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Question 1
Incorrect
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Cells responsible for completely renewing the epithelium of the intestine are located:
Your Answer: At the base of the microvilli
Correct Answer: At the base of the crypts
Explanation:Epithelial cells are renewed every 4-5 days through a process of renewal and migration. Renewal relies on proliferative cells or stem cells that reside at the crypt base of the intestinal glands. Crypts are epithelial invasions into the underlying connective tissue.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 2
Correct
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What are the major motor proteins that interact with microtubules?
Your Answer: Kinesin and dynein
Explanation:The major motor proteins that interact with microtubules are kinesin, which usually moves toward the (+) end of the microtubule, and dynein, which moves toward the (−) end.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 3
Incorrect
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Wernicke’s area:
Your Answer: Is concerned with fine tuning detailed and coordinated patterns for vocalization
Correct Answer: Is concerned with comprehension of auditory and visual information
Explanation:Wernicke’s area is located in the categorical hemisphere or left hemisphere in about 95% of right handed individuals and 60% of left handed individuals. It is involved in the comprehension or understanding of written and spoken language. In contrast Broca’s area is involved in production of language.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 4
Incorrect
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The cells that secrete pepsinogen and gastric lipase are found in which part of the stomach?
Your Answer: Antrum
Correct Answer: Body and fundus
Explanation:Stomach can be divided in to different regions. Cardia, fundus, body, antrum and pylorus from proximal end to distal end respectively. Cells that secret the inactive form of pepsin or pepsinogen are chief cells and are abundant in the body (corpus) and the fundus region of the stomach.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 5
Incorrect
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Where would one find pericytes around endothelial cells?
Your Answer: Pre-capillary venules
Correct Answer: Post-capillary venules
Explanation:Pericytes release a wide variety of vasoactive agents which regulate the flow through the junction between endothelial cells.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 6
Correct
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Choose the correct answer: The cerebrocerebellum…
Your Answer: All options are correct
Explanation:Cerebrocerebellum is comprised of two lateral regions, the cerebellar hemispheres and communicates with the cerebral cortex. It is principally responsible for controlling coordination of movement. Three fiber bundles carry the input and output of the cerebellum. There are three cerebellar peduncles with different connections and functions. The three are mainly, superior, middle and inferior. The superior cerebellar peduncle is also known as the “Brachium conjunctivum”. It predominantly contains efferent fibers from the cerebellar nuclei, as well as some afferents from the spinocerebellar tract. The efferent pathways include cerebellorubral, dentatothalamic, and fastigioreticular fibers. These are tracts projecting from the deep cerebellar nuclei to the thalamus and red nucleus. The middle cerebellar peduncle connects to the pontine nucleus and the dorsal spinocerebellar tracts run through the superior cerebellar peduncle
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This question is part of the following fields:
- Medicine
- Neurology
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Question 7
Correct
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Which mechanism of action does Penicillin use?
Your Answer: Inhibit cell wall synthesis
Explanation:Bacteria constantly remodel their peptidoglycan cell walls, simultaneously building and breaking down portions of the cell wall as they grow and divide. β-Lactam antibiotics inhibit the formation of peptidoglycan cross-links in the bacterial cell wall; this is achieved through binding of the four-membered β-lactam ring of penicillin to the enzyme DD-transpeptidase. As a consequence, DD-transpeptidase cannot catalyse formation of these cross-links, and an imbalance between cell wall production and degradation develops, causing the cell to rapidly die.
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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Question 8
Incorrect
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Absorption of protein antigens i.e. bacterial and viral proteins takes place in the:
Your Answer: Mucosa-associated lymphoid tissue
Correct Answer: Microfold cells (m cells) of the intestine
Explanation:M cells are specialized epithelial cells. They have a high capacity of transcytosis of microorganisms and macromolecules. They rapidly uptake antigens and present them to immune cells associated with the gut. In contrast to absorptive enterocytes, M cells do not exert direct defence mechanisms to antigens and pathogens in the intestinal cavity. Crypts of Lieberkühn are located mainly in the small intestine and large intestine and the main function is to replenish epithelial cells and to secrete intestinal enzymatic juice as well as mucous. Brunner’s glands empty into intestinal glands and their main function is to secrete mucin and to form a protective mucus layer on the duodenal epithelial cells to protect it from acidic chyme coming from the stomach. Islets of Langerhans are located in the pancreas and secrets insulin mainly. Mucosa associated lymphoid tissue plays a role in inducing immune response after presentation of antigens.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 9
Correct
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Closure of the tricuspid valve is marked by which of the following features of the jugular venous waveform?
Your Answer: c wave
Explanation:The jugular venous pressure (JVP) classically has three upward deflections and two downward deflections. The upward deflections are the a (atrial contraction), c (ventricular contraction and resulting bulging of tricuspid into the right atrium during isovolumetric systole) and v = venous filling. The downward deflections of the wave are the x (the atrium relaxes and the tricuspid valve moves downward) and the y descent (filling of ventricle after tricuspid opening).
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 10
Correct
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A 32 year old male who has recently returned from a trip to Thailand presents with congestion of eyes and swelling of the knee joint. He completed a course of antibiotics for dysentery 4 weeks back. He experiences no dysuria and urine examination is normal. Which further information would be most useful in establishing a diagnosis?
Your Answer: History and physical examination
Explanation:The patient most likely has reactive arthritis which is usually diagnosed on history and clinical examination. The classic triad of symptoms include conjunctivitis, urethritis and arthritis. Arthritis and conjunctivitis may occur 4-6 weeks after a gastrointestinal or genitourinary infection. Arthritis usually occurs acutely, mostly involving the lower limb and is asymmetrical. Blood culture, urine culture and arthrocentesis (joint aspiration) will not yield positive results.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 11
Correct
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Which part of the cerebellum is primarily responsible for interacting with the motor cortex and planning and programming movements?
Your Answer: Cerebrocerebellum
Explanation:The cerebrocerebellum is the largest functional subdivision of the cerebellum, comprising of the lateral hemispheres and the dentate nuclei. It is involved in the planning and timing of movements, and in the cognitive functions of the cerebellum.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 12
Correct
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The function of ATP in cardiac muscle contraction includes:
Your Answer: Binding to myosin after the power stroke to allow uncoupling of actin and myosin
Explanation:After calcium binds to the troponin C, there is a conformational change in the structure of troponin I and tropomyosin, which moves out of the way and frees the site where myosin can bind to actin. This results in the formation of the cross linkage of the actin and myosin giving rise to the power stroke in the contraction phase. This occurs with the release of ADP. When ATP combines to this complex it breaks and the cycle repeats itself.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 13
Correct
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Question 14
Correct
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Where would one normally find venous valves?
Your Answer: Saphenous vein
Explanation:The intima of the limb veins is folded at intervals to form venous valves that prevent retrograde flow. There are no valves present in the very small veins, the great veins, or the veins in the brain and viscera.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 15
Correct
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Which two ducts form the ampulla of Vater?
Your Answer: The common bile duct and the pancreatic duct of Wirsung
Explanation:The ampulla of Vater, also known as the hepatopancreatic ampulla or the hepatopancreatic duct, is formed by the union of the pancreatic duct and the common bile duct. The ampulla is specifically located at the major duodenal papilla.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 16
Correct
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The following are examples of the functions of the vascular endothelium except:
Your Answer: Tumour suppression
Explanation:Vascular endothelium has many important functions including regulation of vascular tone, molecular exchange between blood and tissue compartments, hemostasis and signaling for the immune regulation and inflammation. Depending on specific tissue needs and local stresses, endothelial cells are capable of evoking either antithrombotic or prothrombotic events. Tumor suppression is related to genes, or anti-oncogenes, that regulate a cell during cell division and replication.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 17
Incorrect
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Which of the following statements is true of the beta- lactams:
Your Answer: May produce a hypersensitivity rash in up to 60% of patients with infectious mononucleosis
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 18
Incorrect
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The triangle with the heart at its centre, using limb leads is called:
Your Answer: Duke
Correct Answer: Einthoven
Explanation:The Einthoven triangle is formed by placing the limb leads on both the arms and on the left leg with the heart in the centre.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 19
Incorrect
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In Starling’s law of the heart, the decrease in tension developed by muscle contraction at high degrees of stretch is due to:
Your Answer: A decrease in the number of cross bridges between myosin and actin
Correct Answer: Disruption of myocardial fibers
Explanation:Starling law states that the force of contraction is directly proportional to the preload. When the heart muscle is stretched beyond its limit the tension that is developed decreases, this is not due to loss of formation of effective myosin and actin cross bridges. The heart muscles despite being fully stretched is never stretched to this point. The reason for this decreased tension is physical disruption of the myocardial fibers.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 20
Incorrect
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Which vitamin plays a major role in the metabolism of many amino acids?
Your Answer: Vitamin B3
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 21
Incorrect
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Select the CORRECT statement regarding bile salts…
Your Answer: Are derived from amino acids.
Correct Answer: Are necessary for any bile acid secretion by hepatocytes.
Explanation:Bile salts stimulate bile secretion by the liver. Bile salts do not have an enzymatic action on digestion of fat but rather emulsify fat for the action of enzymes secreted mainly by the pancreas. Bile salts are polar cholesterol derivatives and are not derived from amino acids.
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This question is part of the following fields:
- Hepatobiliary
- Medicine
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Question 22
Incorrect
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Which of the following statements is the most characteristic of primary Raynaud's phenomena?
Your Answer: More common in middle aged females
Correct Answer: Fingers are symmetrically involved during an attack
Explanation:A typical attack may last less than an hour but can also persist for longer. In primary Raynaud’s, attacks are more likely symmetric, episodic, and without evidence of peripheral vascular disease. Patients more commonly have a negative ANA and normal inflammatory markers. There should be no evidence of tissue gangrene, digital pitting, or tissue injury in primary Raynaud’s. In contrast, patients with secondary Raynaud’s will describe attacks that are more frequent, painful, often asymmetric and may lead to digital ulcerations.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 23
Incorrect
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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 24
Incorrect
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Where do the portal hypophysial vessels arise?
Your Answer: Arcuate nucleus
Correct Answer: Median eminence
Explanation:The hypothalamic-hypophysial portal system connects the brain to the anterior pituitary. It is made up of two capillary beds, one in the median eminence and the other in the anterior pituitary. Blood from the plexus of the median eminence is carried by portal veins, draining into the cavernous and posterior intercavernous sinuses. This system delivers hypothalamic hormones to their target cells.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 25
Correct
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The collection of genes that are termed the major histocompatibility complex (MHC) are found on:
Your Answer: Short arm of chromosome 6
Explanation:Histocompatibility, or tissue compatibility, is the property of having the same, or sufficiently similar, alleles of a set of genes called human leukocyte antigens (HLA). HLA is the human form of the major histocompatibility complex (MHC) genes found in all vertebrates. On a population level there is a great number of different alleles at each HLA locus on the short arm of chromosome 6
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This question is part of the following fields:
- Immunology
- Medicine
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Question 26
Incorrect
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ADH causes?
Your Answer: Upregulates aquaporin 1
Correct Answer: Increased permeability of the collecting ducts to water
Explanation:Vasopressin (ADH) has three main effects:1. Increasing the water permeability of distal convoluted tubule and collecting duct cells in the kidney, thus allowing water reabsorption and excretion of more concentrated urine.2. Increasing permeability of the inner medullary portion of the collecting duct to urea by regulating the cell surface expression of urea transporters.3. Acute increase of sodium absorption across the ascending loop of Henle.
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This question is part of the following fields:
- Medicine
- Renal
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Question 27
Correct
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90% of erythropoietin necessary for haemopoesis is produced by the kidneys, the remainder is formed in the?
Your 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 28
Incorrect
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Regarding Gene Knockout Mouse Models, all are true except:
Your Answer: RFLP analysis is slow and cumbersome and is now largely obsolete
Correct Answer: In knockout mouse models a gene is turned on through targeted mutation
Explanation:In knockout mouse models, a gene is not turned on but rather turned off or “knocked out” through targeted mutation. This involves disrupting or deleting the gene to study the effects of its loss of function. Knockout models are crucial for understanding the roles of specific genes, particularly those with unknown functions.
The other statements are true:
- Knockout models are important in studying the roles of sequenced genes with unknown function.
- RFLP (Restriction Fragment Length Polymorphisms) can be subcategorized as SLP (single locus probe) and MLP (multi locus probe).
- RFLP analysis is slow and cumbersome and is now largely obsolete, having been replaced by more efficient techniques.
- Sequence changes involved in RFLP can be analyzed more quickly by PCR (Polymerase Chain Reaction).
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This question is part of the following fields:
- Genetics
- Medicine
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Question 29
Correct
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Where is the majority of Mg2+ absorbed?
Your Answer: Thick ascending limb of loop of Henle.
Explanation:Although the majority of the filtered magnesium is reabsorbed within the ascending loop of Henle, it is now recognized that the distal tubule also plays an important role in magnesium conservation.
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This question is part of the following fields:
- Medicine
- Renal
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Question 30
Correct
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Which of the following is true of the Natriuretic hormones?
Your Answer: They are released in response to hypervolemia
Explanation:Natriuretic hormones are vasodilators released in response to hypervolemia.
Natriuretic hormones (NH) include three groups of compounds: the natriuretic peptides NPs (ANP, BNP and CNP), the gastrointestinal peptides (guanylin and uroguanylin), and endogenous cardiac steroids. These substances induce the kidney to excrete sodium and therefore participate in the regulation of sodium and water homeostasis, blood volume, and blood pressure (BP). In addition to their peripheral functions, these hormones act as neurotransmitters or neuromodulators in the brain.
Atrial natriuretic peptide (ANP) plays a crucial role in blood pressure regulation by inducing natriuresis and diuresis in the kidney, inhibiting renin secretion, aldosterone production, and promoting vasorelaxation. Two paracrine factors derived from endothelial cells play important roles in modulating ANP secretion. Endothelin, a potent vasoconstrictor, stimulates ANP secretion and augments stretch induced ANP secretion. The dramatic increase in ANP release produced by cardiac ischemia appears to be mediated in part by endothelin. Nitric oxide (NO), an important vasodilator, is also produced by endothelial cells and inhibits ANP secretion.
Brain natriuretic peptide (BNP) shares ANP’s receptor but is primarily associated with antifibrotic effects in ventricular remodeling, serving as a biomarker for heart failure and myocardial infarction.
C-type natriuretic peptide (CNP) acts locally in an autocrine/paracrine manner, exerting potent cardiovascular effects, including vasorelaxation and vascular remodeling post-injury. NPs also demonstrate diverse effects beyond cardiovascular and renal systems, such as bronchodilation, anti-inflammatory actions, and metabolic effects on adipose tissue and long bones.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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