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Question 1
Correct
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A 35-year-old woman under treatment for long-term epilepsy with valproate presented with complaints of excessive weight gain. She is consuming oral contraceptive pills.Which among the following is the best alternative to valproate for treating long-term epilepsy?
Your Answer: Lamotrigine
Explanation:Among the given anti-epileptics the best drug that can be given in this patient is lamotrigine.Topiramate, carbamazepine, phenytoin, and phenobarbital are all hepatic enzyme inducers and are associated with decreased effectiveness of the oral contraceptive (OCP) due to acceleration of the metabolism of oestrogens and progestogens.If she is planning on pregnancy then registry studies suggest that lamotrigine would also be the best choice.Other hepatic enzyme inducers include rifampicin, spironolactone, griseofulvin, etc.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 2
Incorrect
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A 22-year-old female comes to you for counselling regarding the initiation of combined oral contraceptive pill. Which of the following statements is correct?
Your Answer:
Correct Answer: She will still be protected against pregnancy if she takes amoxicillin for a lower respiratory tract infection while on the combined pill
Explanation:The true statement among the given options is that she will still be protected against pregnancy if she takes amoxicillin for a lower respiratory tract infection while on the combined pill.Other than enzyme-inducing antibiotics such as rifampicin, antibiotics do not reduce the efficacy of the combined oral contraceptive pill.It was previously advised that barrier methods of contraception should be used if taking an antibiotic while using the contraceptive pill, due to concerns that antibiotics might reduce the absorption of the pill. This is now known to be untrue. However, if the absorptive ability of the gut is compromised for another reason, such as severe diarrhoea or vomiting, or bowel disease, this may affect the efficacy of the pill.The exception to the antibiotic rule is that hepatic enzyme-inducing antibiotics such as rifampicin and rifaximin do reduce the efficacy of the pill. Other enzyme-inducing drugs, such as phenytoin, phenobarbital, carbamazepine or St John’s Wort can also reduce the effectiveness of the pill.Other options:The combined pill is often prescribed for women with heavy periods as it can make them lighter and less painful. There is no evidence that women on the combined pill put on any significant weight, although they may experience bloating at certain times in the course. Women on the pill require monitoring of their blood pressure. There are multiple different types of combined pills.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 3
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 4
Incorrect
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A 65-year-old man presents to you three weeks after initiating metformin for type 2 diabetes mellitus. His body mass index is 27.5 kg/m^2. At a dose of 500mg TDS the patient has experienced significant diarrhoea. Even on reducing the dose to 500mg BD his symptoms persisted. What is the most appropriate next step in this patient?
Your Answer:
Correct Answer: Start modified release metformin 500mg od with evening meal
Explanation:Here, the patient seems to be intolerant to standard metformin. In such cases, modified-release preparations is considered as the most appropriate next step. There is some evidence that these produce fewer gastrointestinal side-effects in patients intolerant of standard-release metformin.Metformin is a biguanide and reduces blood glucose levels by decreasing the production of glucose in the liver, decreasing intestinal absorption and increasing insulin sensitivity. Metformin decreases both the basal and postprandial blood glucose.Other uses: In Polycystic Ovarian Syndrome (PCOS), Metformin decreases insulin levels, which then decreases luteinizing hormone and androgen levels. Thus acting to normalize the menstruation cycle.Note:Metformin is contraindicated in patients with severe renal dysfunction, which is defined as a glomerular filtration rate (GFR) less than 30 ml/min/1.732m2. Metformin overdose has been associated with hypoglycaemia and lactic acidosis, for this reason, it has a black box warning for lactic acidosis.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 5
Incorrect
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Neurogenesis occurs throughout life in the following two areas:
Your Answer:
Correct Answer: Hippocampus and striatum
Explanation:In humans, neurogenesis or new neurons are continually born during adulthood in two regions of the brain: The subgranular zone (SGZ), part of the dentate gyrus of the hippocampus and the striatum. In other species of mammals, adult-born neurons also appear in the olfactory bulb. In humans, however, few if any olfactory bulb neurons are generated after birth.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 6
Incorrect
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In most somatic cells telomeres progressively shorten as:
Your Answer:
Correct Answer: The cell divides
Explanation:Telomere length shortens with age. Progressive shortening of telomeres leads to senescence, apoptosis, or oncogenic transformation of somatic cells, affecting the health and lifespan of an individual. 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.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 7
Incorrect
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What is the rationale concerning the use of sodium cromoglycate in the prophylaxis of bronchial asthma?
Your Answer:
Correct Answer: Inhibition of mast-cell degranulation
Explanation:Sodium cromoglycate principally acts by inhibiting the degranulation of mast cells triggered by the interaction of antigen and IgE. The inhibitory effect on mast cells appears to be cell-type specific since cromoglycate has little inhibitory effect on mediator release from human basophils.Thus, it inhibits the release of histamine, leukotrienes, and slow-reacting substance of anaphylaxis from mast cells by inhibiting degranulation following exposure to reactive antigens.Adverse effects include cough, flushing, palpitation, chest pain, nasal congestion, nausea, fatigue, migraine, etc.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 8
Incorrect
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Which of the following substances is involved in the respiratory burst by the neutrophil?
Your Answer:
Correct Answer: NADPh oxidase
Explanation:The respiratory burst is a rapid release of reactive oxygen species (ROS) from neutrophils and other phagocytes. This process is crucial for the destruction of pathogens. The key components and enzymes involved in the respiratory burst include:
- NADPH oxidase: This enzyme complex plays a central role in the respiratory burst by converting oxygen (O2) into superoxide anion (O2•-), a reactive oxygen species. This is the initial step in the production of various ROS.
- Superoxide dismutase (SOD): This enzyme converts superoxide anion (O2•-) into hydrogen peroxide (H2O2). While SOD is involved in the pathway, the respiratory burst is initiated by NADPH oxidase.
- Myeloperoxidase (MPO): This enzyme uses hydrogen peroxide (H2O2) to produce hypochlorous acid (HOCl) from chloride ions (Cl-), which is a potent antimicrobial agent. Myeloperoxidase also produces other reactive species using halide ions.
- Catalase: This enzyme degrades hydrogen peroxide (H2O2) into water (H2O) and oxygen (O2). While catalase helps to protect the cell from oxidative damage by breaking down H2O2, it is not involved in the generation of ROS during the respiratory burst.
- Adenylate cyclase: This enzyme is involved in the production of cyclic AMP (cAMP) from ATP and is not directly related to the respiratory burst.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 9
Incorrect
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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.
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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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Pendrin is a Cl-/I- exchanger whose function is:
Your Answer:
Correct Answer: Transfer of iodide across the thyrocyte apical membrane into the colloid
Explanation:Pendrin is an anion transporter present in the inner ear, thyroid and kidney. It regulates the entrance of iodide from the thyroid cell to the colloid space. It has been proposed that its role could be the maintenance of the ionic composition of the endolymph.
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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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Adrenergic stimulation will lead to myocyte relaxation via the following mechanisms
Your Answer:
Correct Answer: Increased phosphorylation of phosholamban
Explanation:Phosphorylation of phospholamban, which increases calcium ATPase activity and sequestration of calcium in the sarcoplasmic reticulum. An increased rate of relaxation is explained because cAMP also activates the protein phospholamban, situated on the membrane of the SR, that controls the rate of uptake of calcium into the SR. The latter effect explains enhanced relaxation (lusitropic effect).
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 12
Incorrect
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Bile acids will be prevented from being absorbed by resection of which part of the gastrointestinal tract?
Your Answer:
Correct Answer: Ileum
Explanation:Bile acids (also called bile salts) are produced in the liver, secreted into the biliary system, stored in the gallbladder and are released after meals stimulated by cholecystokinin. They are important for the digestion and absorption of fats (lipids) in the small intestine. Usually over 95% of the bile acids are absorbed in the terminal ileum and are taken up by the liver and resecreted.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 13
Incorrect
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Regarding the structure of the 3 pituitary glycoprotein hormones FSH, LH, and TSH, which of the following is true about the α- and β-subunits of each hormone?
Your Answer:
Correct Answer: Maximal physiological activity occurs only on their combination
Explanation:Glycoprotein hormones (GPHs) are the most complex molecules that function as hormones. They each consist of two different subunits, α and β, which are non-covalently associated. The combination of these subunits results in an increase in their activity and β structure.
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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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A 56-year-old male presents to the emergency department with confusion and agitation for the past four hours. He is a known alcoholic who has abstained from drinking for the past three days.On examination, he is sweating, agitated and disorientated. His temperature is 37.7°C, pulse 112 bpm regular and blood pressure is 150/76 mmHg. Blood investigations performed in the emergency department reveal:FBC: NormalU&E: NormalPlasma glucose: 4.6 mmol/l (3.6-6)Which of the following medications would be the most appropriate treatment for this man?
Your Answer:
Correct Answer: Oral lorazepam
Explanation:The most probable diagnosis for this patient is delirium tremens due to alcohol withdrawal, which should be treated as a medical emergency. Delirium tremens is a hyperadrenergic state and is often associated with tachycardia, hyperthermia, hypertension, tachypnoea, tremor, and mydriasis.Treatment:- The most common and validated treatment for alcohol withdrawal is benzodiazepine: first-line treatment includes oral lorazepam. – If the symptoms persist, or the medication is refused, parenteral lorazepam, haloperidol or olanzapine should be given.- Central-acting, alpha-2 agonists such as clonidine and dexmedetomidine should not be used alone for the treatment of alcohol withdrawal.- It is also recommended to avoid using alcohol, antipsychotics, anticonvulsants, beta-adrenergic receptor blockers, and baclofen for the treatment of alcohol withdrawal as there are not enough studies to support the safety of these.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 15
Incorrect
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The residual cleft of the intermediate lobe of the pituitary is lined by follicles resembling which human gland?
Your Answer:
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 16
Incorrect
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HCL is secreted by which cells in the stomach
Your Answer:
Correct Answer: Parietal cells
Explanation:Parietal cells are the epithelial cells that secrete hydrochloric acid (HCl) and intrinsic factor. These cells are located in the gastric glands found in the lining of the fundus and in the body of the stomach.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 17
Incorrect
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Gastrin activates all of the following cells except:
Your Answer:
Correct Answer: Mucus neck cells
Explanation:The G cell is a type of cell in the stomach and duodenum that secretes gastrin. It works in conjunction with gastric chief cells and parietal cells. G cells are found deep within the pyloric glands of the stomach antrum, and occasionally in the pancreas and duodenum. Gastrin-releasing peptide, as well as the presence of amino acids in the stomach, stimulates the release of gastrin from the G cells. Gastrin stimulates enterochromaffin-like cells to secrete histamine. Gastrin also targets parietal cells by increasing the amount of histamine and the direct stimulation by gastrin, causing the parietal cells to increase HCl secretion in the stomach.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 18
Incorrect
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The Cellular Theory of Ageing involves?
Your Answer:
Correct Answer: Loss of telomeres
Explanation:Cellular theories of aging propose that human aging is the result of cellular aging, whereby an increasing proportion of cells reach senescence, a terminal stage at which cells will cease to divide. This will limit the body’s ability to regenerate and to respond to injury or stress. Telomeres are bits of DNA on the ends of chromosomes that protect chromosomes from sticking to each other or tangling, which could cause DNA to abnormally function. As cells replicate, telomeres shorten at the end of chromosomes, and this process correlates to senescence or cellular aging.
Other theories include:
- The Free Radical Theory: Implicates the gradual accumulation of oxidative cellular damage as a fundamental driver of cellular aging. This theory has evolved over time to emphasize the role of free radical induced mitochondrial DNA (mtDNA) mutations and the accumulation of mtDNA deletions. Given the proximity of mtDNA to the electron transport chain, a primary producer of free radicals, it postulates that the mutations would promote mitochondrial dysfunction and concomitantly increase free radical production in a positive feedback loop. It is known that diet, lifestyle, drugs (e.g. tobacco and alcohol) and radiation etc., are all accelerators of free radical production within the body.
- Error theory: based on the idea that errors can occur in the transcription of the synthesis of DNA. These errors are perpetuated and eventually lead to systems that do not function at the optimum level. The organism’s aging and death are attributable to these events (Sonneborn, 1979).
- The Cross-Linking Theory: also referred to as the Glycosylation Theory of Aging. In this theory it is the binding of glucose (simple sugars) to protein, (a process that occurs under the presence of oxygen) that causes various problems. Once this binding has occurred the protein becomes impaired and is unable to perform as efficiently. Living a longer life is going to lead to the increased possibility of oxygen meeting glucose and protein and known cross-linking disorders include senile cataract and the appearance of tough, leathery and yellow skin.
- The Neuroendocrine Theory First proposed by Professor Vladimir Dilman and Ward Dean MD, this theory elaborates on wear and tear by focusing on the neuroendocrine system. This system is a complicated network of biochemicals that govern the release of hormones which are altered by the walnut sized gland called the hypothalamus located in the brain. The hypothalamus controls various chain-reactions to instruct other organs and glands to release their hormones etc. The hypothalamus also responds to the body hormone levels as a guide to the overall hormonal activity. But as we grow older the hypothalamus loses it precision regulatory ability and the receptors which uptake individual hormones become less sensitive to them. Accordingly, as we age the secretion of many hormones declines and their effectiveness (compared unit to unit) is also reduced due to the receptors down-grading
- The Membrane Theory of Aging: According to this theory it is the age-related changes of the cell’s ability to transfer chemicals, heat and electrical processes that impair it. As we grow older the cell membrane becomes less lipid (less watery and more solid). This impedes its efficiency to conduct normal function and in particular there is a toxic accumulation
- The Decline Theory: The mitochondria are the power producing organelles found in every cell of every organ. Their primary job is to create Adenosine Triphosphate (ATP) and they do so in the various energy cycles that involve nutrients such as Acetyl-L-Carnitine, CoQ10 (Idebenone), NADH and some B vitamins etc. Enhancement and protection of the mitochondria is an essential part of preventing and slowing aging. Enhancement can be achieved with the above mention nutrients, as well as ATP supplements themselves.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 19
Incorrect
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Which of the following increase insulin secretion?
Your Answer:
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 20
Incorrect
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In Hirschsprung disease which one is incorrect
Your Answer:
Correct 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 21
Incorrect
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The ability of the SA node cells to allow ionic flow through channels activated in a hyperpolarized state is known as:
Your Answer:
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 22
Incorrect
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Which of the following conditions is associated with eosinophilia?
Your Answer:
Correct Answer: Ascaris
Explanation:Eosinophilia can be idiopathic (primary) or, more commonly, secondary to another disease. In the Western World, allergic or atopic diseases are the most common causes, especially those of the respiratory or integumentary systems. In the developing world, parasites are the most common cause e.g. Ascaris
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This question is part of the following fields:
- Haematology
- Medicine
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Question 23
Incorrect
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Which statement describes endogenous transmission the best?
Your Answer:
Correct Answer: Commensal flora that gain access to an inappropriate area
Explanation:All answers A, B, C, and D are examples of exogenous infections. Endogenous infection is an infection by organisms that normally reside in the body but have previously been dormant.
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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Question 24
Incorrect
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Normally the portal venous pressure is about:
Your Answer:
Correct Answer: 5mmhg
Explanation:Under normal physiological conditions, the pressure in the portal vein, which carries blood from the gastrointestinal tract and spleen to the liver, typically ranges around 5-10 mmHg. Pressures significantly higher than this range can indicate portal hypertension, which can be associated with liver diseases such as cirrhosis.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 25
Incorrect
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Which enzyme hydrolyses triglycerides in lipoproteins into free fatty acids for storage in fat cells?
Your Answer:
Correct Answer: Lipoprotein lipase
Explanation:Lipoprotein lipase is a water-soluble enzyme that hydrolyses triglycerides in lipoproteins, such as those found in chylomicrons and very low-density lipoproteins (VLDL), into two free fatty acids and one monoacylglycerol molecule.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 26
Incorrect
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Periodic fevers occur in humans with mutations in the gene for pyrin. Pyrin is a protein found in which one of the following cells?
Your Answer:
Correct Answer: Neutrophils
Explanation:Pyrin, also known as marenostrin or TRIM20, is a protein encoded by the Mediterranean fever (MEFV) gene, causing the autoinflammatory disease familial Mediterranean fever (FMF). Pyrin produces an increased sensitivity to intracellular signals. It is produced mainly in neutrophils, which display an increased ratio of cells entering apoptosis when exposed to pyrin.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 27
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:
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 28
Incorrect
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Question 29
Incorrect
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A 25-year-old male presents to the emergency department with fever, sweating, hyperventilation and breathing difficulty. He also complains of a continuous ringing sensation in both his ears for the past couple of days. He admits to consuming a lot of over the counter painkillers for the past few days. Which of the following drugs is the most likely cause of these symptoms?
Your Answer:
Correct Answer: Aspirin
Explanation:The presence of tinnitus, fever and hyperventilation are clues for aspirin (salicylate) toxicity. Clinical Presentation of salicylate toxicity can include:• Pulmonary manifestations include: Hyperventilation, hyperpnea, severe dyspnoea due to noncardiogenic pulmonary oedema, fever and dyspnoea due to aspiration pneumonitis• Auditory symptoms caused by the ototoxicity of salicylate poisoning include: Hard of hearing and deafness, and tinnitus (commonly encountered when serum salicylate concentrations exceed 30 mg/dL).• Cardiovascular manifestations include: Tachycardia, hypotension, dysrhythmias – E.g., ventricular tachycardia, ventricular fibrillation, multiple premature ventricular contractions, asystole – with severe intoxication, Electrocardiogram (ECG) abnormalities – E.g., U waves, flattened T waves, QT prolongation may reflect hypokalaemia.• Neurologic manifestations include: CNS depression, with manifestations ranging from somnolence and lethargy to seizures and coma, tremors, blurring of vision, seizures, cerebral oedema – With severe intoxication, encephalopathy• GI manifestations include: Nausea and vomiting, which are very common with acute toxicity, epigastric pain, GI haemorrhage – More common with chronic intoxication, intestinal perforation, pancreatitis, hepatitis – Generally in chronic toxicity; rare in acute toxicity, Oesophageal strictures – Reported as a very rare delayed complication• Genitourinary manifestations include: Acute kidney injury (NSAID induced Nephropathy) is an uncommon complication of salicylate toxicity, renal failure may be secondary to multisystem organ failure.• Hematologic effects may include prolongation of the prothrombin and bleeding times and decreased platelet adhesiveness. Disseminated intravascular coagulation (DIC) may be noted with multisystem organ failure in association with chronic salicylate toxicity.• Electrolyte imbalances like: Dehydration, hypocalcaemia, acidaemia, Syndrome of inappropriate antidiuretic hormone secretion (SIADH), hypokalaemiaManagement of these patients should be done in the following manner:• Secure Airway, Breathing, and Circulation• Supportive therapy• GI decontamination• Urinary excretion and alkalization• Haemodialysis
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 30
Incorrect
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A 68 year old man presents with acute symptoms of gout on his first metatarsophalangeal joint. Which option best explains the underlying mechanism of gout?
Your Answer:
Correct Answer: Decreased renal excretion of uric acid
Explanation:Primary gout is related more often to underexcretion of uric acid or overproduction.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 31
Incorrect
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With regards to the deiodinases, where would you find D1?
Your Answer:
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 32
Incorrect
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In liver failure there is likely to be?
Your Answer:
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 33
Incorrect
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What is the mechanism of action of sumatriptan?
Your Answer:
Correct Answer: 5-HT1 agonist
Explanation:Triptans are specific 5-HT1 agonists used in the acute treatment of migraine. They are generally used as first-line therapy in combination with an NSAID or paracetamol.
Sumatriptan acts as an agonist on 5-HT1B/1D receptors by inducing vasoconstriction in the basilar artery and blood vessels within the dura mater. The drug reduces peripheral nociception either by selective cranial vasoconstriction or by affecting trigeminovascular nerves.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 34
Incorrect
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Which of the following statements is false regarding the bioavailability of a drug?
Your Answer:
Correct Answer: The bioavailability of a drug given orally is often affected by the degree of renal elimination
Explanation:Renal elimination of a drug has no role in altering the bioavailability of a drug.The bioavailability of a drug is the proportion of the drug which reaches systemic circulation. Mathematically, bioavailability is the AUCoral/AUCiv x 100%, where AUC = area under the concentration-time curve following a single (oral or iv) dose. Other options are true:By definition, the bioavailability of a drug given intravenously is 100%.Drugs given orally that undergo high pre-systemic (first-pass) metabolism in the liver or gut wall have a low bioavailability e.g. lidocaine. Bioavailability is also affected by the degree of absorption from the gut and this can change depending on gut motility and administration of other drugs.
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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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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 36
Incorrect
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In DNA cloning and sequencing, the bases in nucleotides chains are bound together by:
Your Answer:
Correct Answer: Hydrogen bonding.
Explanation:Nucleotides will always bind together via hydrogen bonds. There are two hydrogen bonds present between thymine and adenine and three hydrogen bonds present between guanine and cytosine.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 37
Incorrect
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Angina pectoris develops when blood through the coronary artery becomes:
Your Answer:
Correct Answer: Restricted, limiting blood blow
Explanation:Angina pectoris develops when stenosis ( >70%) of the artery occurs as a result of formation of an atherosclerotic plaque. This leads to a decrease in the O2 carried to the thickened heart muscle by the blood, leading to the characteristic chest pain associated with angina pectoris.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 38
Incorrect
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The lamina propria contains all of the following except:
Your Answer:
Correct Answer: Neutrophils
Explanation:The connective tissue of the lamina propria is very loose, allowing it to be very cell rich. The cell population of the lamina propria is variable and can include, for example, fibroblasts, lymphocytes, plasma cells, macrophages, eosinophilic leukocytes, and mast cells. It provides support and nutrition to the epithelium, as well as the means to bind to the underlying tissue.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 39
Incorrect
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Select the correct statement regarding portal hypertension.
Your Answer:
Correct Answer: The total vascular resistance of the hepatic sinusoids is increased.
Explanation:Portal hypertension is increased blood pressure within the portal venous system. This happens mainly due to liver damage which increases the vascular resistance of hepatic sinusoids by interfering with the normal blood flow. Portal blood pressure increases and flow through the liver decreases. Normal portal venous pressure is between 5-10 mmHg and in portal hypertension it’s usually more than 10 mmHg. This high pressure can cause accumulation of fluid in the peritoneal cavity known as ascites. To overcome the pressure, the portal vein starts to drain blood to systemic circulation via porto-systemic shunts. The connection between the portal vein and inferior vena cava is known as the porto caval shunt. Due to damaged hepatocytes, detoxification of substances absorbed in the intestine is impaired and the former shunt mixes non-detoxified blood with the systemic circulation. These toxic substances may affect neurons causing hepatic encephalopathy which is a major complication of portal hypertension.
-
This question is part of the following fields:
- Hepatobiliary
- Medicine
-
-
Question 40
Incorrect
-
Which of the following drugs requires plasma level monitoring?
Your Answer:
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.
-
This question is part of the following fields:
- Medicine
- Pharmacology
-
-
Question 41
Incorrect
-
The initial rapid depolarization in the action potential of cardiac muscle cells is due to:
Your Answer:
Correct 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.
-
This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 42
Incorrect
-
Question 43
Incorrect
-
A 42 year old obese man complains of a painful swollen ankle. The pain has worsened over the past 2 weeks. He is a diabetic and gives a history of recent alcohol consumption. Joint aspirate shows rhomboid crystals with numerous neutrophils. Radiological examination shows evidence of chondrocalcinosis. Which of the following is the most likely diagnosis?
Your Answer:
Correct Answer: Pseudogout
Explanation:Pseudogout is a paroxysmal joint inflammation due to calcium pyrophosphate crystal deposition (calcium pyrophosphate dihydrate). Aetiology includes mostly idiopathic (primary form) and secondary form occurring as a result of joint trauma, familial chondrocalcinosis, hyperparathyroidism, hemochromatosis, gout, hypophosphatemia. Clinical presentation: Often asymptomatic. Acute (pseudogout attack): monoarthritis (rarely oligoarthritis), mostly affecting the knees and other large joints (e.g., hips, wrists, and ankles). It may become chronic (can affect multiple joints). Osteoarthritis with CPPD (most common form of symptomatic CPPD): progressive joint degeneration with episodes of acute inflammatory arthritis typical of pseudogout attacks. Arthrocentesis should be performed, especially in acute cases. Polarized light microscopy: detection of rhomboid-shaped, positively birefringent CPPD crystals. Synovial fluid findings: 10,000-50,000 WBCs/μL with > 90% neutrophils. X-ray findings: cartilage calcification of the affected joint (chondrocalcinosis). Fibrocartilage (meniscus, annulus fibrosus of intervertebral disc) and hyaline cartilage (joint cartilage) may be affected.
-
This question is part of the following fields:
- Connective Tissue
- Medicine
-
-
Question 44
Incorrect
-
Question 45
Incorrect
-
Question 46
Incorrect
-
Where is Müllerian inhibiting substance (MIS) secreted?
Your Answer:
Correct Answer: Sertoli cells
Explanation:Müllerian inhibiting substance, also known as Anti-Müllerian hormone (AMH) or Müllerian-inhibiting hormone (MIH) is a glycoprotein hormone which prevents the development of the Müllerian ducts into the uterus. Its production by Sertoli cells continues during childhood in males and decreases after puberty.
-
This question is part of the following fields:
- Endocrinology
- Medicine
-
-
Question 47
Incorrect
-
Excitation-contraction coupling in cardiac muscle involves all of the following except:
Your Answer:
Correct Answer: Binding of Ca2+ to calmodulin
Explanation:In the excitation contraction coupling model, an action potential is transmitted to the fibrils of a fiber through the T tubule system. It triggers the release of Ca 2+ from the terminal cisterns. Depolarization of the T tubules activates the sarcoplasmic reticulum through the dihydropyridine receptors. These are voltage gates calcium channels. Calcium binds to calmodulin during contraction of the smooth muscle and not the cardiac muscles.
-
This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 48
Incorrect
-
What is the mechanism of action of carbimazole?
Your Answer:
Correct Answer: Inhibition of the iodination of tyrosine
Explanation:Carbimazole is used to treat hyperthyroidism. Carbimazole is a pro-drug as after absorption it is converted to the active form, methimazole. Methimazole prevents thyroid peroxidase enzyme from coupling and iodinating the tyrosine residues on thyroglobulin, hence reducing the production of the thyroid hormones T3 and T4 (thyroxine).
-
This question is part of the following fields:
- Medicine
- Pharmacology
-
-
Question 49
Incorrect
-
What is the primary problem of achalasia
Your Answer:
Correct 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.
-
This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 50
Incorrect
-
The first enzyme carbohydrates encounter in the digestive tract is?
Your Answer:
Correct Answer: Amylase
Explanation:Carbohydrate digesting enzymes are known as amylase. Salivary amylase or ptyalin is the first enzyme to begin carbohydrate digestion in he oral cavity. Amylose is a component of carbohydrates and is not an enzyme. Isomaltase, maltase and sucrase are enzymes found in the small intestines that digest disaccharides like maltose and sucrose to monosaccharides.
-
This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 51
Incorrect
-
Direct conduction from the atrium to the ventricles is prevented by:
Your Answer:
Correct Answer: Annulus fibrosus
Explanation:The annulus fibrosus disconnects the syncytium complex. The atria are rapidly activated however the activation peters out when the insulating layer-the annulus fibrosus-is reached.
-
This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 52
Incorrect
-
A 60 year old male presents with thickened patches of skin over his knuckles and extensor surfaces that are consistent with Gottron's papules. Results reveal an elevated creatine kinase. Diagnosis of dermatomyositis is suspected. Which of the following autoantibody is most specific for this condition?
Your Answer:
Correct Answer: Anti-Mi-2 antibodies
Explanation:Anti–Mi-2 antibodies are highly specific for dermatomyositis, but sensitivity is low; only 25% of patients with dermatomyositis demonstrate these antibodies. A positive antinuclear antibody (ANA) finding is common in patients with dermatomyositis, but is not necessary for diagnosis. Anti-Jo-1 antibodies are mostly associated with polymyositis. Anti Scl-70 antibodies and anti centromere antibodies are most commonly found in systemic scleroderma.
-
This question is part of the following fields:
- Connective Tissue
- Medicine
-
-
Question 53
Incorrect
-
The central veins in the liver:
Your Answer:
Correct Answer: Coalesce to form the hepatic vein
Explanation:The central veins coalesce to form the hepatic vein which in turn drains into the inferior vena cava. The portal vein mainly carries blood from different parts of the GIT and is not drained to the inferior vena cava.
-
This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 54
Incorrect
-
The spinal cord receive its blood supply from the following arteries except:
Your Answer:
Correct Answer: Lateral spinal artery
Explanation:The spinal cord (SC) is supplied by the single anterior spinal artery which supplies the anterior two thirds of the SC and paired posterior spinal arteries supplying the posterior one third. Anastomoses between the spinal arteries supply the lateral column. These arteries originate near the cervico-occipital junction and therefore have a smaller calibre and often discontinue. Thus, they require reinforcement by segmental/radicular arteries which are branches of the ascending cervical artery, deep cervical artery, intercostal arteries, lumbar arteries and lateral sacral arteries
-
This question is part of the following fields:
- Medicine
- Neurology
-
-
Question 55
Incorrect
-
“Ploidy” is a term used to refer to the number of chromosomes in cells. Cancer cells are commonly:
Your Answer:
Correct Answer: Aneuploidy
Explanation:Cancer cells most commonly undergo disordered cell growth and cell division. This results in an additional number of chromosomes called aneuploidy. This is a characteristic of cancer cells along with variation in differentiation of the cells.
-
This question is part of the following fields:
- Genetics
- Medicine
-
-
Question 56
Incorrect
-
Vasodilatation in skeletal muscle can be caused by:
Your Answer:
Correct Answer: Sympathetic cholinergic nerves
Explanation:In skeletal muscles some fibers that cause vasodilation run with the nerves of the sympathetic system but are cholinergic in nature. These nerves are not active during rest but become active during exercise and stress.
-
This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 57
Incorrect
-
Male to male transmission is a key factor of which type of inheritance?
Your Answer:
Correct Answer: Autosomal dominant
Explanation:Autosomal dominant type of inheritance can include both sexes in the same ratio. There is no skipping a generation and father to son transmission is common. The passing of the trait is sex independent.
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This question is part of the following fields:
- Genetics
- Medicine
-
-
Question 58
Incorrect
-
Question 59
Incorrect
-
A 40-year-old patient under treatment for gout gave a history of progressive weakness of his limbs over 2 months. He noticed that it was particularly difficult for him to get up from the toilet seat and to get out of his car. He also felt some tingling and numbness of his toes at night, which was distressing. He was taking several medications which included Ibuprofen, perindopril, colchicine, vitamin supplements, and indapamide.On examination his pulse was 85/min, blood pressure was 140/90 mmHg and fundi revealed arteriovenous nipping. He had proximal lower limb weakness of 4/5 and absent ankle reflexes. Plantar reflexes were upgoing on both sides. His serum creatinine phosphokinase level was normal.What is the most likely diagnosis?
Your Answer:
Correct Answer: Colchicine toxicity
Explanation:The given clinical scenario is suggestive of myo-neuropathy and is most likely to be caused by colchicine toxicity. It gives rise to subacute proximal muscle weakness and on occasions can lead to an acute necrotizing myopathy. Creatine phosphokinase may be normal or may be elevated.Weakness resolves when the drug is discontinued but the neuropathic features remain.Death is usually a result of respiratory depression and cardiovascular collapse.Treatment is symptomatic and supportive, and the treatment for colchicine poisoning includes lavage and measures to prevent shock.
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This question is part of the following fields:
- Medicine
- Pharmacology
-
-
Question 60
Incorrect
-
Which of the following features do mast cells and basophils have in common:
Your Answer:
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
-
-
Question 61
Incorrect
-
With regards to the Na+/K+ ATPase, which one of the following is correct?
Your Answer:
Correct Answer: 3 Na+ released into the extracellular fluid
Explanation:Na+/K+ pump or sodium–potassium pump is an enzyme found in the plasma membrane. This pumping is active (i.e. it uses energy from ATP) and is important for cell physiology. Its simple function is to pump 3 sodium ions out for every 2 potassium ions taken in and since they both have equal ionic charges, this creates a electrochemical gradient between a cell and its exterior.
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This question is part of the following fields:
- Cell Biology
- Medicine
-
-
Question 62
Incorrect
-
In the body what are fatty acids broken down to?
Your Answer:
Correct Answer: Acetyl Co A
Explanation:Fatty acids are broken down into acetyl Co A. The acetyl-CoA produced by beta oxidation enters the citric acid cycle in the mitochondrion by combining with oxaloacetate to form citrate.
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This question is part of the following fields:
- Cell Biology
- Medicine
-
-
Question 63
Incorrect
-
Which of the following conditions has no effect on cardiac output?
Your Answer:
Correct Answer: Sleep
Explanation:Sleep has no effect on the cardiac output. Anxiety, excitement and pregnancy will increase the cardiac output. Standing from a lying position will decrease the cardiac output transiently.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 64
Incorrect
-
Select the correct statement regarding the macro anatomy of the thyroid gland.
Your Answer:
Correct Answer: It surrounds the trachea at the front of the neck.
Explanation:The thyroid is located around the trachea, in the anterior portion of the neck. It is formed by two lobes which are connected by an isthmus. The presence of a pyramidal lobe, or third lobe, is considered to be a normal anatomical variant. It originates from the primitive pharynx and the neural crest and has a rich vascular supply.
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This question is part of the following fields:
- Endocrinology
- Medicine
-
-
Question 65
Incorrect
-
Intermediate filaments achieve cell to cell contact via:
Your Answer:
Correct Answer: Desmosomes
Explanation:At the plasma membrane, some keratins interact with desmosomes (cell-cell adhesion) and hemidesmosomes (cell-matrix adhesion) via adapter proteins.
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This question is part of the following fields:
- Cell Biology
- Medicine
-
-
Question 66
Incorrect
-
The amount of a substance taken up by an organ (or whole body) per unit time is = (the arterial level - the venous level) * the blood flow. This statement describes?
Your Answer:
Correct Answer: The Fick principle
Explanation:The essence of the Fick principle is that blood flow to an organ can be calculated using a marker substance if the following information is known:- Amount of marker substance taken up by the organ per unit time- Concentration of marker substance in arterial blood supplying the organ- Concentration of marker substance in venous blood leaving the organ
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 67
Incorrect
-
A 28 year old male arrives at the clinic complaining of fever, arthralgia and urethritis. On examination, the ankle is swollen and there is a pustular rash on the dorsal foot. What is the most likely diagnosis?
Your Answer:
Correct Answer: Disseminated gonorrhoea
Explanation:DGI presents as two syndromes: 1) a bacteremic form that includes a triad of tenosynovitis, dermatitis, and polyarthralgias without purulent arthritis and 2) a septic arthritis form characterized as a purulent arthritis without associated skin lesions. Many patients will have overlapping features of both syndromes. Time from infection to clinical manifestations may range from 1 day to 3 months. There is no travel history and the rash of Lyme disease is not purulent. Reactive arthritis presents with conjunctivitis, urethritis and arthritis usually with a red hot tender and swollen joint.
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This question is part of the following fields:
- Connective Tissue
- Medicine
-
-
Question 68
Incorrect
-
Which of the following hormones cause negative feedback on the CRH/ACTH axis?
Your Answer:
Correct Answer: Cortisol
Explanation:The hypothalamic–pituitary–adrenal axis, also known as HPA axis is a set of interactions that regulate the secretion of several hormones through negative feedback. Cortisol, for example, is produced by the adrenal cortex, binds to its receptors in the hypothalamus and adenohypophysis and inhibits secretion of corticotropin releasing hormone (CRH) and adrenocorticotropic hormone (ACTH). The drop in CRH secretion leads to a decrease in ACTH secretion, which in turn causes less cortisol to be secreted.
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This question is part of the following fields:
- Endocrinology
- Medicine
-
-
Question 69
Incorrect
-
There is normally an inverse relationship between the hepatic artery and portal venous blood flow. This is maintained by:
Your Answer:
Correct Answer: All of the options are correct
Explanation:There is an inverse relationship between the blood flow of the hepatic artery and portal vein. It is maintained by several factors such as chemicals like adenosine, neurohumoral substances, the morphology of the hepatic portal system (especially the ability of hepatic sinusoids to collapse) and myogenic control which causes vasoconstriction or vasodilation.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 70
Incorrect
-
In a 60kg adult male with normal mean arterial pressure and oxygen consumption, what proportion of the cardiac output at rest goes to the brain?
Your Answer:
Correct Answer: 10-15%
Explanation:The rate of cerebral blood flow in the adult is typically 750 millilitres per minute, which is 10-15% of the cardiac output. On average around 13.9% of cardiac output is distributed to the brain.
-
This question is part of the following fields:
- Medicine
- Neurology
-
-
Question 71
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 72
Incorrect
-
Regarding bronchial innervation which of the following is correct:
Your Answer:
Correct Answer: Alpha 1 receptors increase bronchial constriction
Explanation:Stimulation of β2 receptors results in smooth muscle relaxation and bronchodilation. α1 receptors cause smooth muscle contraction in the bronchioles although minor to the β2 effects.
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This question is part of the following fields:
- Medicine
- Respiratory
-
-
Question 73
Incorrect
-
Which of the following is true with regard to the acini?
Your Answer:
Correct Answer: The central zone (Zone III) is the least oxygenated
Explanation:The acini are divided into zone I (periportal), zone II (transition zone), and zone III (pericentral). Cells located close to the portal triad or peripheral zone which consist of an arteriole from the hepatic artery are the most oxygenated cells. Cells in the central zone (III) are least oxygenated and mainly receive blood supply from the central vein which is a branch of hepatic vein.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 74
Incorrect
-
The inverse stretch reflex causing muscle relaxation when excessive force is applied to a muscle is mediated by which sensory organ?
Your Answer:
Correct Answer: Golgi tendon organ
Explanation:Both the muscle spindle and Golgi tendon body are proprioceptors. The Golgi tendon reflex is a normal component of the reflex arc of the peripheral nervous system. In a Golgi tendon reflex, skeletal muscle contraction causes the antagonist muscle to simultaneously lengthen and relax. This reflex is also called the inverse myotatic reflex, because it is the inverse of the stretch reflex.
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This question is part of the following fields:
- Medicine
- Neurology
-
-
Question 75
Incorrect
-
The haustral pattern seen in the normal colon is produced by
Your Answer:
Correct Answer: Taenia coli
Explanation:The haustra (singular haustrum) of the colon are the small pouches caused by sacculation (sac formation), which give the colon its segmented appearance. The teniae coli run the length of the large intestine. Because the taeniae coli are shorter than the intestine, the colon becomes sacculated between the taeniae coli, forming the haustra.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 76
Incorrect
-
Regarding Polymerase Chain Reaction, all are true except:
Your Answer:
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.
-
This question is part of the following fields:
- Genetics
- Medicine
-
-
Question 77
Incorrect
-
Which enzyme is responsible for the conversion of testosterone to dihydrotestosterone?
Your Answer:
Correct 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.
-
This question is part of the following fields:
- Endocrinology
- Medicine
-
-
Question 78
Incorrect
-
Arterioles stemming from the coronary artery can also empty into the heart directly via the:
Your Answer:
Correct Answer: Arteriosinusoidal vessels
Explanation:Most of the venous blood returns to the heart via the coronary sinus and the anterior cardiac veins. Apart from these there are other vessels that drain directly into the heart chambers. They include arteriosinusoidal vessels, which connect the arterioles to the heart chambers. The thebesian veins drain the capillaries into the chambers and the arterioluminal vessels drain small arteries directly into the chambers.
-
This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 79
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 80
Incorrect
-
In the functional unit of the liver (acinus), the oxygenation…
Your Answer:
Correct Answer: Reduces towards the centre
Explanation:Cells located close to the portal triad or peripheral zone which consist of arterioles from the hepatic artery are the most oxygenated cells. Cells in the central zone are least oxygenated and mainly receive blood supply from the central vein which is a branch of the hepatic vein.
-
This question is part of the following fields:
- Hepatobiliary
- Medicine
-
-
Question 81
Incorrect
-
Nucleic acids are split into nucleotides in the:
Your Answer:
Correct 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.
-
This question is part of the following fields:
- Medicine
- Metabolism
-
-
Question 82
Incorrect
-
β-blockers are used in the treatment of angina because they have which one of the following properties?
Your Answer:
Correct Answer: Decrease the heart rate and myocardial contractility
Explanation:The cardiovascular effects of β-adrenoceptor block result from reduction of the sympathetic drive which includes reduced heart rate (automaticity) and reduced myocardial contractility (rate of rise of pressure in the ventricle). This will lead to reduced cardiac output and an overall fall in oxygen consumption.
-
This question is part of the following fields:
- Medicine
- Pharmacology
-
-
Question 83
Incorrect
-
In which area is depolarization initiated?
Your Answer:
Correct Answer: SA node
Explanation:SA node is the pacemaker of the heart. It determines the rate of contractions. It is the place where depolarization is initiated. It exhibits phase 4 depolarization or automaticity. Electrical impulses then spread to the AV node, purkinje fibers, bundle of his and the ventricular muscles.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 84
Incorrect
-
An 18 year old boy, thin with a tall stature, and a high arched palate arrives at the hospital with a spontaneous pneumothorax. He is accompanied by his brother who has a similar appearance. You suspect Marfan's Syndrome. The gene encoding which of the following proteins is defective in this condition?
Your Answer:
Correct Answer: Fibrillin-1
Explanation:A variety of proteins compose the structure of microfibrils, the most prominent of which are the two fibrillins. Fibrillin-1 a scaffolding protein is encoded by FBN1 on human chromosome 15q21 and fibrillin-2 is encoded by FBN2 on 5q23. Mutations in FBN1 produce Marfan syndrome, a pleiotropic autosomal dominant connective tissue disorder with prominent manifestations in the skeleton, eye and cardiovascular system. A number of conditions related to Marfan syndrome are also due to FBN1 mutations.
-
This question is part of the following fields:
- Connective Tissue
- Medicine
-
-
Question 85
Incorrect
-
During quiet breathing the diaphragm’s role accounts for what percent of respiration?
Your Answer:
Correct Answer: 75%
Explanation:The contraction of the diaphragm accounts for approximately 75% of the air movement during normal breathing.
-
This question is part of the following fields:
- Medicine
- Respiratory
-
-
Question 86
Incorrect
-
What is the most abundant cell type in the central nervous system called?
Your Answer:
Correct Answer: Astrocyte
Explanation:Astrocytes are the supporting cells of the central nervous system. There are two types; the fibrous type is found in the white matter and the protoplasmic type in the grey matter. They are the most abundant cell type in the CNS.
-
This question is part of the following fields:
- Medicine
- Neurology
-
-
Question 87
Incorrect
-
Question 88
Incorrect
-
Phosphorylation of glucose once it enters the cell is catalysed by which enzyme?
Your Answer:
Correct Answer: Hexokinase
Explanation:Glucose 6-phosphate is produced by phosphorylation of glucose on the sixth carbon. This is catalysed by the enzyme hexokinase in most cells. One molecule of ATP is consumed in this reaction.
-
This question is part of the following fields:
- Medicine
- Metabolism
-
-
Question 89
Incorrect
-
Which of the following biochemical profiles is seen in a normal 65 year old female? (in comparison to a normal 24 yr. old female)
Your Answer:
Correct Answer: Increased FSH, LH; decreased oestrogen, progesterone
Explanation:During menopause, a woman’s number of ovarian follicles becomes depleted; as a result, oestrogen and progesterone levels drop, and LH and FSH levels increase. One of the criteria to diagnose menopause is the absence of menstrual period for a year, along with a serum FSH level increased to 30 mIU/ml or higher. LH also rises with the onset of menopause.
-
This question is part of the following fields:
- Endocrinology
- Medicine
-
-
Question 90
Incorrect
-
Phosphate absorption in the proximal tubules is via which transporting molecule?
Your Answer:
Correct Answer: Na/Pi co transporter
Explanation:Sodium/phosphate cotransporters are located in the renal proximal tubular brush border, and are the key elements in proximal tubular phosphate reabsorption and phosphate homeostasis.
-
This question is part of the following fields:
- Endocrinology
- Medicine
-
-
Question 91
Incorrect
-
A 33 year old female presents with dyspnoea, myalgia, arthralgia and a skin rash. The presence of which of the following antibodies would be the most specific for SLE?
Your Answer:
Correct Answer: Anti-Sm
Explanation:Anti-Sm antibodies are essential for diagnosis of SLE, especially in anti-dsDNA-negative patients. ANA are also found in 95% of the patients with SLE but they may also occur with other conditions like Juvenile inflammatory arthritis, chronic activity hepatitis, and Sjogren’s syndrome. Anti-Ro, although also found with SLE are more characteristic of Sjogren Syndrome. RF is usually associated with rheumatoid arthritis and cANCA with Wegener’s granulomatosis, Churg Strauss, and microscopic polyangiitis.
-
This question is part of the following fields:
- Connective Tissue
- Medicine
-
-
Question 92
Incorrect
-
Acetylcholine from enteric nerve endings stimulates this pair:
Your Answer:
Correct Answer: Parietal cells and chief cells
Explanation:In the body of the stomach, the vagal postganglionic muscarinic nerves release acetylcholine(ACh) which stimulates parietal cell H+ secretion. Gastric chief cells are primarily activated by ACh. However the decrease in pH caused by activation of parietal cells further activates gastric chief cells.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 93
Incorrect
-
Regarding CSF:
Your Answer:
Correct Answer: Disruption of arachnoid villi function results in a communicating hydrocephalus
Explanation:In normal adults CSF volume is around 125ml to 150ml. Turnover of the entire volume of cerebrospinal fluid is about 3 to 4 times a day. Composition of CSF is similar to that of plasma except that CSF is nearly protein-free compared with plasma and has different electrolyte levels. Blockage of the foramina causes an obstructive or non-communicating hydrocephalus. Communicating hydrocephalus or non-obstructive hydrocephalus is caused by impaired CSF reabsorption in the absence of any CSF flow obstruction.
-
This question is part of the following fields:
- Medicine
- Neurology
-
-
Question 94
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 95
Incorrect
-
Afferent A δ fibers from nociceptors terminate primarily on neurons in which lamina:
Your Answer:
Correct Answer: I and V
Explanation:Nociceptors are receptors of pain sensation. There are 2 primary afferent/sensory pain fibers which transmit impulses from the receptor to the CNS, specifically to the dorsal horn of the spinal cord. The two fibers are A δ and C fibers. The dorsal horn of the spinal cord is the relay centre for sensory information converging from the periphery. Grey matter of the dorsal horn is subdivided in to laminae based on cytoarchitecture. C fibers terminate in lamina II the substantia gelatinosa. A δ fibers terminate primarily in lamina I but some project more deeply to terminate in lamina V.
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This question is part of the following fields:
- Medicine
- Neurology
-
-
Question 96
Incorrect
-
Which one of these features is typical of dermatomyositis?
Your Answer:
Correct Answer: Gottron's papules over knuckles of fingers
Explanation:The main symptom of dermatomyositis include skin rash and symmetric proximal muscle weakness (in over 90% of patients) which may be accompanied by pain and tenderness. It occurs more commonly in females. Skin findings include:Gottron’s sign – an erythematous, scaly eruption occurring in symmetric fashion over the MCP and interphalangeal jointsHeliotrope or lilac rash – a violaceous eruption on the upper eyelids and in rare cases on the lower eyelids as well, often with itching and swellingShawl (or V-) sign is a diffuse, flat, erythematous lesion over the back and shoulders or in a V over the posterior neck and back or neck and upper chest, which worsens with UV light. Erythroderma is a flat, erythematous lesion similar to the shawl sign but located in other areas, such as the malar region and the forehead. Periungual telangiectasias and erythema occur.
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This question is part of the following fields:
- Dermatology
- Medicine
-
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Question 97
Incorrect
-
A 68 year old male, previously diagnosed with osteoarthritis presents to your clinic with acute on chronic pain in his big toe. Past history is significant for hypertension for which he takes Bendroflumethiazide 5mg daily. Examination reveals an erythematous, red hot metatarsophalangeal joint that has a knobbly appearance. X-ray shows punched out bony cysts. Which of the following would be the most appropriate long term management for this patient?
Your Answer:
Correct Answer: Stop Bendroflumethiazide and substitute a calcium antagonist
Explanation:The most likely diagnosis is chronic tophaceous gout, which is classically associated with chronic renal impairment or long term diuretic therapy. There is tophus formation due to urate crystal deposition in and around the joint. These tophi can also form in the bones and soft tissues. Renal manifestations with uric acid include nephrolithiasis and uric acid nephropathy. Whenever there is an acute on chronic attack of gout, the inciting cause must be established and in case of diuretic use, they should be immediately replaced with another medication. Allopurinol is never started during an acute episode. it is first allowed to settle before administration of allopurinol. Although dietary restriction must be observed in people with a propensity of gout, this scenario clearly presents diuretics as the cause.
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This question is part of the following fields:
- Connective Tissue
- Medicine
-
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Question 98
Incorrect
-
When looking at the JVP what does the c wave signify:
Your Answer:
Correct Answer: Isovolumetric ventricular contraction
Explanation:The C wave signifies a rise in the atrial pressure during isovolumetric contraction due to the tricuspid valve bulging into the atria.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 99
Incorrect
-
The ENaC Transporter occurs in which part of the renal tubule?
Your Answer:
Correct Answer: Collecting duct
Explanation:The epithelial sodium channel (ENaC) is a membrane-bound ion channel that is selectively permeable to Na+ ions. It is involved primarily in the reabsorption of sodium ions at the collecting ducts of the kidney’s nephrons.
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This question is part of the following fields:
- Medicine
- Renal
-
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Question 100
Incorrect
-
Synthesis of haem for haemoglobin occurs in the?
Your Answer:
Correct Answer: Mitochondria of the red blood cells
Explanation:Haemoglobin (Hb) is synthesized in a complex series of steps. The haem part is synthesized in a series of steps in the mitochondria and the cytosol of immature red blood cells, while the globin protein parts are synthesized by ribosomes in the cytosol.
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This question is part of the following fields:
- Haematology
- Medicine
-
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Question 101
Incorrect
-
Xanthines such as caffeine and theophylline are positively inotropic due to:
Your Answer:
Correct Answer: Inhibition of cAMP breakdown
Explanation:Xanthines exert their positive inotropic effect by inhibiting the breakdown of the cAMP resulting in stronger and sustained contractions.
-
This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 102
Incorrect
-
The parasympathetic innervation of the parotid salivary gland arrives from the salivary nuclei:
Your Answer:
Correct Answer: CN IX
Explanation:Parasympathetic presynaptic nerve fibers from the glossopharyngeal nerve (CN IX) synapse in the otic ganglion and the postsynaptic parasympathetic nerve fibers pass to the parotid gland via the auriculotemporal nerve.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
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Question 103
Incorrect
-
Which of the following isoforms of Nitric oxide synthase (NOS) is found in endothelial cells?
Your Answer:
Correct Answer: Nos 3
Explanation:There are only 3 isoforms:NOS 1: found in nervous systemNOS 2: in macrophages and other immune cellsNOS 3: In endothelial cells
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 104
Incorrect
-
The enzyme responsible for telomeres maintaining their length after cell division is called:
Your Answer:
Correct Answer: Telomerase
Explanation:Telomerase is the enzyme responsible for maintenance of the length of telomeres by addition of guanine-rich repetitive sequences. Telomerase activity is exhibited in gametes and stem and tumor cells.
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This question is part of the following fields:
- Genetics
- Medicine
-
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Question 105
Incorrect
-
A 22-year-old female is brought to the emergency department by her friends following the consumption of an unknown drug whilst clubbing. Which of the following features point towards the use of ecstasy?
Your Answer:
Correct Answer: Temperature of 39.5ºC
Explanation:Hyperthermia (Temperature 39.5 C) points towards the use of ecstasy.MDMA (3,4 – methylenedioxymethamphetamine), or more commonly known as Molly or Ecstasy, is a synthetic psychoactive substance.Patients who consumed MDMA may present in a tachycardic, hypertensive, hyperthermic, and agitated state. Adverse effects, even at minor recreational doses, include increased muscle activity (such as bruxism, restless legs, and jaw clenching), hyperactivity, insomnia, difficulty concentrating and feelings of restlessness.Treatment of MDMA overdose:Emphasis should be on maintaining the airway along with the stabilization of breathing and circulation.Patients may present obtunded due to hyponatremia requiring endotracheal intubation.For the hyperthermic patient, evaporative cooling along with ice packs to the groin and axilla are beneficial.Patients who present in severe toxicity within one hour of ingestion can receive activated charcoal PO or via an NG tube. Antipyretics, such as acetaminophen, should be avoided as they have no role and can worsen an already compromised liver.
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This question is part of the following fields:
- Medicine
- Pharmacology
-
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Question 106
Incorrect
-
Defects in chromosomal structure (and examples) include those mentioned below except:
Your Answer:
Correct Answer: Lyonization (x-linked disorders)
Explanation:All are true except for A) Lyonization which is the inactivation of the X chromosomes in a female. It is not a chromosomal abnormality.
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This question is part of the following fields:
- Genetics
- Medicine
-
-
Question 107
Incorrect
-
Intrinsic Factor is released by,
Your Answer:
Correct Answer: Parietal cell
Explanation:Intrinsic factor (IF), also known as gastric intrinsic factor (GIF), is a glycoprotein produced by the parietal cells of the stomach. It is necessary for the absorption of vitamin B12 (cobalamin) later on in the small intestine.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 108
Incorrect
-
Lipid- lowering drugs like Lovastatin reduce cholesterol synthesis by inhibiting which enzyme?
Your Answer:
Correct Answer: HMG-CoA reductase
Explanation:Statins, also known as HMG-CoA reductase inhibitors, are a class of lipid-lowering medications. Statins have been found to reduce cardiovascular disease (CVD) and mortality in those who are at high risk.
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This question is part of the following fields:
- Medicine
- Metabolism
-
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Question 109
Incorrect
-
A 45 year old man presents with fever, malaise, weight loss and myalgias that have been occurring for a month. You suspect polyarteritis nodosa and arrange for some lab investigations. Which of the following abnormality would most likely be present?
Your Answer:
Correct Answer: Elevated creatinine
Explanation:People with polyarteritis nodosa often exhibit anaemia of chronic disease. Leucocytosis and eosinophilia may also be present. ANCA is only rarely positive. As polyarteritis nodosa affects the kidneys as well, the creatinine is elevated in most cases.
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This question is part of the following fields:
- Connective Tissue
- Medicine
-
-
Question 110
Incorrect
-
The oligosaccharidases responsible for further digestion of starch after breakdown by the above mentioned enzymes is located where?
Your Answer:
Correct Answer: Brush border of small intestine
Explanation:The final step in digestion of carbohydrates, which is conversion of disaccharides to absorbable monosaccharides occurs on the small intestinal epithelial cells. The enzymes responsible for this final stage of digestion are not freely found in the intestinal lumen, but they are found as integral membrane proteins in the plasma membrane of the epithelial cell. The apical plasma membrane of the intestinal epithelial cell has numerous microvilli known as the brush border. Thus, the enzymes embedded in those microvilli are referred to as brush border enzymes.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 111
Incorrect
-
Which enzyme facilitates the function of pancreatic lipase by increasing exposure of its active site?
Your Answer:
Correct Answer: Colipase
Explanation:Colipase is a co enzyme that optimize the activity of lipase by facilitating the exposure of its active sites.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 112
Incorrect
-
Depolarization of the T tubule membrane activates the sarcoplasmic reticulum via which receptors?
Your Answer:
Correct Answer: Dihydropyridine receptors
Explanation:Action potentials are transmitted to the fibrils of a fiber through the T tubule system. It triggers the release of Ca 2+ form the terminal cisterns. Depolarization of the T tubules activates the sarcoplasmic reticulum through the dihydropyridine receptors.
Dihydropyridine receptors (DHPRs), are voltage-gated Ca2+ channels, and ryanodine receptors (RyRs), which are intracellular Ca2+ release channels, are expressed in diverse cell types, including skeletal and cardiac muscle.
Ryanodine receptors (RyRs) are located in the sarcoplasmic/endoplasmic reticulum membrane and are responsible for the release of Ca2+ from intracellular stores during excitation-contraction coupling in both cardiac and skeletal muscle.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 113
Incorrect
-
A 78 year old woman presents to the clinic complaining of left sided temporal headaches and jaw claudication that has been going on for a month. A left temporal artery biopsy is negative. Results show:Hb: 130g/lPlatelets: 359*109/lWBC: 10*109/lCRP: 89mg/lWhich of the following options would be the next best step in the management of this patient?
Your Answer:
Correct Answer: Commence prednisolone
Explanation:Temporal arteritis is a chronic large- and medium-sized vessel vasculitis that typically involves the temporal arteries. Classical symptoms include temporal headaches, jaw claudication, amaurosis fugax. Physical exam shows scalp tenderness, palpation of the temporal area may demonstrate an absent pulse, knot-like swelling and vision loss. Lab results reveal an increased erythematous sedimentation rate and C-reactive protein. Temporal artery biopsy confirms the diagnosis. Management approach: high-dose systemic corticosteroids should be promptly administered even before the diagnosis is established. Temporal artery biopsy confirms the diagnosis. Inability to manage this or administer glucocorticoids might lead to development of blindness.
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This question is part of the following fields:
- Connective Tissue
- Medicine
-
-
Question 114
Incorrect
-
Which part of the neuron has the highest concentration of sodium channels per square millimetre of the cell membrane?
Your Answer:
Correct Answer: Nodes of Ranvier
Explanation:The nodes of Ranvier contain Na+/K+ ATPases, Na+/Ca2+ exchangers and a high density of Na+ channels. The estimated concentration of sodium channels in the node is of ∼1500/μm2.
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This question is part of the following fields:
- Medicine
- Neurology
-
-
Question 115
Incorrect
-
The transport of the di- and tri-peptides into enterocytes is by:
Your Answer:
Correct Answer: H+ dependent peptide transporter 1
Explanation:Peptides longer that four amino acids are not absorbed. There is abundant absorption of di and tri peptidases in the small intestine. They are absorbed into the epithelial cell of the small intestine via a transporter called Peptide Transporter 1 by co transport with H+ ions.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 116
Incorrect
-
Question 117
Incorrect
-
A 79-year-old woman has a waddling gait. History reveals enuresis and change in behaviour. What is the most likely diagnosis?
Your Answer:
Correct Answer: Normal pressure hydrocephalus
Explanation:The waddling gait and behaviour change are attributes of normal pressure hydrocephalus along with loss of bladder control which commonly happens with elder age.
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This question is part of the following fields:
- Geriatrics
- Medicine
-
-
Question 118
Incorrect
-
Which of the following is not true regarding mitochondrial chromosome disorders?
Your Answer:
Correct Answer: Because mitochondrial chromosomes have no introns in their genes, any point mutation has a low likelihood of having an effect.
Explanation:Mitochondrial DNA (mtDNA) does indeed lack introns, meaning that its genes are closely packed with coding sequences. This actually means that any point mutation in the mtDNA is more likely to have an effect, not less. The lack of introns means there are fewer non-coding regions where mutations can occur without affecting gene function. Thus, mutations in mtDNA often have significant consequences because they are more likely to alter essential coding sequences.
The other statements are true:
- Most mitochondrial diseases are myopathies and neuropathies with a maternal pattern of inheritance: This is correct because mtDNA is inherited maternally, and many mitochondrial disorders affect muscle and nerve function.
- Retinal degeneration, diabetes mellitus, and some forms of hearing loss are some of the other diseases attributed to mitochondrial chromosome defects: These are indeed conditions associated with mitochondrial defects.
- Mitochondrial chromosome defects are inherited from one’s mother: This is correct, as mtDNA is passed from mother to offspring.
- Leber’s hereditary optic neuropathy (LHON), the commonest cause of blindness in young men, is an example of a mitochondrial chromosome defect: This is true; LHON is a well-known mitochondrial disorder.
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This question is part of the following fields:
- Genetics
- Medicine
-
-
Question 119
Incorrect
-
Calcium induced calcium release occurs in the sarcoplasmic reticulum by activation of which receptors
Your Answer:
Correct Answer: Ryanodine receptors
Explanation:Calcium-induced calcium release (CICR) describes a biological process whereby calcium is able to activate calcium release from intracellular Ca2+ stores (e.g., endoplasmic reticulum or sarcoplasmic reticulum). CICR occurs when the resulting Ca2+ influx activates ryanodine receptors on the SR membrane, which causes more Ca2+ to be released into the cytosol.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 120
Incorrect
-
The neurotransmitter utilised by the Purkinje cells is:
Your Answer:
Correct Answer: GABA
Explanation:The cerebellar cortex consist of 3 layers: the molecular layer, the granular cell layer and the Purkinje cell layer. Purkinje cells play a fundamental role in controlling motor movement. They release a neurotransmitter called GABA (gamma-aminobutyric acid) which exerts inhibitory actions thereby reducing transmission of impulses. These inhibitory functions enable purkinje cells to regulate and coordinate motor movements.
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This question is part of the following fields:
- Medicine
- Neurology
-
-
Question 121
Incorrect
-
Which of the following stimulates glucagon release?
Your Answer:
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
-
-
Question 122
Incorrect
-
Which two ducts form the ampulla of Vater?
Your Answer:
Correct 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 123
Incorrect
-
Regarding Iron stores, which of the following contains the highest proportion of total body iron?
Your Answer:
Correct Answer: Haemoglobin
Explanation:Most well-nourished people in industrialized countries have 4 to 5 grams of iron in their bodies. Of this, about 2.5 g is contained in the haemoglobin needed to carry oxygen through the blood, and most of the rest (approximately 2 grams in adult men, and somewhat less in women of childbearing age) is contained in ferritin complexes that are present in all cells, but most common in bone marrow, liver, and spleen.
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This question is part of the following fields:
- Haematology
- Medicine
-
-
Question 124
Incorrect
-
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
-
-
Question 125
Incorrect
-
Which one of the following interventions has the least role in management of acne rosacea?
Your Answer:
Correct 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
-
-
Question 126
Incorrect
-
Which of the following phases in depolarization and repolarization of cardiac muscle cells are caused by the inactivation of Na+ channels?
Your Answer:
Correct Answer: Phase 1 : rapid repolarization
Explanation:Phase 0 is caused by the sodium current. Voltage gated sodium channels open leading to the influx of sodium into the cardiac muscle cell. Phase 1 is the rapid transient repolarization phase which is caused by the inactivation of the voltage gated sodium channels and opening of the voltage gated potassium channels along with opening of the slow calcium channels. Phase 2 which is the plateau is caused by opening of the slow calcium channels. Phase 4 is caused by closing of the slow calcium channels and opening of the potassium channels leading to efflux of potassium leading to the establishment of the resting membrane potential.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 127
Incorrect
-
Which of the following is NOT a pancreatic enzyme?
Your Answer:
Correct Answer: Pepsinogen 1
Explanation:Pancreatic juice, composed of the secretions of both ductal and acinar cells, is made up of the following digestive enzymes:Trypsinogen, which is an inactive(zymogenic) protease that, once activated in the duodenum into trypsin, breaks down proteins at the basic amino acids. Trypsinogen is activated via the duodenal enzyme enterokinase into its active form trypsin.Colipase is a protein co-enzyme required for optimal enzyme activity of pancreatic lipase. It is secreted by the pancreas in an inactive form, procolipase, which is activated in the intestinal lumen by trypsin.Chymotrypsinogen, which is an inactive (zymogenic) protease that, once activated by duodenal enterokinase, breaks down proteins at their aromatic amino acids. Chymotrypsinogen can also be activated by trypsin.Carboxypeptidase, which is a protease that takes off the terminal amino acid group from a proteinSeveral elastases that degrade the protein elastin and some other proteins.Pancreatic lipase that degrades triglycerides into fatty acids and glycerol.Sterol esterasePhospholipaseSeveral nucleases that degrade nucleic acids, like DNase and RNase.Pancreatic amylase that breaks down starch and glycogen which are alpha-linked glucose polymers.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
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Question 128
Incorrect
-
Where on the surface of the chest is the normal site of auscultation for the mitral area?
Your Answer:
Correct Answer: 4th left intercostal space in the mid-clavicular line
Explanation:The mitral valve is situated in the left 4th intercostal space just beneath the sternum, in the mid clavicular line.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 129
Incorrect
-
Myocyte action potentials – Choose the false statement:
Your Answer:
Correct Answer: Repolarisation is due to net k+ influx
Explanation:Final repolarization (phase 3) to the resting membrane potential (phase 4) is due to closure of the Ca2+ channels and a slow, delayed increase of K+ efflux through various types of K+ channels.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 130
Incorrect
-
A 75 year old man was brought to the clinic by his wife because lately he has lost interest in activities he previously enjoyed. His wife is worried and claims he's generally withdrawn. What would exclude depression in favour of dementia?
Your Answer:
Correct Answer: Urinary incontinence
Explanation:Urinary incontinence is not a usual symptom of depression. A depressed patient is usually capable of maintaining control of his body sphincters. In dementia, however, urinary incontinence is an important and late symptom of the disease, non-related to any urinary tract pathology. It is rather related to the cognitive impairment caused by dementia.
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This question is part of the following fields:
- Geriatrics
- Medicine
-
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Question 131
Incorrect
-
Treatment of an acute attack of gout with allopurinol may result in which of the following?
Your Answer:
Correct Answer: Exacerbation and prolongation of the attack
Explanation:Initiation of allopurinol treatment during an attack can exacerbate and prolong the episode. Thus treatment should be delayed until the attack resolves.
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This question is part of the following fields:
- Medicine
- Pharmacology
-
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Question 132
Incorrect
-
A 23 year old man presents with a painful right elbow and left Achilles tendon. He also gives history of dysuria, fever and conjunctivitis. Examination reveals macules and pustules on his hands. He has returned from a trip to Far East 3 weeks ago and admits to having unprotected sex. Which of the following is the most likely diagnosis?
Your Answer:
Correct Answer: Reactive arthritis
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. extraarticular dermatologic manifestations include skin lesions of the glans resembling psoriasis (balanitis circinata); hyperkeratinisation of the palms and soles (keratoderma blenorrhagicum), oral ulcers. Other STDs including HIV, syphilis have different presentations. Psoriatic arthritis is not commonly associated with urethritis and conjunctivitis.
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This question is part of the following fields:
- Connective Tissue
- Medicine
-
-
Question 133
Incorrect
-
One of the functions of the spleen with regards to red blood cells is:
Your Answer:
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 134
Incorrect
-
Which of the following is correct regarding lead poisoning?
Your Answer:
Correct Answer: Causes a peripheral neuropathy due to demyelination
Explanation:Lead can be absorbed through the skin and by inhalation. It is associated with iron deficiency and a microcytic anaemia. The most common gastrointestinal symptoms are abdominal colic and constipation.
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This question is part of the following fields:
- Medicine
- Pharmacology
-
-
Question 135
Incorrect
-
How does pregnancy affect the cardiac output of a patient?
Your Answer:
Correct Answer: Increased cardiac output due to increase in heart rate and stroke volume
Explanation:Cardiac Output increases to a similar degree as the blood volume. During the first trimester cardiac output is 30-40% higher than in the non-pregnant state. Steady rises are shown on Doppler echocardiography, from an average of 6.7 litres/minute at 8-11 weeks to about 8.7 litres/minute flow at 36-39 weeks; they are due, primarily, to an increase in stroke volume (35%) and, to a lesser extent, to a more rapid heart rate (15%). There is a steady reduction in systemic vascular resistance (SVR) which contributes towards the hyperdynamic circulation observed in pregnancy
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 136
Incorrect
-
Select the CORRECT statement regarding bile salts…
Your Answer:
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
-
-
Question 137
Incorrect
-
Hydroxyl radicals are broken down by which of the following substance?
Your Answer:
Correct Answer: Antioxidants
Explanation:Unlike superoxide, which can be detoxified by superoxide dismutase, the hydroxyl radical cannot be eliminated by an enzymatic reaction but it is believed can be counteracted by antioxidants.
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This question is part of the following fields:
- Cell Biology
- Medicine
-
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Question 138
Incorrect
-
Amino acid reabsorption occurs most markedly in the?
Your Answer:
Correct Answer: Proximal convoluted tubule
Explanation:Renal protein reabsorption is the part of renal physiology that deals with the retrieval of filtered proteins, preventing them from disappearing from the body through the urine. Almost all reabsorption takes place in the proximal tubule. Only ,1% is left in the final urine.
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This question is part of the following fields:
- Medicine
- Renal
-
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Question 139
Incorrect
-
Sympathetic supply to the stomach is derived from
Your Answer:
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
-
-
Question 140
Incorrect
-
When one of the two copies of the autosomes has a mutation and the protein produced by the normal form of the gene cannot compensate. The affected individual has an:
Your Answer:
Correct Answer: Autosomal dominant disorder
Explanation:An autosomal dominant trait will be expressed no matter the consequence. If one chromosome has a mutation the other will not be able to compensate for the mutation hence the protein formed will be mutated and will not function properly.
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This question is part of the following fields:
- Genetics
- Medicine
-
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Question 141
Incorrect
-
A 50-year-old man is admitted with nausea and excessive drowsiness after taking an antihistamine tablet with grapefruit juice. Which of the following liver enzyme systems is affected by grapefruit juice causing the given side effect?
Your Answer:
Correct Answer: Cytochrome p450 3A4
Explanation:The cytochrome p450 3A4 enzyme system in the liver is affected by grapefruit juice. Patients taking antihistamines should be advised to avoid drinking grapefruit juice. This is because constituents of grapefruit juice such as naringin and bergamottin inhibit CYP3A4 in the liver, particularly at high doses, leading to decreased drug elimination via hepatic metabolism and can increase potential drug toxicities. Inhibition of this enzyme system leads to reduced metabolism of antihistamines leading to an increased incidence of side effects like excessive drowsiness and nausea as in this patient.
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This question is part of the following fields:
- Medicine
- Pharmacology
-
-
Question 142
Incorrect
-
The blood supply to the greater curvature of the stomach is via the:
Your Answer:
Correct Answer: Right and left gastro-epiploic arteries
Explanation:The blood supply to the greater curvature of the stomach is via the left and the right gastro-epiploic arteries branching from the splenic artery near the hilum.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 143
Incorrect
-
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
-
-
Question 144
Incorrect
-
A 85 year old male with a history of faecal impaction, who lived at a nursing-home presented with abdominal pain and distension, confusion and agitation. Which of the following is the first step of the management.
Your Answer:
Correct Answer: Phosphate enema
Explanation:The most probable cause for this presentation is faecal impaction following constipation, which is common among old people who live in nursing-homes. There can be number of reason for constipation in old age, including medications, endocrine and metabolic diseases, neurologic disorders, myopathic disorders, dietary habits etc. Enemas are a way of removing impacted faeces, which helps rectal evacuation.
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This question is part of the following fields:
- Geriatrics
- Medicine
-
-
Question 145
Incorrect
-
The immunoglobulin found in the highest concentration in humans is
Your Answer:
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
-
-
Question 146
Incorrect
-
The pathogen in variant Creutzfeldt Jacobs disease is an example of a:
Your Answer:
Correct Answer: Prion
Explanation:Types of Creutzfeldt Jacobs Disease (CJD) include:1. variant – This is thought to be caused by the consumption of food contaminated with prions, which also cause BSE.2. sporadic – This accounts for 85% of cases of CJD. 3. familial – This accounts for the majority of the other 15% cases of CJD.4. iatrogenic – This form of CJD arises from contamination with tissue from an infected person, usually as the result of a medical procedure.
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This question is part of the following fields:
- Infectious Diseases
- Medicine
-
-
Question 147
Incorrect
-
Which is the commonest cardiovascular abnormality seen in an adult patient with Marfan’s syndrome?
Your Answer:
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
-
-
Question 148
Incorrect
-
Which of the following is a form of synaptic plasticity?
Your Answer:
Correct Answer: Working memory
Explanation:Synaptic plasticity is an important neurochemical foundation of working memory and generation of memory. Synaptic plasticity is the ability of synapses to strengthen or weaken over time in response to increases or decreases in their activity.
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This question is part of the following fields:
- Medicine
- Neurology
-
-
Question 149
Incorrect
-
Changes in cadherin expression are associated with
Your Answer:
Correct Answer: Tumour metastatic potential
Explanation:Cadherins play a role in maintaining cell and tissue structure, and in cellular movement. The E-cadherin–catenin complex plays a key role in cellular adhesion; loss of this function has been associated with greater tumour metastasis.
-
This question is part of the following fields:
- Cell Biology
- Medicine
-
-
Question 150
Incorrect
-
Choose the most correct answer, what reduces affinity for oxygen in haemoglobin?
Your Answer:
Correct Answer: All the options are true
Explanation:The strength with which oxygen binds to haemoglobin is affected by several factors. These factors shift or reshape the oxyhaemoglobin dissociation curve. A rightward shift indicates that the haemoglobin under study has a decreased affinity for oxygen. The causes of shift to right can be remembered using the mnemonic, CADET, face Right! for CO2 and CO, Acid (H+), 2,3-DPG, Exercise and Temperature.
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This question is part of the following fields:
- Haematology
- Medicine
-
-
Question 151
Incorrect
-
Regarding cardiac muscle contractility, the afterload refers to:
Your Answer:
Correct Answer: The resistance against which blood is expected
Explanation:The afterload for the left ventricle is the aortic pressure. Hence it is this pressure that offers resistance against which the blood is to be expelled from the heart.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 152
Incorrect
-
Question 153
Incorrect
-
The interventricular septum is supplied anteriorly by the?
Your Answer:
Correct Answer: Left anterior descending artery
Explanation:The anterior interventricular artery or left anterior descending artery supplies the anterior 2/3rds of the interventricular septum.
-
This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 154
Incorrect
-
Which neuron secretes glutamate as its neurotransmitter?
Your Answer:
Correct Answer: A delta and C pain fibers
Explanation:A delta and C fibers use glutamate as their primary neurotransmitter where it acts as a fast acting localized neurotransmitter.
-
This question is part of the following fields:
- Medicine
- Neurology
-
-
Question 155
Incorrect
-
The ATPase of parietal cells moves:
Your Answer:
Correct Answer: H+ into the gastric lumen in exchange for a k+
Explanation:ATPase of the parietal cell is also known as the proton pump, which moves H+ ions into the gastric lumen in exchange for K+ ions into the cell.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 156
Incorrect
-
Question 157
Incorrect
-
The coronary arteries supply which part of the heart’s subendocardial region exclusively in diastole?
Your Answer:
Correct Answer: Left ventricle
Explanation:It is only during diastole that the blood flows to the subendocardial portion of the left ventricle, as the heart muscle relaxes and the coronary arteries regain their patency.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 158
Incorrect
-
Which cells secrete insulin?
Your Answer:
Correct Answer: B cells of the pancreatic islets
Explanation:Insulin is synthesised and stored by the B cells of the pancreatic islets (70% of islet cells), glucagon is synthesised and stored in the A cells (20%) and somatostatin is synthesised and stored in the D cells (10%).
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This question is part of the following fields:
- Endocrinology
- Medicine
-
-
Question 159
Incorrect
-
A 18-year-old female is brought to the emergency department by her boyfriend. He is concerned that she may have taken an overdose of her mom's morphine sulphate pills after being depressed about her mother, who is dying of carcinoma of the breast.Which of the following may point towards his suspicion?
Your Answer:
Correct Answer: Sweating
Explanation:Excessive sweating points towards a morphine overdose.Morphine is considered the classic opioid analgesic with which other painkillers are compared. Like other medications in this class, morphine has an affinity for delta, kappa, and mu-opioid receptors.Most commonly used in pain management, morphine provides major relief to patients afflicted with pain.Among the more common adverse effects of morphine use is constipation. Other side effects include nausea, vomiting, drowsiness, and confusion. Psychological and physical dependence may occur.Other side effects include bronchospasm, angioedema, urinary retention, ureteric or biliary spasm, dry mouth, sweating, rash, facial flushing, vertigo, tachycardia, bradycardia, palpitations, orthostatic hypotension, hypothermia, restlessness, mood change, hallucinations, seizures (adults and children) and miosis, headache and allergic reactions (including anaphylaxis) and decreased libido or potency.Raised intracranial pressure occurs in some patients. Muscle rigidity may occur with high doses. Elevated liver enzymes may occur due to biliary sphincter constriction. Large doses can lead to respiratory depression, circulatory failure, and coma.Treatment of opioid overdose:Initial treatment of overdose begins with supportive care.Naloxone is a pure competitive antagonist of opiate receptors and has no agonistic activity. The drug is relatively safe and can be administered intravenous, intramuscular, subcutaneous or via the endotracheal tube.Alternatively, nalmefene and naltrexone maybe considered.
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This question is part of the following fields:
- Medicine
- Pharmacology
-
-
Question 160
Incorrect
-
Which of the following statements is not true about mitochondrial chromosomes?
Your Answer:
Correct Answer: Mitochondrial chromosomes play no role in the transmission of disease from generation to generation.
Explanation:All the above mentioned statements are true except that mitochondrial DNA is passed from the mother to the child. If the child inherits the defective mitochondrial gene it will manifest some form of the disease. Commonly inherited diseases related to mitochondrial abnormality are Leber hereditary optic neuropathy and myoclonic epilepsy with ragged red fibers (MERRF).
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This question is part of the following fields:
- Genetics
- Medicine
-
-
Question 161
Incorrect
-
Which is primarily responsible for the conversion of T4 to T3 in the periphery?
Your Answer:
Correct Answer: Deiodinase 1
Explanation:Type 1 iodothyronine deiodinase, also known simply as deiodinase 1, is an enzyme which can produce both triiodothyronine (active form) or inactivate metabolites from T4. It is responsible for almost 80% of the conversion of peripheral T4 to T3. Iodothyronine deiodinases are not to be confused with iodotyrosine deiodinases, which are also part of the deiodinase enzymes.
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This question is part of the following fields:
- Endocrinology
- Medicine
-
-
Question 162
Incorrect
-
An important enzyme in renal tissue responsible for the conversion of glutamine to glutamate and the subsequent production of NH4 is called?
Your Answer:
Correct Answer: Glutaminase
Explanation:Glutaminase catalyses the following reaction:Glutamine + H2O → Glutamate + NH3
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This question is part of the following fields:
- Medicine
- Renal
-
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Question 163
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 164
Incorrect
-
What is the isolated effect of B2 stimulation on the coronaries?
Your Answer:
Correct Answer: Vasodilatation
Explanation:Norepinephrine and epinephrine are agonists for all adrenergic receptor subtypes, although with varying affinities. Based on their physiology and pharmacology, adrenergic receptors have been divided into two principal types: alpha and beta. These types have been further differentiated into alpha-1, alpha-2, b1, and b2 receptors.
Alpha-1 Receptors are located on postsynaptic cells in smooth muscle and elicit vasoconstriction.
Alpha-2 receptors are localized on presynaptic membranes of postganglionic nerve terminals that synthesize norepinephrine. When activated by catecholamines, alpha-2 receptors act as negative feedback controllers, inhibiting further norepinephrine release.
Activation of myocardial b1 receptors stimulates the rate and strength of cardiac contraction, and consequently increases cardiac output. b1 Receptor activation also stimulates renin release from the kidney. Another class of antihypertensive agents acts by inhibiting b1 receptors.
Activation of b2 receptors by epinephrine relaxes vascular smooth muscle and results in vasodilation.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 165
Incorrect
-
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
-
-
Question 166
Incorrect
-
The cell membrane:
Your Answer:
Correct Answer: Is a bilayer of amphipathic lipids
Explanation:The cell membrane consists of a bilayer of amphipathic lipids with embedded proteins. The basic function of the cell membrane is to protect the cell from its surroundings. It is selectively permeable to ions and organic molecules. The entire membrane is held together via non-covalent interaction of hydrophobic tails, however the structure is quite fluid and not fixed rigidly in place. Membranes are typically 7.5–10 nm in thickness and typically have a large content of proteins, around 50% of membrane volume.
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This question is part of the following fields:
- Cell Biology
- Medicine
-
-
Question 167
Incorrect
-
The parietal cells of the stomach secrete which of the following?
Your Answer:
Correct Answer: Hydrochloric acid
Explanation:Parietal cells are the epithelial cells that secrete hydrochloric acid (HCl) and intrinsic factor. These cells are located in the gastric glands found in the lining of the fundus and in the body of the stomach.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 168
Incorrect
-
A 67 year old man reports weight loss. Labs show a raised alkaline phosphatase at 290 U/L (normal range 35-120). Plain radiographs reveal sclerotic lesions of the bone. Which of the following is the most likely cause of these findings?
Your Answer:
Correct Answer: Prostate cancer
Explanation:Osteoblastic (or sclerotic) bony metastases, characterized by deposition of new bone, present in prostate cancer, carcinoid, small cell lung cancer, Hodgkin lymphoma or medulloblastoma. The other cancers listed in the options are osteolytic.
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This question is part of the following fields:
- Connective Tissue
- Medicine
-
-
Question 169
Incorrect
-
Question 170
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:
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
-
-
Question 171
Incorrect
-
Which of the following features occurs very less frequently with drug induced lupus?
Your Answer:
Correct Answer: Glomerulonephritis
Explanation:Drug induced lupus typically presents with pulmonary involvement and no renal or neurological involvement. Hence glomerulonephritis would be highly unlikely in this case. Rash and arthralgias are classic presentations. Pleurisy can be present as pulmonary involvement may occur with DILE.
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This question is part of the following fields:
- Connective Tissue
- Medicine
-
-
Question 172
Incorrect
-
Which of these vitamins is not found in plants?
Your Answer:
Correct Answer: Vitamin B12
Explanation:No fungi, plants, nor animals (including humans) are capable of producing vitamin B12. Only bacteria and archaea have the enzymes needed for its synthesis. Proved food sources of B12 are animal products (meat, fish, dairy products).
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This question is part of the following fields:
- Haematology
- Medicine
-
-
Question 173
Incorrect
-
The premotor cortex is:
Your Answer:
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
-
-
Question 174
Incorrect
-
The ependyma fuse with which of the following to from the choroid plexus?
Your Answer:
Correct Answer: Tela choroidea
Explanation:The choroid plexus produces the cerebrospinal fluid (CSF) in the ventricles of the brain. It consists of modified ependymal cells. Tela choroidea is a region of pia mater of the meninges and underlying ependyma that’s a part of the choroid plexus. It is a very thin layer of the connective tissue of pia mater that overlies and covers the ependyma.
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This question is part of the following fields:
- Medicine
- Neurology
-
-
Question 175
Incorrect
-
Majority of gastrinomas are found in the:
Your Answer:
Correct Answer: Duodenum
Explanation:A gastrinoma is a tumour in the pancreas or duodenum that secretes excess of gastrin leading to ulceration in the duodenum, stomach and the small intestine. It is usually found in the duodenum, although it may arise in the stomach or pancreas. Those occurring in the pancreas have a greater potential for malignancy. Most gastrinomas are found in the gastrinoma triangle; this is bound by the junction of cystic and common bile ducts, junction of the second and third parts of the duodenum, and the junction of the neck and body of the pancreas.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 176
Incorrect
-
Regarding blood supply to the heart;
Your Answer:
Correct Answer: Coronary arteries fill as the heart relaxes
Explanation:The heart muscles acts like the skeletal muscle in the fact that it also compress the vessels during contraction. As the pressure in the ventricle is slightly greater than in the aorta the coronary vessels collapse during systole. Blood flows through them during the diastole phase of contraction.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 177
Incorrect
-
Which lipoprotein contains the most cholesterol esters?
Your Answer:
Correct Answer: LDL
Explanation:LDL and HDL transport both dietary and endogenous cholesterol in the plasma, but LDL is the main transporter of cholesterol and cholesteryl esters.
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This question is part of the following fields:
- Medicine
- Metabolism
-
-
Question 178
Incorrect
-
Bile contains:
Your Answer:
Correct Answer: Bile acids, phosphatidylcholine, cholesterol
Explanation:The main components of bile include bile acids or bile salts, phospholipids; mainly phosphatidylcholine, cholesterol, bilirubin, inorganic salts; potassium, sodium and bicarbonate.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 179
Incorrect
-
H+ ions used in the production of acid by parietal cells is produced with the help of which enzyme?
Your Answer:
Correct Answer: Carbonic anhydrase ii
Explanation:Carbonic anhydrase enzyme catalyses the rapid interconversion of carbon dioxide and water to bicarbonate and protons (or vice versa). This is a reversible reaction that takes place in the gastric parietal cells.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 180
Incorrect
-
On a mountain the atmospheric pressure is 700 mmHg and the humidity close to zero, the partial pressure of oxygen is:
Your Answer:
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
-
-
Question 181
Incorrect
-
Lymphoid stem cells give rise to the following cells:
Your Answer:
Correct Answer: T cells, b cells and natural killer cells
Explanation:T Cells, B Cells and NK Cells (and all other Innate lymphoid cells) are unique to the lymphocyte family, but dendritic cells are not. Dendritic cells of identical appearance but different markers are spread throughout the body, and come from either lymphoid and myeloid lineages.
Myeloid stem cells lead to myeloblasts, which evolve into macrophages, monocytes, neutrophils, basophils, and eosinophils.
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This question is part of the following fields:
- Haematology
- Medicine
-
-
Question 182
Incorrect
-
Which serotonergic receptor is associated with vomiting?
Your Answer:
Correct Answer: 5ht3
Explanation:5ht3 is a receptor strongly associated with vomiting, present in vagal afferents, the solitary tract nucleus (STN), and the area posterior. For this reason, 5ht3 antagonists are commonly used as antiemetic drugs. They include ondansetron, tropisetron, and granisetron.
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This question is part of the following fields:
- Medicine
- Neurology
-
-
Question 183
Incorrect
-
The approximate incidence of deep venous thrombosis (DVT) in the general population each year is:
Your Answer:
Correct Answer: 1 per 1000
Explanation:About 1 in 1000 adults per year has DVT, but as of 2011, available data is dominated by North American and European populations. DVT is rare in children, with an incidence of about 1 in 100,000 a year. From childhood to old age, incidence increases by a factor of about 1000, with almost 1% of the elderly experiencing DVTs yearly.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 184
Incorrect
-
Concerning surface anatomy, where is the aortic valve found?
Your Answer:
Correct Answer: Situated in the left third intercostal space underneath the sternum
Explanation:The aortic valve is situated in the left 3rd intercostal space just beneath the sternum.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 185
Incorrect
-
Where is the site of action of spironolactone?
Your Answer:
Correct Answer: Distal convoluted tubule
Explanation:Spironolactone is an aldosterone antagonist which acts in the distal convoluted tubule. It is a potassium-sparing diuretic that prevents the body from absorbing too much salt and keeps the potassium levels from getting too low. Spironolactone is used to treat heart failure, high blood pressure (hypertension), or hypokalaemia (low potassium levels in the blood).
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This question is part of the following fields:
- Medicine
- Pharmacology
-
-
Question 186
Incorrect
-
A 75-year-old man has presented to the clinic with a complaint of disturbed sleep. The physician has prescribed temazepam. Which of the following best describes the mechanism of action of this drug?
Your Answer:
Correct Answer: Enhances the effect of gamma-aminobutyric acid
Explanation:Temazepam is an orally available benzodiazepine used in the therapy of insomnia. The soporific activity of the benzodiazepines is mediated by their ability to enhance gamma-aminobutyric acid (GABA) mediated inhibition of synaptic transmission through binding to the GABA-A receptor.The recommended initial dose for insomnia is 7.5 mg before bedtime, increasing as needed to a maximum dose of 30 mg. The most common side effects of temazepam are dose-related and include daytime drowsiness, lethargy, ataxia, dysarthria, and dizziness.Tolerance develops to these side effects, but tolerance may also develop to the effects on insomnia.
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This question is part of the following fields:
- Medicine
- Pharmacology
-
-
Question 187
Incorrect
-
The postextrasystolic potentiation of myocardial contractility is due to:
Your Answer:
Correct Answer: Increase in intracellular Ca2+
Explanation:The postextrasystolic potentiation of myocardial contractility Is not due to ventricular filling. It occurs in isolated locations in the heart and is due to increase availability of intracellular calcium.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 188
Incorrect
-
A 47-year-old male with type II diabetes mellitus presents to your clinic with a history suggestive of erectile dysfunction. You decide to start him on sildenafil citrate. What is the mechanism of action of this drug?
Your Answer:
Correct Answer: Phosphodiesterase type V inhibitor
Explanation:Sildenafil (Viagra) is a phosphodiesterase type V inhibitor used in the treatment of impotence.Contraindications:- Patients taking nitrates and related drugs such as nicorandil- Hypotension- Recent stroke or myocardial infarction (NICE recommend waiting 6 months)Side-effects:Visual disturbances e.g. cyanopsia, non-arthritic anterior ischaemic NeuropathyNasal congestionFlushingGastrointestinal side-effectsHeadache
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This question is part of the following fields:
- Medicine
- Pharmacology
-
-
Question 189
Incorrect
-
Free radicals are best defined by which of the following statements.
Your Answer:
Correct 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
-
-
Question 190
Incorrect
-
Which of the following diseases have antibodies available for treatment of the condition.
Your Answer:
Correct Answer: None of these
Explanation:There is no specific treatment for hepatitis A. Recovery from symptoms following infection may be slow and may take several weeks or months. The hepatitis A vaccine is effective for prevention and appears to be effective for life.Acute hepatitis B infection does not usually require treatment and most adults clear the infection spontaneously. Early antiviral treatment may be required in fewer than 1% of people, whose infection takes a very aggressive course (fulminant hepatitis) or who are immunocompromised. Although none of the available drugs can clear the infection, they can stop the virus from replicating, thus minimizing liver damage.There is no specific treatment for measles. Most people with uncomplicated measles will recover with rest and supportive treatment. In developed countries, children are immunized against measles at 12 months, generally as part of a three-part MMR vaccine (measles, mumps, and rubella). The vaccination is generally not given before this age because such infants respond inadequately to the vaccine due to an immature immune system. Treatment after rabies exposure can prevent the disease if administered promptly, generally within 10 days of infection. The Centres for Disease Control and Prevention recommends people receive one dose of human rabies immunoglobulin (HRIG) and four doses of rabies vaccine over a 14-day period.
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This question is part of the following fields:
- Infectious Diseases
- Medicine
-
-
Question 191
Incorrect
-
The interior of lysosomes is kept at a pH of around 5 by the action of:
Your Answer:
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
-
-
Question 192
Incorrect
-
Carcinogens found in cigarette smoke can transform proto-oncogenes to oncogenes through:
Your Answer:
Correct Answer: Point mutations in genomic DNA
Explanation:80% of the pancreatic cancers are environmentally influenced by smoking which increases the risk by 50%. Mutation can occur in the KRAS, p16, SMAD4, and TP53 genes among other tumour suppression genes. Smoking can be implicated in transformation of all these genes. Apart from KRAS all the genes are inactivated in pancreatic cancer. As KRAS is the most commonly altered gene, mutation occurs as point mutation. As smoking is the most common aetiology in pancreatic cancer, and KRAS is the most important gene that is altered. Most commonly cigarette smoke causes point mutation.
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This question is part of the following fields:
- Genetics
- Medicine
-
-
Question 193
Incorrect
-
Where is thyroglobulin produced?
Your Answer:
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
-
-
Question 194
Incorrect
-
Iron absorption occurs primarily in which part of the GIT?
Your Answer:
Correct Answer: Duodenum
Explanation:Like most mineral nutrients, the majority of the iron absorbed from digested food or supplements is absorbed in the duodenum by enterocytes of the duodenal lining.
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This question is part of the following fields:
- Haematology
- Medicine
-
-
Question 195
Incorrect
-
A 72-year-old with varicose veins complains of swollen, red, itchy legs. Which is the most likely diagnosis?
Your Answer:
Correct Answer: Varicose eczema
Explanation:Varicose eczema is a common problem, particularly in elderly patients due to stasis or blood pooling from insufficient venous return; the alternative name of varicose eczema comes from a common cause of this being varicose veins. It is often mistaken for cellulitis, but cellulitis is rarely bilateral and is painful rather than itchy.
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This question is part of the following fields:
- Dermatology
- Medicine
-
-
Question 196
Incorrect
-
A 50-year-old male presents to the ER allegedly claiming that he consumed a bottle of antifreeze. Which of the following symptoms is least likely to be associated with this kind of poisoning?
Your Answer:
Correct Answer: Hypertension
Explanation:Loss of vision after consumption of antifreeze is a characteristic presentation of methanol poisoning.
Pathophysiology of methanol toxicity: When ingested, methanol is absorbed rapidly via the gastrointestinal tract in less than 10 minutes. Methanol is not protein-bound and is absorbed directly into the total body water compartment. Metabolism occurs mainly in the liver through serial oxidation via alcohol dehydrogenase and aldehyde dehydrogenase but begins with alcohol dehydrogenase present in the gastric mucosa. Alcohol dehydrogenase oxidizes methanol to formaldehyde, and aldehyde dehydrogenase subsequently oxidizes formaldehyde to formic acid. Formic acid is the primary toxic metabolite that accounts for the associated anion gap metabolic acidosis and end-organ damage.
Clinical presentation: Patients who present within the first 12 to 24 hours following ingestion may appear normal, and this is described as the latent period. Nausea, vomiting, and abdominal pain subsequently ensue, followed by CNS depression and hyperventilation due to metabolic acidosis. Ocular symptoms associated with retinal toxicity are often evident in the form of blurry vision, decreased visual acuity, photophobia, and “halo vision.”
Treatment: Treatment options for methanol toxicity include supportive care, fomepizole (Antizole, 4-Methylpyrazole or 4MP), ethanol, dialysis, and folate.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 197
Incorrect
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Which ion channel does not contribute to the myocardial action potential?
Your Answer:
Correct Answer: Chloride channel
Explanation:The upstroke in the cardiac action potential is due to opening of the sodium channels and an influx of sodium into the cell. The initial repolarization phase is due to transient opening of the potassium channels along with calcium channels. Influx of calcium causes the prolonged plateau phase of the action potential. Delayed opening of the rectifier potassium channel and delayed closure of the calcium channel leads to the repolarization phase of cardiac action potential.
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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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An important hormone controlling the differentiation of monocytes to osteoclasts, by inhibiting the RANKL/ RANK interaction is called?
Your Answer:
Correct Answer: Osteoprotegerin
Explanation:Osteoprotegerin, also known as osteoclastogenesis inhibitory factor (OCIF) is a glycoprotein that acts as a cytokine receptor. It works as a decoy receptor for the receptor activator of nuclear factor-kappaB ligand (RANKL)/osteoclast differentiation factor, thus inhibiting the differentiation of osteoclasts, which are capable of resorbing bone. Osteoprotegerin has been proposed as a therapeutic agent for osteoporosis.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 199
Incorrect
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What is the most important way in which heat is lost from the body?
Your Answer:
Correct Answer: Radiation and conduction
Explanation:The body maintains a constant core temperature by balancing heat loss and heat gain. The mechanisms of heat loss are: radiation, evaporation, convection and conduction. Out of these mechanisms, the most important under normal conditions are radiation, through which body heat is given off to the surrounding atmosphere; and conduction, in which the body releases heat into the objects it comes into contact with.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 200
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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