All Free Physiology MCQs with Answers

• A. 250
• B. 800
• C. 1260
• D. 1500

Explanation: Renal blood flow is approximately 20–25% of cardiac output, giving a typical value near 1,200–1,300 mL/min in an adult.

• A. Na+
• B. HCO3-
• C. CL-
• D. PO4-2

Explanation: In the proximal tubule, NH4⁺ can substitute for H⁺ on the Na⁺/H⁺ exchanger, allowing ammonia-derived acid to be secreted while Na⁺ is…

• A. Creatinine clearance
• B. Renal plasma flow
• C. G.F.R
• D. P.A.H. clearance

Explanation: Inulin is freely filtered by the glomerulus and is neither reabsorbed nor secreted by renal tubules, so its clearance equals the…

• A. Aldosterone
• B. Angiotensin II
• C. Vasopressin
• D. Epinephrine

Explanation: Vasopressin directly increases collecting-duct water permeability, while aldosterone and angiotensin II support sodium and water retention…

• A. Inulin and PAH
• B. Urea and diodrast
• C. PAH and Phenol red
• D. Inulin and mannitol

Explanation: Filtration fraction is calculated as GFR divided by renal plasma flow. Inulin clearance estimates GFR and PAH clearance estimates…

• A. High
• B. Low
• C. Same
• D. Greatly increased

Explanation: Renal glycosuria occurs when glucose appears in urine despite a normal blood glucose level because proximal tubular glucose reabsorption…

• A. Ammonia
• B. Potassium
• C. Bicarbonate
• D. Sodium

Explanation: The proximal tubule has high permeability to sodium and reabsorbs most of the filtered sodium load, mainly through active transport and…

• A. Proximal segment
• B. Distal convoluted tubule
• C. Collecting duct
• D. Loop of Henle

Explanation: The proximal tubule reabsorbs about 65% of the glomerular filtrate, including large amounts of sodium and water.

• A. Plasma oncotic pressure is increased
• B. Glomerular hydrostatic pressure is decreased
• C. Tubular hydrostatic pressure is increased
• D. Increased renal blood flow

Explanation: An increase in renal blood flow can increase glomerular capillary filtration and hence GFR, whereas increased plasma oncotic, tubular…

• A. Two million
• B. One million
• C. Four million
• D. ½ million

Explanation: A normal adult kidney contains approximately one million nephrons, although the number varies between individuals.

• A. 1.5 l/day
• B. 3 l/day
• C. 0.5 l/day
• D. 2 l/day

Explanation: Average adult urine output is about 1 to 2 litres daily, with approximately 1.5 litres per day commonly used as the normal value.

• A. 100%
• B. 0%
• C. 60%
• D. 50%

Explanation: Under normal conditions, essentially 100% of filtered glucose is reabsorbed in the proximal convoluted tubule through sodium-glucose…

• A. More reabsorption in the PCT
• B. All of these
• C. More reabsorption of DCT and collecting ducts
• D. More concentration in loop of Henle

Explanation: Dehydration increases proximal sodium and water reabsorption, strengthens the medullary concentration gradient through the loop of Henle…

• A. PAH
• B. Urea
• C. Inulin
• D. Glucose

Explanation: Inulin is freely filtered and neither reabsorbed nor secreted, so the amount cleared from plasma equals the GFR.

• A. Vasopressin
• B. Erythropoietin
• C. Renin
• D. 1,2,5 Dihydroxy cholecalciferol

Explanation: The kidney produces renin, erythropoietin, and active vitamin D, 1,25-dihydroxycholecalciferol.

• A. Urea
• B. Bicarbonate ion
• C. Chloride
• D. Carbohydrate

Explanation: Carbonic anhydrase catalyses the reversible reaction between carbon dioxide and water, generating carbonic acid and ultimately bicarbonate…

• A. Increase in renal blood flow
• B. Increase in glomerular filtration rate
• C. Decrease in reabsorption of Na Cl
• D. Increase in NaCl concentration in urine

Explanation: In osmotic diuresis, a poorly reabsorbed solute retains water in the tubular fluid and reduces reabsorption of water and accompanying…

• A. Proximal tubule
• B. Descending limb of loop of Henle
• C. Collecting tubule
• D. Ascending limb of loop of Henle

Explanation: The thick ascending limb is effectively impermeable to water while actively reabsorbing NaCl, making it the diluting segment of the…

• A. Distal tubule
• B. Henle's loop
• C. Proximal tubule
• D. Collecting duct

Explanation: Tubular fluid becomes most concentrated as it descends through the water-permeable limb of Henle into the hyperosmotic medulla, reaching…

• A. Proximal tubule
• B. Loop of Henle
• C. Collecting tubule
• D. Vasa recta

Explanation: ADH inserts aquaporin-2 water channels into principal cells of the late distal tubule and collecting ducts, increasing water permeability…