum (floculonodular lobe), Spinocerebellum (vermis and associated areas in the midline) and cerebrocerebellum (lateral hemispheres).
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This question is part of the following fields:
- Medicine
- Neurology
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Question 23
Incorrect
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A lesion that interrupts one optic nerve causes blindness:
Your Answer: Bilateral, opposite sites of visual fields, in half of the visual fields (heteronymous hemianopia)
Correct Answer: In the eye on the same side as the optic nerve
Explanation:The optic nerve on each side contains medial and lateral fibers originating from the retina. Medial fibers cross at the optic chiasm and become the optic tract ending in the visual cortex of the occipital lobe. If there is a lesion interrupting the “optic nerve” on one side, the same side eye will be completely blind.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 24
Incorrect
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A 50-year-old farmer, under treatment for depression, presents to the emergency department following an intentional overdose of an unidentified substance. On examination, he was found to be bradycardic, hypotensive, hyper-salivating, and disoriented. On ocular examination, his pupils were found to be miotic. What is the most likely substance he ingested?
Your Answer: Paraquat
Correct 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 25
Correct
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A 23 year old male patient presents with urethritis for the last 2 weeks that has not responded to antibiotics. Lately he has developed an onset of new range of symptoms that are linked to his HLA B27 positivity. Which of the following signs is not related to Reiter's syndrome?
Your Answer: A mild fever with a generalised macular rash
Explanation:Reactive arthritis, (formerly known as Reiter’s syndrome), is an autoimmune condition that occurs after a bacterial infection of the gastrointestinal or urinary tract. It is categorized as a seronegative spondylarthritis because of its association with HLA-B27. Reactive arthritis primarily affects young men and usually presents with musculoskeletal or extra‑articular symptoms. The characteristic triad consists of arthritis, conjunctivitis, and urethritis. The diagnosis is based on clinical features such as patient history and physical examination; there are no specific tests for reactive arthritis. Treatment is primarily symptomatic and consists of the administration of NSAIDs, as most patients recover spontaneously. Dermatologic manifestations include skin lesions of the glans resembling psoriasis (balanitis circinata); hyperkeratinisation of the palms and soles (keratoderma blenorrhagicum)
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 26
Incorrect
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Sympathetic supply to the stomach is derived from
Your Answer: T5-T9 spinal segments via the superior mesenteric ganglion
Correct Answer: T5-T9 spinal segments via the coeliac ganglion
Explanation:Parasympathetic innervation to the stomach is from the vagus nerve and the sympathetic innervation is from the T5-T9 spinal segments via the coeliac ganglion through the greater splanchnic nerve.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 27
Incorrect
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Which of the following drugs have the best gram positive cover?
Your Answer:
Correct Answer: Glycopeptides
Explanation:Cephalosporin has a mixed coverage of gram positive and negative organisms. Aminoglycosides are active against gram negative aerobic bacteria. Quinolones mainly cover gram negative bacteria. Monobactams primarily cover infections caused by gram negative bacteria. Glycopeptides are antibiotics effective primarily against gram positive cocci.
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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Question 28
Incorrect
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Question 29
Incorrect
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In RFLP (restriction fragment length polymorphism), the DNA fragments are separated by length through a process known as:
Your Answer:
Correct Answer: Agarose gel electrophoresis
Explanation:Samples of DNA from individuals are broken into pieces by restriction enzymes and the fragments are separated according to their lengths via gel electrophoresis. Although now largely obsolete due to the rise of inexpensive DNA sequencing technologies, RFLP analysis was the first DNA profiling technique inexpensive enough to see widespread application.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 30
Incorrect
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Glucose is typically removed from the urine by…?
Your Answer:
Correct Answer: Secondary active transport
Explanation:Glucose, amino acids, inorganic phosphate, and some other solutes are resorbed via secondary active transport through co-transporters driven by the sodium gradient out of the nephron.
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This question is part of the following fields:
- Medicine
- Renal
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Question 31
Incorrect
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Question 32
Incorrect
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Which of the following has the shortest duration:
Your Answer:
Correct Answer: Atrial systole
Explanation:Atrial systole: 0.1s
Atrial diastole: around 0.4s
Ventricular diastole: 0.4-0.53s
Ventricular systole: 0.27s
PR interval: 0.12-0.2 s
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 33
Incorrect
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The following is true of the sinus node:
Your Answer:
Correct Answer: It generates impulses automatically & at a quicker rate than other cardiac cells
Explanation:The SA node exhibits automaticity. It generates the impulses to which the heart beats. It fires at a faster speed than the rest of the nervous components of the heart i.e. the AV nodes, purkinje fibers. This is the reason when the SA node fails the heart beats to the rhythm of the AV node.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 34
Incorrect
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Bronchial smooth muscle:
Your Answer:
Correct Answer: Tone is increased by cholinergic discharge
Explanation:The lungs are supplied by both the sympathetic and parasympathetic divisions of the autonomic nervous system. The parasympathetic innervation is supplied by the vagus nerve. The parasympathetic nervous system is the dominant neuronal pathway in the control of airway smooth muscle tone. Stimulation of cholinergic nerves causes bronchoconstriction, mucus secretion, and bronchial vasodilation. Sympathetic innervation is supplied by the T1 to T5 of the spinal cord and act mainly via beta adrenergic receptors. Stimulation of the sympathetic nervous system causes vasoconstriction and bronchodilation.
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This question is part of the following fields:
- Medicine
- Respiratory
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Question 35
Incorrect
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Vitamin B12 is transported from the enterocytes to the bone marrow by which factor?
Your Answer:
Correct Answer: Transcobalamin II (TC IIi)
Explanation:B12 must be attached to 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. Once the IF/B12 complex is recognized by specialized ileal receptors, it is transported into the portal circulation. The vitamin is then transferred to transcobalamin II (TC-II/B12), which serves as the plasma transporter.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 36
Incorrect
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Which of the following statements regarding influenza virus is correct?
Your Answer:
Correct Answer: Influenza is a RNA virus
Explanation:The Orthomyxoviruses are a family of RNA viruses that includes six genera: Influenza virus A, Influenza virus B, Influenza virus C, Isavirus, Thogotovirus and Quaranjavirus.The mechanism of the evolutionary force of antigenic shift allows influenza viruses to exchange genes with strains that infect different species. Under this mechanism, a human influenza virus could exchange genes with an avian strain, and that is how pandemic strains arise.
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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Question 37
Incorrect
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Where is angiotensinogen produced?
Your Answer:
Correct Answer: Liver
Explanation:Angiotensin is a peptide hormone that causes vasoconstriction and a subsequent increase in blood pressure. Angiotensin also stimulates the release of aldosterone from the adrenal cortex. Aldosterone promotes sodium retention in the distal nephron, in the kidney, which also drives blood pressure up. It is derived from the precursor molecule angiotensinogen, a serum globulin produced in the liver.
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This question is part of the following fields:
- Medicine
- Renal
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Question 38
Incorrect
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Which of the following affects the magnitude of the action potential?
Your Answer:
Correct Answer: Changes in the external Na+ concentration
Explanation:The magnitude of the action potential is determined by the sodium current. Increase in external sodium will result in increased influx of sodium and hence generation of a stronger action potential.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 39
Incorrect
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Which enzyme deficiency causes Beriberi?
Your Answer:
Correct Answer: Thiamine
Explanation:Beriberi refers to a cluster of symptoms caused primarily by thiamine (vitamin B1) deficiency. Symptoms of beriberi include weight loss, emotional disturbances, impaired sensory perception, weakness and pain in the limbs, and periods of irregular heart rate.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 40
Incorrect
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The conversion of fructose to fructose 1-phosphate is catalysed by:
Your Answer:
Correct Answer: Fructokinase
Explanation:The first step in the metabolism of fructose is the phosphorylation of fructose to fructose 1-phosphate by fructokinase.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 41
Incorrect
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The cells that secrete HCL are found in which part of the stomach?
Your Answer:
Correct Answer: Body
Explanation:The stomach can be divided in to different regions. Cardia, fundus, body, antrum and pylorus from proximal end to distal end respectively. Different cell types are distributed accordingly among the regions of the stomach. Cells that secret HCl in the gastric mucosa are known as parietal cells and are abundant in the gastric body region. They have receptors for acetylcholine stimulated via the vagus nerve, histamine receptors and gastrin receptors which stimulate gastric acid secretion. G cells that secret gastrin are abundant in the antrum.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 42
Incorrect
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The process whereby bacterial products interact with plasma factors and cells to produce agents that attract neutrophils to an infected area is called:
Your Answer:
Correct Answer: Chemotaxis
Explanation:During an inflammatory process many cytokines are produced that act as chemokines to attract neutrophils to the site of inflammation. These include bacterial products, IL-8, C5a and LTB4.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 43
Incorrect
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The predominant site in the lymph node where T lymphocytes are found is:
Your Answer:
Correct Answer: Paracortex
Explanation:Paracortex is found between the cortex and the medulla and it is composed of a non-nodular type of arrangement that is mostly made up of T cells.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 44
Incorrect
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Question 45
Incorrect
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Which of the following is NOT a cause of onycholysis?
Your Answer:
Correct Answer: Mycoplasma pneumonia
Explanation:Onycholysis is the separation of the distal edge of the nail from the vascular nailbed causing whiteness of the free edge. Causes include:- Idiopathic- Trauma, excessive manicuring- Infection: especially fungal- Skin disease: psoriasis, dermatitis- Impaired peripheral circulation e.g. Raynaud’s- Systemic disease: hyper/hypothyroidism, reactive arthritis, porphyria cutanea tarda- Sometimes a reaction to detergents (e.g. washing dishes with bare hands, using detergent-based shampoos or soaps).- Patients with hepatocellular dysfunction may develop hair-thinning or hair loss and nail changes such as clubbing, leukonychia (whitening), or onycholysis.
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This question is part of the following fields:
- Dermatology
- Medicine
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Question 46
Incorrect
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Amongst the following cells, which is responsible for the secretion of defensins?
Your Answer:
Correct Answer: Neutrophils
Explanation:Eosinophils are phagocytic and they are directed against helminths. Basophils are involved in allergic reactions and contain histamine and vasoactive granules in their cytoplasm. Mast cells are similar to basophils. Monocytes differentiate into macrophages in the tissue, secret interleukins and are phagocytic. Neutrophils are phagocytic but are also responsible for secreting defensins.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 47
Incorrect
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Where in the course of the gastrointestinal tract does the first significant digestion of fat begin in a normal human being?
Your Answer:
Correct Answer: Duodenum
Explanation:The enzyme lipase which is responsible for digestion of fat is secreted by the exocrine pancreas in the 2nd part of the duodenum at the point where the pancreatic duct opens. It opens together with the common bile duct which contains bile that emulsify fat aiding in digestion. The oesophagus, stomach and mouth do not contain enzymes related to fat digestion.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 48
Incorrect
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Transport of Iron into enterocytes occurs via which membrane transporter?
Your Answer:
Correct Answer: Divalent metal transporter 1(dmt1)
Explanation:To be absorbed, dietary iron can be absorbed as part of a protein such as haem protein or iron must be in its ferrous Fe2+ form. A ferric reductase enzyme on the enterocytes’ brush border, duodenal cytochrome B (Dcytb), reduces ferric Fe3+ to Fe2+. A protein called divalent metal transporter 1 (DMT1), which can transport several divalent metals across the plasma membrane, then transports iron across the enterocyte’s cell membrane into the cell.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 49
Incorrect
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Question 50
Incorrect
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In the menstrual cycle, ovulation is triggered by:
Your Answer:
Correct Answer: A pituitary LH surge due to the positive feedback effect of circulating oestrogens
Explanation:FSH and LH are secreted to start the development of a follicle at the start of each menstrual cycle. A surge in oestrogen causes a positive feedback in the LH cells of the pituitary; this causes ovulation.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 51
Incorrect
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Which heart sounds are matched correctly?
Your Answer:
Correct Answer: All of the above
Explanation:In healthy adults, there are two normal heart sounds often described as a lub and a dub (or dup), that occur in sequence with each heartbeat. These are the first heart sound (S1) and second heart sound (S2), produced by the closing of the atrioventricular valves and semilunar valves, respectively. In addition to these normal sounds, a variety of other sounds may be present including heart murmurs, adventitious sounds, and gallop rhythms S3 and S4. S3 is thought to be caused by the oscillation of blood back and forth between the walls of the ventricles initiated by blood rushing in from the atria. The reason the third heart sound does not occur until the middle third of diastole is probably that during the early part of diastole, the ventricles are not filled sufficiently to create enough tension for reverberation. S4 when audible in an adult is called a presystolic gallop or atrial gallop. This gallop is produced by the sound of blood being forced into a stiff or hypertrophic ventricle.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 52
Incorrect
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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.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 53
Incorrect
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Following an action potential, cytosolic Ca2+ is increased. The binding of free Ca2+ to troponin C results in all of the following except:
Your Answer:
Correct Answer: Weakening of the troponin i interaction with actin
Explanation:At rest, troponin i is bound to actin and tropomyosin and covers the site where the myosin head interacts with actin. When Calcium enters into the muscle, it binds with troponin C and cause a structural change in troponin i which moves out of the myosin binding site and causes the cross bridges between the actin and myosin filaments to occur.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 54
Incorrect
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An 81 year old male patient was admitted after an ischaemic stroke. Physical examination reveals left hemiparesis. How would you classify this hemiparesis based on the WHO International Classification of Functioning, Disability and Health?
Your Answer:
Correct Answer: Impairment of body function
Explanation:Symptoms and signs are classified as ‘impairment of body function’. The types of impairment classified as ‘activity limitation’ include difficulties that a patient may have in executing certain activities. The type of impairment classified as ‘participation restriction’ are problems a patient may have in social roles. The type of impairment classified as ‘pathology’ would be the diagnosis/disease. Right total anterior circulation infarct relates to the Oxford Bamford classification for stroke.
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This question is part of the following fields:
- Geriatrics
- Medicine
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Question 55
Incorrect
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What is the function of the BK channel on the vascular smooth muscle membrane?
Your Answer:
Correct Answer: Massive K+ efflux, increasing membrane potential, and shutting off the voltage gated Ca2+ channel
Explanation:BK channels, also known as large-conductance calcium-activated potassium channels, play a critical role in regulating vascular smooth muscle tone. When BK channels open, they allow a large efflux of potassium ions (K+) out of the cell. This efflux of K+ causes the membrane potential to become more negative (hyperpolarization), which in turn leads to the closure of voltage-gated calcium channels. The closure of these calcium channels reduces the influx of calcium ions (Ca2+) into the smooth muscle cells, resulting in decreased intracellular calcium levels and subsequent relaxation of the smooth muscle.
Thus, BK channels promote smooth muscle relaxation by hyperpolarizing the membrane and reducing the activity of voltage-gated Ca2+ channels.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 56
Incorrect
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What is the function of the pro-apoptotic Bcl-2 family of proteins, Bax and Bak?
Your Answer:
Correct Answer: Form permissive pores in the mitochondrial membrane
Explanation:The pro-apoptotic proteins in the BCL-2 family, including Bax and Bak, normally act on the mitochondrial membrane to promote permeabilization and release of cytochrome C and ROS, that are important signals in the apoptosis cascade. Growing evidence suggests that activated BAX and/or Bak form an oligomeric pore, MAC in the mitochondrial outer membrane. This results in the release of cytochrome c and other pro-apoptotic factors from the mitochondria, often referred to as mitochondrial outer membrane permeabilization, leading to activation of caspases.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 57
Incorrect
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Which ventral (motor) root is responsible for triceps?
Your Answer:
Correct Answer: C7
Explanation:Of the nerve fibers that make up the brachial plexus, C7 mainly forms the radial nerve to innervate the triceps muscle, thus innervating the shoulders, elbow, wrist and hand. C7 is responsible for the triceps reflex.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 58
Incorrect
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AV valves open during?
Your Answer:
Correct Answer: Early diastole
Explanation:The cardiac cycle refers to a complete heartbeat from its generation to the beginning of the next beat, and so includes the diastole, the systole, and the intervening pause.The first stage, diastole, is when the semilunar valves (the pulmonary valve and the aortic valve) close, the atrioventricular (AV) valves (the mitral valve and the tricuspid valve) open, and the whole heart is relaxed. The second stage, atrial systole, is when the atrium contracts, and blood flows from atrium to the ventricle.The third stage, isovolumic contraction is when the ventricles begin to contract, the AV and semilunar valves close, and there is no change in volume. The fourth stage, ventricular ejection, is when the ventricles are contracting and emptying, and the semilunar valves are open. During the fifth stage, isovolumic relaxation time, pressure decreases, no blood enters the ventricles, the ventricles stop contracting and begin to relax, and the semilunar valves close due to the pressure of blood in the aorta.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 59
Incorrect
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What is the effect of oxytocin on the breast?
Your Answer:
Correct Answer: Milk ejection
Explanation:Oxytocin is a peptide hormone and neuropeptide, produced by the hypothalamus and released by the posterior pituitary. It causes the milk ejection or let-down reflex, causing the milk to be transported to the subareolar sinuses, allowing it to be released through the nipple. This response is initiated by the act of suckling by the baby, but it can be conditioned to be triggered by different stimuli.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 60
Incorrect
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Which of the following vitamin deficiencies is associated with xerophthalmia?
Your Answer:
Correct Answer: Vitamin A
Explanation:Xerophthalmia caused by a severe vitamin A deficiency is described by pathologic dryness of the conjunctiva and cornea. The conjunctiva becomes dry, thick and wrinkled. If untreated, it can lead to corneal ulceration and ultimately to blindness as a result of corneal damage.
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This question is part of the following fields:
- Haematology
- Medicine
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SESSION STATS - PERFORMANCE PER SPECIALTY
