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Question 1
Correct
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In the presence of oxygen , lactate that was produced under anaerobic conditions is converted to:
Your Answer: Pyruvate
Explanation:Lactate can be used in two ways:Oxidation back to pyruvate by well-oxygenated muscle cells, heart cells, and brain cells. Pyruvate is then directly used to fuel the Krebs cycle orConversion to glucose via gluconeogenesis in the liver and release back into circulation.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 2
Correct
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Which of the following structures of the cardiac conduction system is located in the right posterior portion of the interatrial septum?
Your Answer: AV node
Explanation:AV node is located at the right posterior portion of the interatrial septum.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 3
Correct
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Where does protein digestion begin?
Your Answer: Stomach
Explanation:Digestion typically begins in the stomach when pepsinogen is converted to pepsin by the action of hydrochloric acid, and continued by trypsin and chymotrypsin in the small intestine.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 4
Correct
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Concerning protein digestion:
Your Answer: Most protein digestion occurs in the duodenum
Explanation:Human pepsinogens can be divided into two immunochemically distinct groups: Pepsinogen I (PG I) and Pepsinogen II (PGII). PG I is secreted mainly by chief cells in the fundic mucosa whereas PGII is secreted by the pyloric glands and the proximal duodenal mucosa. Maximal acid secretion correlates with PG I. Most protein digestion occurs in the duodenum/jejunum. Pepsin functions best in an acidic environment and specifically at a pH of 1.5 to 3.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 5
Correct
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The energy needed for glycogen synthesis comes from which compound?
Your Answer: UTP
Explanation:Glycogen synthesis is, unlike its breakdown, endergonic—it requires the input of energy. Energy for glycogen synthesis comes from uridine triphosphate (UTP)
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 6
Correct
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Question 7
Correct
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Tunica intima is made up of?
Your Answer: Endothelial cells
Explanation:Tunica intima is a single cell thick lining of endothelial cells that lines the inside of the blood vessels. It is the inner most layer of the blood vessel.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 8
Correct
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Which of the following features do mast cells and basophils have in common:
Your Answer: Are essential for immediate type-hypersensitivity reactions
Explanation:Anaphylaxis is a severe immediate allergic reaction of rapid onset affecting many body systems. It is due to the release of inflammatory mediators and cytokines from mast cells and basophils. Basophils are the least common of the granulocytes, representing about 0.5 to 1% of circulating white blood cells. However, they are the largest type of granulocyte. They are responsible for inflammatory reactions during immune response, as well as in the formation of acute and chronic allergic diseases, including anaphylaxis, asthma, atopic dermatitis and hay fever. They can perform phagocytosis (cell eating), produce histamine and serotonin that induce inflammation, and heparin that prevents blood clotting. Mast cells are similar in appearance and function. Both cell types store histamine, a chemical that is secreted by the cells when stimulated.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 9
Correct
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There is a measure of dispersion of a set of data from its mean. Which of following is the best term which can describe the above?
Your Answer: Standard deviation (root mean square deviation)
Explanation:Standard deviation is defined as the measure of dispersion of a set of data from its mean. It measures the absolute variability of a distribution; the higher the dispersion or variability, the greater is the standard deviation and greater will be the magnitude of the deviation of the value from their mean.
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This question is part of the following fields:
- Medicine
- Research Skills
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Question 10
Correct
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The chromosomes that principally encode for proteins or RNA molecules involved in mitochondrial function are found:
Your Answer: In the nucleus of each diploid cell
Explanation:While mitochondria have their own small circular DNA (mtDNA) that encodes some of the proteins and RNAs required for mitochondrial function, the majority of proteins involved in mitochondrial function are encoded by nuclear DNA. These nuclear genes are transcribed in the nucleus and then translated into proteins in the cytoplasm. The proteins are subsequently imported into the mitochondria.
Therefore, the correct answer is:
- In the nucleus of each diploid cell
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This question is part of the following fields:
- Genetics
- Medicine
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Question 11
Correct
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A 72 year old female, known with rheumatoid arthritis for last 17 years, presents with recurrent attacks of red eyes with a sensation of grittiness. Which of the following is most likely cause of the red eyes?
Your Answer: keratoconjunctivitis sicca
Explanation:Rheumatoid arthritis is an inflammatory systemic disease associated with some extraarticular manifestations. Keratoconjunctivitis sicca, episcleritis, scleritis, corneal changes, and retinal vasculitis are the most common ocular complications among extraarticular manifestations of RA. The overall prevalence of keratoconjunctivitis sicca also known as dry eye syndrome among patients of RA is 21.2% and is the most common with sense of grittiness in the eyes.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 12
Correct
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What is troponin?
Your Answer: A component of thin filaments
Explanation:Skeletal muscle cytoplasmic proteins include myosin and actin (also known as thick and thin filaments, respectively) which are arranged in a repeating unit called a sarcomere. Troponin is a component of thin filaments (along with tropomyosin), and is the protein to which calcium binds.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 13
Correct
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The Afferent neuron that supplies all sensory elements of the muscle spindle is what type of sensory neuron?
Your Answer: Ia
Explanation:Muscle spindle is supplied by both sensory and motor nerves. Sensory supply is Type Ia fibers whereas motor supply is gamma motor neurone.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 14
Correct
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Question 15
Correct
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Which of the following is the smallest cell of the nervous system?
Your Answer: Microglia
Explanation:Microglia are the smallest of the neuroglial cells in the nervous system. They are scattered throughout the central nervous system and have phagocytic properties.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 16
Correct
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Blood flow to the subendocardial portions of the left ventricular muscle occurs mainly during:
Your Answer: Diastole
Explanation:The sub endocardium receives the least amount of blood from the coronary arteries. During systole the coronary arteries collapse as a result of the pressure from contraction that is exerted on them. During diastole the heart muscle relaxes and the pressure on the coronary vessels is relieved allowing blood to flow through them to the sub endocardium.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 17
Correct
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Which of the following is NOT an effect of a positive inotropic agent on the heart?
Your Answer: It decreases the rate of rise in ventricular blood pressure during systole
Explanation:Inotropic agents increase the contractility of the heart as well as the rate of rise in ventricular blood pressure during systole, generating a greater pressure and increasing the stroke volume e.g. like catecholamines do.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 18
Correct
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During exercise, a man consumes 2L O2/min, his arterial 02 content is 190 ml/l and the 02 content of his mixed venous blood is 130ml/l. His cardiac output is approximately:
Your Answer: 33l/min
Explanation:In Fick’s original method, the following variables are measured:VO2, oxygen consumption in ml of pure gaseous oxygen per minute. This may be measured using a spirometer within a closed rebreathing circuit incorporating a CO2 absorberCa, the oxygen concentration of blood taken from the pulmonary vein (representing oxygenated blood)Cv, the oxygen concentration of blood from an intravenous cannula (representing deoxygenated blood)From these values, we know that:VO2 = (CO x Ca) – (CO x Cv)where CO = Cardiac Output, Ca = Oxygen concentration of arterial blood and Cv = Oxygen concentration of mixed venous blood.This allows us to sayCO = VO2/{Ca – Cv}and hence calculate cardiac output.Therefore CO = 2/(0.190-0.130) = 33l/minNote that (Ca – Cv) is also known as the arteriovenous oxygen difference.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 19
Incorrect
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The posterior aspect of the interventricular septum is supplied by:
Your Answer: A branch of the left coronary artery
Correct Answer: A branch of the right coronary artery
Explanation:The posterior aspect of the heart is supplied by the posterior interventricular artery which is a branch of the right coronary artery.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 20
Correct
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Emulsification of dietary lipids is brought about by
Your Answer: Bile salts
Explanation:Digestion of fats can begin in the mouth where lingual lipase breaks down some short chain lipids into diglycerides. However fats are mainly digested in the small intestine. The presence of fat in the small intestine produces hormones that stimulate the release of pancreatic lipase from the pancreas and bile from the liver which helps in the emulsification of fats for absorption of fatty acids.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 21
Correct
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The pressure in the portal circulation is normally adjusted in the:
Your Answer: Sinusoids
Explanation:The pressure in the portal circulation depends on the pressure of the hepatic sinusoids mainly because the direction of transport of nutrients in the portal vein occurs from the portal vein to the hepatic sinusoids.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 22
Correct
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Which of the following cells secrete glucagon?
Your Answer: A cells
Explanation:Glucagon counteracts hypoglycaemia and opposes insulin by promoting gluconeogenesis and glycogenolysis. It also decreases fatty acid synthesis in the liver and adipose tissue, and promotes lipolysis. It is secreted by the pancreatic islet α-cells. Its production is regulated by the insulin produced in β-cells.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 23
Correct
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Regarding integrins, which option is false?
Your Answer: Play no role in cell signalling.
Explanation:Integrins are transmembrane receptors that facilitate cell-extracellular matrix (ECM) adhesion. Upon ligand binding, integrins activate signal transduction pathways that mediate cellular signals such as regulation of the cell cycle, organization of the intracellular cytoskeleton, and movement of new receptors to the cell membrane. Integrins are obligate heterodimers, meaning that they have two subunits: α (alpha) and β (beta). Integrins play an important role in cell signalling by modulating the cell signalling pathways of transmembrane protein kinases such as receptor tyrosine kinases (RTK).
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 24
Correct
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Sequence of events in formation of speech are:
Your Answer: Wernicke’s area---arcuate fasciculus---broca’s area---insula---motor cortex---speech
Explanation:Wernicke’s area is located in the categorical hemisphere or left hemisphere in about 95% of right handed individuals and 60% of left handed individuals. It is involved in the comprehension or understanding of written and spoken language. In contrast Broca’s area is involved in production of language. Firstly, the language is accessed in the Wernicke’s area and these words are sent via the arcuate fasciculus to the Broca’s area, where instructions for articulation is generated. This is then sent from Broca’s are to the motor cortex for the articulation.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 25
Correct
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The parasympathetic innervation of the parotid salivary gland arrives from the salivary nuclei:
Your 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 26
Correct
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The haustral pattern seen in the normal colon is produced by
Your 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
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Question 27
Correct
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A 28 year old female presents to the rheumatology clinic for review. She has a history of adult onset Still's disease and complains of joint pains and persistent skin rash despite undergoing treatment with methotrexate and etanercept. On examination, an erythematous macular rash and active synovitis is noted. CRP is high (95 mg/dl). Which of the following interventions would be most appropriate?
Your Answer: Anakinra
Explanation:Adult onset Still’s disease (AOSD) is an uncommon systemic inflammatory disease on the clinical spectrum of autoinflammatory disorders. Its presentation and clinical course may result in several well-differentiated phenotypes: from a systemic and highly symptomatic pattern to a chronic articular pattern. Overproduction of numerous pro-inflammatory cytokines is observed in AOSD. Anakinra, a human interleukin (IL)-1R antagonist, has recently been approved in the treatment of AOSD. Denosumab is a RANK ligand inhibitor used in the treatment of osteoporosis. Mepolizumab is used in the treatment of severe asthma with elevated eosinophils. There is some evidence to support the use of tocilizumab, an anti-IL6 monoclonal antibody in adult onset Still’s, but there is stronger data favouring the use of tocilizumab in the treatment of rheumatoid arthritis. Rituximab is usually reserved for patients who are unresponsive to anakinra.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 28
Correct
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Which of the following with regard to DNA mutations does not fit:
Your Answer: All gene mutations cause clinical disease entities
Explanation:All gene mutations do not cause a clinical manifestation of the disease, some gene mutations are silent mutations. They are present but do not cause any disease.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 29
Correct
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Myocardium requires more oxygen to expel blood in:
Your Answer: A stenotic aortic valve
Explanation:In aortic valve stenosis, increased ventricular pressure Is needed to expel the blood into the aorta. Increased pressure means increased contractility hence increase O2 consumption by the heart muscles.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 30
Correct
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A 30-year-old male with a history of premature cardiovascular disease in the family has come for review of his lab investigations. His fasting cholesterol is 8.4 mmol/l with high-density lipoprotein (HDL) of 1.6 mmol/l. You elect to commence him on atorvastatin 20 mg PO daily.Which of the following best describes the mechanism of action of the statins?
Your Answer: They inhibit HMG CoA reductase
Explanation:Statins are a selective, competitive inhibitor of hydroxymethylglutaryl-CoA (HMG-CoA) reductase, which is the enzyme responsible for the conversion of HMG-CoA to mevalonate in the cholesterol synthesis pathway.Statins are usually well tolerated with myopathy, rhabdomyolysis, hepatotoxicity, and diabetes mellitus being the most common adverse reactions. This is the rate-limiting step in cholesterol synthesis, that leads to increased hepatic low-density lipoprotein (LDL) receptors and reduced hepatic VLDL synthesis coupled with increased very-low-density lipoprotein (VLDL) clearance.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 31
Correct
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Neutrophils are key components of the innate immune system. They contain numerous primary and secondary granules involved in killing and digesting microorganisms. With regard to defensins, they are:
Your Answer: Naturally occurring cysteine-rich antibacterial and antifungal polypeptides
Explanation:Cationic antimicrobial peptides, including defensins, cathelicidins, and thrombocidins, provide important initial defences against invading microbes. These peptides bind the bacterial membrane and form pores, killing the bacterium by hypo-osmotic lysis.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 32
Correct
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Which of the following best describe N. Meningitides?
Your Answer: Gram negative cocci
Explanation:Neisseria meningitidis, often referred to as meningococcus, is a gram negative bacterium that can cause meningitis and other forms of meningococcal disease such as meningococcaemia, a life-threatening sepsis. The bacterium is referred to as a coccus because it is round, and more specifically, diplococcus because of its tendency to form pairs. About 10% of adults are carriers of the bacteria in their nasopharynx.
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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Question 33
Correct
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Salty taste is triggered by:
Your Answer: Amiloride-sensitive sodium channel
Explanation:Amiloride-sensitive sodium channels also known as epithelial Na channels is a membrane bound ion channel that is selectively permeable to Na+ ions. These channels are located throughout different epithelial membranes in the body. It is found in taste receptor cells, where it plays an important role in salt taste perception. They are also located in the kidney, the lung and the colon. Hyperpolarization-activated, cyclic nucleotide-gated (HCN) voltage-gated ion channels are widely seen in the cortex, hippocampus, thalamus and brain regions that underlie the generation of both focal and generalized-onset seizures. The metabotropic glutamate receptor (mGluRs) perform a variety of functions in the central and peripheral nervous systems. They are involved in learning, memory, anxiety, and the perception of pain. Gustducin is a G protein associated with taste and gustatory system. It plays a major role in sensation of bitter, sweet and umami stimuli.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 34
Correct
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The ATPase of parietal cells moves:
Your 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
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Question 35
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 36
Correct
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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: 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 37
Correct
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Which of the following is a product of D cells
Your Answer: Somatostatin
Explanation:Somatostatin is secreted by D cells, HCL and intrinsic factor secreted by parietal cells. Trefoil peptides are secreted by mucus secreting goblet cells and gastrin releasing peptide (grp) by post-ganglionic fibers of the vagus nerve (which innervate the G cells of the stomach).
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 38
Correct
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Glucose absorption in the small intestine is coupled with which of the following electrolytes?
Your Answer: Na
Explanation:Sodium-glucose linked transporter are family of proteins of different types. SGLT1 transporter is found in the intestinal mucosa of the small intestine and absorbs glucose via cotransport of Na+ ions.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 39
Correct
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Question 40
Correct
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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: 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 41
Correct
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Question 42
Correct
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Question 43
Correct
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A 62 year old female complains of pain and stiffness in her shoulders. She also finds it difficult to get out of her chair. From the list of symptoms below, choose the one most likely to support the diagnosis of polymyalgia rheumatica.
Your Answer: Low grade fever
Explanation:Polymyalgia rheumatica is an inflammatory disease which usually causes stiffness and pain in the shoulder – this can also occur in the pelvic girdle muscles. Its onset can either be subacute or acute and is associated with a systemic inflammatory response. This, therefore, causes symptoms such as fever, weight loss, anorexia, and malaise. Polymyalgia rheumatica is unpredictable in its course and it is known that 30 per cent of patients also present with giant cell arteritis. The cause of this disease is unknown but studies have shown it have infectious origins. Diagnosis of polymyalgia rheumatica can be difficult and other inflammatory diseases have to be excluded first. Patients with this disease are usually over 60 years of age (it is very rarely seen in those under 50). Muscle weakness does not present, although this can be hard to assess when the patient is in pain. Low-grade fever and weight loss are typical of this disease due to chronic inflammation. As such, weight gain is very rare and peripheral joints are usually not affected (they can be affected but it is very rare). Also, muscle tenderness is not a specific symptom of the disease – it is therefore not a classical finding of polymyalgia rheumatica. Although patients usually complain of stiffness and pain, the muscles are usually not significantly tender – this is usually more associated with fibromyalgia or myositis. When investigated, a normochromic/normocytic anaemia; a raised erythrocyte sedimentation rate often over 50 mm/hr., and raised C reactive protein are usually revealed. Symptoms of giant cell arteritis should also be sought, such as headaches, visual disturbances, TIAs (transient ischemic attacks), jaw claudication, and thickened temporal arteries. The patient response to a moderate dose of steroids is useful when confirming a diagnosis of polymyalgia rheumatica. The maximum dose of prednisolone should not exceed 20mg once a day. After treatment, patients should show a 70 per cent improvement in symptoms within a month (between 3-4 weeks). Inflammatory markers should also fall back to their normal levels. Non-steroidal anti-inflammatories are of little use and are associated with morbidity. There is also little evidence for the use of steroidal-sparing agents.
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This question is part of the following fields:
- Geriatrics
- Medicine
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Question 44
Correct
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Select a factor which stimulates glucagon secretion.
Your Answer: Protein meal
Explanation:Several studies have shown that glucagon levels are increased in individuals with a high protein diet. It is still debated, however, whether this type of diet affects insulin levels as well.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 45
Correct
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Which one of the following is able to move across cell membranes by passive diffusion?
Your Answer: CO2
Explanation:The cell membrane is permeable to water molecules and a few other small, uncharged, molecules like oxygen (O2) and carbon dioxide (CO2). Larger molecules like glucose or charged ions are unable to cross passively.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 46
Correct
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What is the effect of vasopressin on the kidney?
Your Answer: Increase collecting duct permeability to water
Explanation:Vasopressin, also known as antidiuretic hormone or ADH, which increases water reabsorption in the kidney’s collecting ducts. It works by increasing water permeability in the collecting ducts and distal convoluted tubules. It induces the exocytosis of AQP-CD-laden vesicles, transferring water channels from intracellular vesicles to the apical plasma membrane, therefore allowing more water to be reabsorbed from the urine in the collecting ducts to the blood.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 47
Correct
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When during the cell cycle does DNA replication occur?
Your Answer: S phase
Explanation:The S phase is known as the synthesis phase. During this phase DNA will begin to replicated, as well as the synthesis of the centrosomes and associated proteins.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 48
Correct
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Selectins
Your Answer: Interact with carbohydrate ligands or mucin complexes on leucocytes and endothelial cells
Explanation:Selectins are involved in constitutive lymphocyte homing, and in chronic and acute inflammation processes, including post-ischemic inflammation. Each selectin has a carbohydrate recognition domain that mediates binding to specific glycans on apposing cells.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 49
Correct
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Which of the following takes place during fasting
Your Answer: Migrating motor complex
Explanation:Migrating motor complexes (MMC) are waves of electrical activity that sweep through the intestines in a regular cycle during fasting. These motor complexes trigger peristaltic waves, which facilitate transportation of indigestible substances such as bone, fiber, and foreign bodies from the stomach, through the small intestine, past the ileocecal sphincter, and into the colon.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 50
Correct
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A 70-year-old male with advanced COPD currently on treatment with salbutamol (as required) presents for review. After a complete history and examination, you conclude that he requires to be stepped up in his inhalational therapy. The decision to add tiotropium bromide to his regime was taken. Which of the following best describe the mechanism of action of tiotropium?
Your Answer: It is a long-acting anticholinergic agent
Explanation:Tiotropium is a specific long-acting antimuscarinic agent indicated as maintenance therapy for patients with COPD (chronic obstructive pulmonary disease). It should be used cautiously in patients with narrow-angle glaucoma, prostatic hyperplasia or bladder neck obstruction.The most frequently encountered adverse effects of tiotropium include pharyngitis, bronchitis, sinusitis, dry mouth, cough, and headaches. Paradoxical bronchospasm may also occur as a rare side-effect. Dry mouth occurs in up to 14% of patients taking tiotropium, in keeping with its anticholinergic profile. Rarer side-effects include tachycardia, blurred vision, urinary retention, and constipation.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 51
Correct
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One of the functions of the spleen with regards to red blood cells is:
Your 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 52
Correct
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Bone marrow barrier is important to:
Your Answer: Allow mature red blood cells to pass into circulation
Explanation:The blood vessels of the bone marrow constitute a barrier, inhibiting immature blood cells from leaving the marrow. Only mature blood cells contain the membrane proteins, such as aquaporin and glycophorin, that are required to attach to and pass the blood vessel endothelium.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 53
Correct
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Which of the following substances is involved in the respiratory burst by the neutrophil?
Your 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 54
Correct
-
Which of the following hormones cause negative feedback on the CRH/ACTH axis?
Your 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
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Question 55
Correct
-
Xanthines (for example Caffeine), exhibit their positive inotropic effect by:
Your Answer: Inhibiting the breakdown cAMP
Explanation:Xanthines exert their positive inotropic effect by inhibiting the breakdown of the cAMP resulting in stronger and sustained contraction.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 56
Correct
-
Of the daily production of CSF, the vast majority is produced in the:
Your Answer: Choroid plexus
Explanation:About 80% of CSF is produced by the choroid plexus. It is also produced by a single layer of column shaped ependymal cells.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 57
Correct
-
Which of the following conditions is procoagulant?
Your Answer: Factor V Leiden
Explanation:Factor V Leiden is a genetic mutation of one of the clotting factors in the blood, Factor V. This mutation makes Factor V resistant to inactivation by activated Protein C, which normally helps to regulate clot formation. As a result, individuals with Factor V Leiden are at increased risk of developing abnormal blood clots (thrombophilia), making it a procoagulant condition.
The other conditions listed are associated with bleeding tendencies rather than increased clotting:
- Afibrinogenemia: A rare genetic disorder where there is a complete lack of fibrinogen, leading to bleeding problems.
- Hemophilia: A group of inherited bleeding disorders where blood does not clot properly due to the lack of sufficient blood-clotting proteins (factors VIII or IX).
- Hypothrombinemia: A condition characterized by low levels of prothrombin, leading to increased bleeding.
- Christmas disease (Hemophilia B): A form of hemophilia caused by a deficiency of factor IX, resulting in a bleeding tendency.
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This question is part of the following fields:
- Haematology
- Medicine
-
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Question 58
Correct
-
Which of the following has the shortest duration:
Your Answer: Atrial systole
Explanation:Atrial systole: 0.1s
Atrial diastole: around 0.4s
Ventricular diastole: 0.4-0.53s
Ventricular systole: 0.27s
PR interval: 0.12-0.2 s
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 59
Correct
-
Which of the flowing plasma proteins has the greatest affinity for T4?
Your Answer: Thyroxin-binding globulin
Explanation:There are three principal plasma thyroid hormone-binding proteins, thyroxine-binding globulin (TBG), transthyretin (TTR), and albumin. TBG is synthesized in the liver and due to its relatively high affinity for iodothyronines, binds and carries approximately 70–75% of circulating T4 and T3.
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This question is part of the following fields:
- Endocrinology
- Medicine
-
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Question 60
Correct
-
Consanguinity shows a strong association with which pattern of inheritance?
Your Answer: Autosomal recessive
Explanation:Consanguinity involves being from the same kinship as another person. It is a common feature of an autosomal recessive mode of inheritance
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This question is part of the following fields:
- Genetics
- Medicine
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Question 61
Incorrect
-
A 42 year old female with a history of SLE presents with an exacerbation of wrist pain. Which of the following markers would be the most suitable for monitoring disease activity?
Your Answer: Anti-Sm titres
Correct Answer: Anti-dsDNA titres
Explanation:A high level of anti-dsDNA in the blood is strongly associated with lupus and is often significantly increased during or just prior to a flare-up. When the anti-dsDNA is positive and the person tested has other clinical signs and symptoms associated with lupus, it means that the person tested likely has lupus. This is especially true if an anti-Sm test is also positive.In the evaluation of someone with lupus nephritis, a high level (titre) of anti-dsDNA is generally associated with ongoing inflammation and damage to the kidneys.A very low level of anti-dsDNA is considered negative but does not exclude a diagnosis of lupus. Only about 65-85% of those with lupus will have anti-dsDNA.Low to moderate levels of the autoantibody may be seen with other autoimmune disorders, such as Sjögren syndrome and mixed connective tissue disease (MCTD).
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 62
Correct
-
Concerning S3, which of the following statements is INCORRECT?
Your Answer: Coincide with atrial contraction
Explanation:A third heart sound also called a ventricular gallop occurs at the beginning of diastole after S2 and is lower in pitch than S1 or S2 as it is not of valvular origin. The third heart sound is benign in youth, some trained athletes, and sometimes in pregnancy but if it re-emerges later in life it may signal cardiac problems, such as a failing left ventricle as in dilated congestive heart failure (CHF). S3 is thought to be caused by the oscillation of blood back and forth between the walls of the ventricles initiated by blood rushing in from the atria. The reason the third heart sound does not occur until the middle third of diastole is probably that during the early part of diastole, the ventricles are not filled sufficiently to create enough tension for reverberation. It may also be a result of tensing of the chordae tendineae during rapid filling and expansion of the ventricle. In other words, an S3 heart sound indicates increased volume of blood within the ventricle. An S3 heart sound is best heard with the bell-side of the stethoscope (used for lower frequency sounds). A left-sided S3 is best heard in the left lateral decubitus position and at the apex of the heart, which is normally located in the 5th left intercostal space at the midclavicular line. A right-sided S3 is best heard at the lower-left sternal border. The way to distinguish between a left and right-sided S3 is to observe whether it increases in intensity with inhalation or exhalation. A right-sided S3 will increase on inhalation, while a left-sided S3 will increase on exhalation.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 63
Correct
-
A 20 year old male student presents to the clinic with swelling of his face, hands and feet along with diffuse abdominal pain. He has a history of similar recurrent episodes since he was 10 years old, with each episode lasting 2-3 days. Examination reveals swelling on face, hands, feet but no sign of urticaria. Family history is significant for similar episodes in the mother who experienced these since childhood, and a brother who passed away following respiratory distress at age of 8 during one such episode. Which of the following tests would be the most helpful in reaching the diagnosis?
Your Answer: C1 esterase inhibitor
Explanation:Hereditary C1 inhibitor deficiency leads to recurrent angioedema without urticaria or pruritus. Physical triggers include dental work, surgery or intubation. Medical triggers include angiotensin-converting enzyme (ACE) inhibitor, tamoxifen, oestrogen-containing medications (e.g., hormone replacement therapy and oral contraceptives). It is diagnosed on the basis of low levels of C1 esterase inhibitor or elevated levels of dysfunctional C1 esterase inhibitor. C4 levels are low between attacks. IgE levels, eosinophils, skin prick tests and RASTs are helpful in other allergic conditions and asthma but not of use in this case.
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This question is part of the following fields:
- Connective Tissue
- Medicine
-
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Question 64
Correct
-
In RFLP (restriction fragment length polymorphism), the DNA fragments are separated by length through a process known as:
Your Answer: Agarose gel electrophoresis
Explanation:Samples of DNA from individuals are broken into pieces by restriction enzymes and the fragments are separated according to their lengths via gel electrophoresis. Although now largely obsolete due to the rise of inexpensive DNA sequencing technologies, RFLP analysis was the first DNA profiling technique inexpensive enough to see widespread application.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 65
Correct
-
Which of the following corresponds to an oblique line drawn from the sternal end of the left 3rd costal cartilage to the sternal end of the right 6th costal cartilage?
Your Answer: Atrio-ventricular (coronary) groove
Explanation:The AV groove corresponds to the right border of the heart. The right border corresponds to a line drawn from the 3rd right costal cartilage to the 6th right costal cartilage; this border is slightly convex to the right.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 66
Correct
-
High titre of which of the following antibodies is not considered diagnostic for the mentioned disease?
Your Answer: Rheumatoid factor in rheumatoid arthritis (RA)
Explanation:Diagnosis of RA is mainly based on clinical features (e.g., morning stiffness, symmetrical joint swelling) and laboratory tests (e.g., anti-CCP). Rheumatoid factor is not very specific for this disease and hence has low reliability. X-ray findings (e.g., soft tissue swelling or joint space narrowing) occur late in the disease and are therefore not typically used for diagnosis.
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This question is part of the following fields:
- Connective Tissue
- Medicine
-
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Question 67
Correct
-
The interventricular septum is supplied anteriorly by the?
Your Answer: Left anterior descending artery
Explanation:The anterior interventricular artery or left anterior descending artery supplies the anterior 2/3rds of the interventricular septum.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 68
Correct
-
Which of the following with regard to autosomal dominant disorders are true:
Your Answer: The offspring of a heterozygous individual has a 50% chance of inheriting the chromosome carrying the disease allele
Explanation:50% of the children will be effected from parents who are heterozygous for an autosomal dominant disorder. An allele can be dominant or recessive. Individuals, meanwhile, can be homozygous or heterozygous: individuals who are homozygous for a certain gene carry two copies of the same allele. individuals who are heterozygous for a certain gene carry two different alleles.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 69
Correct
-
The process in which tissue thromboplastin activates factor VII is best known as:
Your Answer: The extrinsic pathway
Explanation:In the tissue factor pathway (extrinsic), following damage to the blood vessel, FVII leaves the circulation and comes into contact with tissue factor (TF) expressed on tissue-factor-bearing cells (stromal fibroblasts and leukocytes), forming an activated complex (TF-FVIIa).
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This question is part of the following fields:
- Haematology
- Medicine
-
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Question 70
Correct
-
The haemostatic plug formation in response to injured blood vessel wall is stimulated by exposure of which substance to platelets?
Your Answer: Collagen
Explanation:When the endothelium is damaged, the normally isolated, underlying collagen is exposed to circulating platelets, which bind directly to collagen with collagen-specific glycoprotein Ia/IIa surface receptors. This adhesion is strengthened further by von Willebrand factor (vWF), which is released from the endothelium and from platelets.
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This question is part of the following fields:
- Haematology
- Medicine
-
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Question 71
Correct
-
Regarding taste threshold and intensity discrimination:
Your Answer: 30% change in concentration of substance tasted is necessary before an intensity difference can be detected
Explanation:The ability of humans to differentiate differences in intensity of taste is poor. A 30% change in the concentration of the substance being tasted is required before an intensity difference is perceived.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 72
Correct
-
Regarding oxidative deamination of amino acids, which of the following is true?
Your Answer: Occurs in the kidney & liver
Explanation:Oxidative deamination is a form of deamination that generates α-keto acids and other oxidized products from amine-containing compounds, and occurs largely in the liver and kidney. Oxidative deamination is an important step in the catabolism of amino acids, generating a more metabolizable form of the amino acid, and also generating ammonia as a toxic by-product. The addition of ubiquitin to a substrate protein is called ubiquitination.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 73
Correct
-
A patient with a VIPoma (VIP secreting tumour) is likely to exhibit which of the following?
Your Answer: Severe diarrhoea
Explanation:Vasoactive inhibitory peptide (VIP) is found in the nerves innervating the GIT. It markedly stimulates the secretion of intestinal electrolytes and also with them water. This results in secretary diarrhoea. Along with that it also relaxes intestinal smooth muscle including the sphincters, it also results in dilation of the peripheral blood vessels and along with this its also inhibits gastric acid secretions. A VIPoma will exaggerate all this.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
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Question 74
Correct
-
Question 75
Correct
-
The following determines the strength of contraction
Your Answer: Plateau phase
Explanation:The plateau phase which follows is unique to myocytes and results from a small, but sustained inward calcium current through L-type calcium channels lasting 200-400 ms. This calcium influx is caused by a combined increase in permeability of the cell and especially the sarcolemmal membranes to calcium. This plateau (or refractory) phase in myocyte action potential prevents early reactivation of the myocytes and directly determines the strength of contraction
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 76
Correct
-
Question 77
Correct
-
Neurogenesis occurs throughout life in the following two areas:
Your 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 78
Correct
-
Which of the following values of bone mineral density measured by DEXA would signify osteopenia?
Your Answer: T score of -2.2
Explanation:DEXA T Scores:Normal T-score ≥ −1.0Osteopenia −2.5 < T-score < −1.0Osteoporosis T-score ≤ −2.5Severe osteoporosis T-score ≤ −2.5 with fragility fracture
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This question is part of the following fields:
- Endocrinology
- Medicine
-
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Question 79
Correct
-
Which statement is incorrect regarding nociceptor C fibers…
Your Answer: They are thinly myelinated
Explanation:Group C nerve fibers are unmyelinated and have a small diameter, which means they conduct impulses at a low velocity. They carry sensory information and nociception.
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This question is part of the following fields:
- Medicine
- Neurology
-
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Question 80
Correct
-
Which of the following drugs requires plasma level monitoring?
Your Answer: Vancomycin
Explanation:All patients require plasma-vancomycin measurement (after 3 or 4 doses if renal function normal, earlier if renal impairment). There is a risk of nephrotoxicity including renal failure, interstitial nephritis and ototoxicity.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 81
Correct
-
Question 82
Correct
-
Which of the following is true with regard to the acini?
Your 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
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Question 83
Correct
-
A 55 year old cardiac patient is comfortable at rest but heavy housework results in fatigue, palpitations or dyspnoea. What New York Heart Association class best describes the severity of their disease?
Your Answer: NYHA Class II
Explanation:New York Heart Association functional classification:
Class I: no limitation is experienced in any activities; there are no symptoms from ordinary activities.
Class II: slight, mild limitation of activity; the patient is comfortable at rest or with mild exertion.
Class III: marked limitation of any activity; the patient is comfortable only at rest.
Class IV: any physical activity brings on discomfort and symptoms occur at rest.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 84
Correct
-
A 56 year old woman taking procainamide develops drug induced erythematosus. Which of the following features is the most characteristic of this condition?
Your Answer: It may occur with chlorpromazine
Explanation:Drug induced lupus is usually positive for antinuclear and antihistone antibodies, typically without renal or neurologic involvement. However, pulmonary involvement is common. Drugs that can induce lupus include isoniazid, hydralazine, procainamide, chlorpromazine, and other anticonvulsants.
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This question is part of the following fields:
- Connective Tissue
- Medicine
-
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Question 85
Correct
-
Which one of the following will increase an individual’s appetite?
Your Answer: Ghrelin
Explanation:Ghrelin is a hormone which exerts a strong influence on hunger and energy balance. It helps regulate appetite by being secreted when the stomach is empty, to stimulate hunger. When the stomach is filled, its secretion stops.
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This question is part of the following fields:
- Endocrinology
- Medicine
-
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Question 86
Correct
-
Troponin I is inhibited by calcium binding to:
Your Answer: Troponin c
Explanation:At rest troponin I is bound to actin and tropomyosin and covers the site where the myosin head interacts with actin. When calcium enters into the muscle, it binds with troponin C and cause a structural change in troponin I which moves out of the myosin binding site and causes the cross bridges between the actin and myosin filaments to occur.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 87
Correct
-
In most somatic cells telomeres progressively shorten as:
Your 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 88
Correct
-
The following is true about the carotid arterial supply to the brain:
Your Answer: Following carotid occlusion, precapillary anastomoses are unable to prevent infarction
Explanation:The brain has two sources of blood supply; the internal carotid arteries which are the anterior segment or the main artery that supplies the anterior portion of the brain, and the vertebral arteries which is the posterior segment which supplies the posterior portion of the brain. The internal carotid arteries branch and form two major arteries anterior and middle cerebral arteries. The right and left vertebral arteries fuse together at the level of the pons on the anterior surface of the brainstem to form the midline basilar artery. The basilar artery joins the blood supply from the internal carotids in an arterial ring at the base of the brain called the circle of Willis. The anterior and posterior communicating arteries conjoin the two major sources of cerebral vascular supply via the circle of Willis improving the chances of any region of the brain continuing to receive blood if one of the major arteries becomes occluded.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 89
Correct
-
Why is the sub-endocardial portion of the left ventricle the most common site for ischaemic damage and myocardial infarction?
Your Answer: No blood flow occurs during systole
Explanation:The subendocardium receives the least amount of blood from the coronary arteries. During systole the coronary arteries collapse as a result of the pressure due to contraction that is exerted on them. During diastole the heart muscle relaxes and the pressure on the coronary vessels is relieved allowing blood to flow through them to the subendocardium.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 90
Correct
-
The growth promoting protein anabolic effects of insulin are mediated by:
Your Answer: Phosphatidylinositol 3-kinase
Explanation:Phosphatidylinositol 3-kinase or PI-3Ks are a group of enzymes which are involved in a number of different cellular functions. PI-3Ks interact with insulin and the insulin receptor substrate, regulating glucose uptake. They are an important element in the insulin signalling pathway.
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This question is part of the following fields:
- Endocrinology
- Medicine
-
-
Question 91
Correct
-
In the life cycle of plasmodium species:
Your Answer: Merozoites are released from the liver and enter the red blood cell
Explanation:Plasmodium is a genus of parasitic protozoa, many of which cause malaria in their hosts. The parasite always has two hosts in its life cycle: a Dipteran insect host and a vertebrate host. Sexual reproduction always occurs in the insect, making it the definitive host.The life-cycles of Plasmodium species involve several different stages both in the insect and the vertebrate host. These stages include sporozoites, which are injected by the insect vector into the vertebrate host’s blood. Sporozoites infect the host liver, giving rise to merozoites and (in some species) hypnozoites. These move into the blood where they infect red blood cells. In the red blood cells, the parasites can either form more merozoites to infect more red blood cells, or produce gametocytes which are taken up by insects which feed on the vertebrate host. In the insect host, gametocytes merge to sexually reproduce. After sexual reproduction, parasites grow into new sporozoites, which move to the insect’s salivary glands, from which they can infect a vertebrate host bitten by the insect.
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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Question 92
Correct
-
G cells release which of the following substances
Your Answer: Gastrin
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 93
Correct
-
A patient who has recently been diagnosed with SLE undergoes serum testing. A rise in which of the following antibodies would indicate severe systemic involvement?
Your Answer: Anti double-stranded DNA antibodies
Explanation:Anti ds-DNA antibodies are very specific for SLE and their presence most often indicates systemic spread of the disease. These antibodies are present in about 30 percent of the total cases of SLE.
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This question is part of the following fields:
- Connective Tissue
- Medicine
-
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Question 94
Correct
-
In increasing order of concentration, the main anions in plasma are:
Your Answer: Proteins-, HCO3-, Cl-,
Explanation:Anions are negatively charged ions and include: chloride Cl-, bicarbonate HCO3-, sulphate SO4-2, phosphate HPO4-2, and protein anions. Chloride it the most abundant anion followed by bicarbonate and then protein anions.
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This question is part of the following fields:
- Medicine
- Renal
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Question 95
Correct
-
What type of intercellular connection found between cardiac muscle fibers allow for the spread of excitation from one cell to another?
Your Answer: Gap junctions
Explanation:The cardiac muscles have gap junctions in-between the cells. They form 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 96
Correct
-
A 31 year old female with systemic lupus erythematosus wants to know if she has any predisposing factors for the disease. Which of the following carries the greatest risk of developing SLE?
Your Answer: Monozygotic twin
Explanation:An overall concordance rate in monozygotic twins was documented to be 25% as compared to dizygotic twins with 3%. First degree relatives have a chance of around 3% of developing the disease. Caucasians show an increase frequency of HLA-B8. The Japanese lupus patients had a stronger association with HLA-DR2.
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This question is part of the following fields:
- Connective Tissue
- Medicine
-
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Question 97
Correct
-
Regarding glomus cells, which of the following is true?
Your Answer: Contain catecholamines
Explanation:The carotid body detects changes in the composition of arterial blood flowing through it, mainly the partial pressure of oxygen, but also of carbon dioxide. Furthermore, it is also sensitive to changes in pH and temperature.The carotid body is made up of two types of cells, called glomus cells: Glomus type I/chief cells release a variety of neurotransmitters, including acetylcholine, ATP, and dopamine that trigger EPSPs in synapsed neurons leading to the respiratory centre.Glomus type II/sustentacular cells resemble glia, express the glial marker S100 and act as supporting cells.
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This question is part of the following fields:
- Medicine
- Respiratory
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Question 98
Correct
-
The parasympathetic function of the facial nerve is:
Your Answer: Secretion of tears from lacrimal glands, secretion of saliva from the sublingual and submandibular salivary glands.
Explanation:Facial nerve (Cranial Nerve VII) has both sensory and motor components so it is a mixed nerve. It carries axons of:General somatic afferent – to skin and the posterior earGeneral visceral efferent – which innervate sublingual, submandibular and lacrimal glands and the mucosa of the nasal cavity.General visceral afferent – provide sensation to soft palate and parts of the nasal cavity.Special visceral efferent – innervate muscles of facial expression and stapedius, the posterior belly of the digastric and the stylohyoid musclesSpecial visceral afferent – provide taste to the anterior two-thirds of the tongue via chorda tympani.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 99
Correct
-
The nucleus tractus solitaries is medullary nucleus that processes the following inputs except:
Your Answer: Sensory input from the semi-circular canal (CN VIII)
Explanation:Located in the brain stem is a series of purely sensory nuclei known as tractus solitaries. Inputs of the nucleus tractus solitaries include:Taste information from the facial nerve (anterior 2/3 of the tongue), glossopharyngeal nerve (posterior 1/3) and vagus nerve (small area on the epiglottis).Sensory information from the ear (auricular branch of the vagus nerve).Chemoreceptors and mechanoreceptors of the general visceral afferent pathway (GVA) in the carotid body via glossopharyngeal nerve, aortic bodies, and the sinoatrial node, via the vagus nerve.Chemically and mechanically sensitive neurons of the general visceral afferent pathway (GVA) with endings located in the heart, lungs, airways, gastrointestinal system, pharynx, and liver via the glossopharyngeal and vagus nerves.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 100
Correct
-
Role of bile salts in digestion of fats include
Your Answer: Reduce surface tension, emulsification and transportation
Explanation:Bile acts to some extent as a surfactant reducing surface tension, helping to emulsify the lipids in food. Bile salt anions are hydrophilic on one side and hydrophobic on the other side; consequently, they tend to aggregate around droplets of lipids (triglycerides and phospholipids) to form micelles, with the hydrophobic sides towards the fat and hydrophilic sides facing outwards. The hydrophilic sides are negatively charged, and this charge prevents fat droplets coated with bile from re-aggregating into larger fat particles.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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SESSION STATS - PERFORMANCE PER SPECIALTY
