Medical Physiology Paper I — BMP2104 Paper OmpathStudy

Continued from $1. Medical Physiology II PAPER I Exam Answer Key ### Unit Code: BMP2104 Date: 3rd July, 2018 --- Question 1 Which one of the following does not characterize the micturition reflex? a. Distension of bladder stimulates stretch receptors in bladder wall b. Impulses from stretch receptors signal the micturition center c. Parasympathetic stimulation causes detrusor muscle to contract d. Internal urethral sphincter relaxes under conscious, voluntary control e. None of the above Answer: d) Internal urethral sphincter relaxes under conscious, voluntary control Explanation: The internal urethral sphincter relaxes involuntarily during micturition, not under conscious control. The external urethral sphincter is the one under voluntary control. --- Question 2 The distal convoluted tubule is only permeable to water if present. a. Epinephrine b. Antidiuretic hormone c. Salt d. Human growth hormone e. Adrenaline Answer: b) Antidiuretic hormone Explanation: ADH (vasopressin) makes the distal convoluted tubule and collecting duct permeable to water by inserting aquaporin-2 channels into the membrane. --- Question 3 The kidney secretes for the purpose of stimulating bone marrow activity. a. Renin b. Aldosterone c. Erythropoietin d. Somatomedin e. Calcitriol Answer: c) Erythropoietin Explanation: Erythropoietin is produced by the kidneys in response to hypoxia and stimulates red blood cell production in the bone marrow. --- Question 4 The following factor(s) tend(s) to INCREASE the rate of glomerular filtration (GFR): a. Sympathetic stimulation (norepinephrine) of the afferent arteriole b. Obstruction of the renal tubules, ureter or urethra c. Vasodilation of the efferent arteriole d. None are correct e. All are correct Answer: d) None are correct Explanation: All listed factors decrease GFR. Sympathetic stimulation constricts afferent arterioles, obstruction increases back pressure, and efferent vasodilation reduces filtration pressure. --- Question 5 Concerning the macula densa: a. The macula densa senses the total amount of sodium chloride (sodium chloride concentration times volume) of tubular urine being delivered by the loop of Henle into the distal convoluted tubule b. If the delivery of sodium chloride is lower than normal the macula densa signals the afferent arteriole (pre-glomerular) to release renin c. Renin release causes intravascular angiotensin formation and indirectly aldosterone release d. A and C are correct e. All are correct Answer: e) All are correct Explanation: The macula densa monitors NaCl delivery, triggers renin release when NaCl delivery is low, and renin initiates the renin-angiotensin-aldosterone system. --- Question 6 Concerning angiotensin II: a. The exocrine renin-angiotensin-aldosterone system includes angiotensinogen production by the liver, renin secretion by the juxtaglomerular apparatus and angiotensin-converting enzyme present at the luminal surface of endothelial cells b. Aldosterone, but not AII, stimulate thirst and salt appetite c. Angiotensin II induces marked increases in sodium reabsorption by the loop of henle and the collecting duct d. A and C are correct e. All are correct Answer: d) A and C are correct Explanation: Statement A correctly describes the RAAS system, and C is correct about AII effects on sodium reabsorption. Statement B is false - AII (not aldosterone) stimulates thirst and salt appetite. --- Question 7 Citric acid cycle is part of what metabolic pathway: a. Amphibolic b. Anabolic c. Catabolic d. None of the above e. Proteolytic Answer: a) Amphibolic Explanation: The citric acid cycle is amphibolic because it serves both catabolic (breaking down substrates for energy) and anabolic (providing intermediates for biosynthesis) functions. --- Question 8 Which one of the following statements is true about the proximal tubule: a. The Na+/K+ ATPase drives sodium into the cell from the urine side of the tubule b. Na+/H+ exchange is largely the mechanism by which hydrogen ion secretion occurs c. Bicarbonate reabsorption is independent of carbonic anhydrase activity d. The pH in the lumen of the proximal tubule can reach as low as about 5.0 e. Anti-diuretic hormone exerts effects here Answer: b) Na+/H+ exchange is largely the mechanism by which hydrogen ion secretion occurs Explanation: Na+/H+ exchange is the primary mechanism for hydrogen secretion in the proximal tubule, essential for bicarbonate reabsorption and acid-base balance. --- Question 9 The following factor(s) tend(s) to INCREASE the rate of glomerular filtration (GFR): a. Decreased albumin concentration in plasma b. Vasodilation of the afferent (pre-glomerular) arteriole c. Vasoconstriction of the efferent (post-glomerular) arteriole d. A and C are correct e. All are correct Answer: e) All are correct Explanation: Decreased plasma albumin reduces oncotic pressure, afferent vasodilation increases glomerular pressure, and efferent vasoconstriction increases filtration pressure - all increase GFR.