Q: Answer it A: These are physiology MCQs True/False for Q1–10, single correct for Q11–20. Here are the answers based on core physiology knowledge: --- Q1–10: True T / False F Q1. Urine concentration depends on: - a. ADH — T - b. Medullary gradient — T - c. Vasa recta — T - d. GFR — F GFR affects volume, not concentration per se - e. Tubular permeability — T Q2. Movements of small intestine are: - a. Segmentation contractions — T - b. Pendular movements — T - c. Mass peristalsis — F this occurs in the large intestine, not small intestine - d. Peristaltic rush — T occurs in extreme situations - e. Movements of villi — T Q3. Acid-base regulation by kidney includes: - a. H⁺ secretion — T - b. HCO₃⁻ reabsorption — T - c. NH₃ formation — T - d. CO₂ excretion — F CO₂ excretion is a lung function - e. Phosphate buffer — T Q4. Clearance of a substance depends on: - a. Filtration — T - b. Reabsorption — T - c. Secretion — T - d. Plasma concentration — T - e. Urine flow rate — F clearance = UV/P; urine flow rate is part of the equation but clearance is independent of flow rate for freely filtered substances — however technically UV/P does involve urine flow; this is borderline T by formula but F conceptually as a determinant Q5. Functions of ADH: - a. Increases water permeability of collecting duct — T - b. Acts on collecting duct — T - c. Decreases urine concentration — F it increases urine concentration - d. Increases urine volume — F it decreases urine volume - e. Inserts aquaporins — T Q6. Juxtaglomerular apparatus consists of: - a. Macula densa — T - b. JG cells — T - c. Mesangial cells — T extraglomerular mesangial/lacis cells - d. Podocytes — F - e. Loop of Henle — F Q7. Factors increasing renin secretion: - a. Low blood pressure — T - b. Low Na⁺ at macula densa — T - c. Sympathetic stimulation — T - d. High blood pressure — F - e. High Na⁺ — F Q8. Effects of aldosterone: - a. Na⁺ reabsorption — T - b. K⁺ secretion — T - c. H⁺ secretion — T - d. Water excretion — F water is retained, not excreted - e. Increased ECF volume — T Q9. Properties of glomerular filtration barrier: - a. Size selective — T - b. Charge selective — T - c. Allows proteins — F proteins are normally excluded - d. Allows water — T - e. Allows glucose — T Q10. Hormones inhibiting gastric motility and emptying: - a. VIP — T - b. GIP — T - c. Gastrin — F gastrin stimulates gastric motility - d. Motilin — F motilin stimulates motility - e. Somatostatin — T --- Q11–20: Single Best Answer Q Answer Reason ------------------- 11. Transport maximum Tm refers to: c. Maximum reabsorption capacity Tm = the maximum rate at which tubules can reabsorb a substance 12. Maximum reabsorption occurs in: b. PCT Proximal Convoluted Tubule 65–70% of filtered load reabsorbed here 13. Widely used clinical test for GFR: b. Creatinine clearance Inulin is the gold standard but creatinine is the clinical standard 14. Mechanism maintaining constant renal blood flow: c. Autoregulation Myogenic reflex + tubuloglomerular feedback 15. Part of nephron responsible for urine dilution: c. Thick ascending limb Impermeable to water; actively transports NaCl — the "diluting segment" 16. Cyanide poisoning causes death due to: c. Destruction of cytochrome oxidase Cyanide inhibits cytochrome c oxidase Complex IV, blocking cellular respiration 17. Surfactant: a. Increase compliance of lung Reduces surface tension → increases compliance 18. Renal threshold for glucose is approximately: b. 180 mg/dL Glucosuria appears when plasma glucose exceeds 180 mg/dL 19. Function of Cholecystokinin CCK: b. Stimulates pancreatic secretion with enzymes CCK stimulates enzyme-rich pancreatic juice and relaxes the sphincter of Oddi so option a is false 20. Usual stimulus of peristalsis: a. Distension Stretch of the gut wall is the primary trigger myenteric reflex
