To maintain the pH and ionic balance of the body fluids, the proximal convoluted tubule selectively secretes all the following into the filtrate except:
| I. | Hydrogen ion | II. | Potassium ion |
| III. | Ammonia | IV. | Bicarbonate ion |
| 1. | 200 ml | 2. | 12 L |
| 3. | 122 L | 4. | 288 L |
| I: | Small amounts of urea is transported back to medullary interstitium by ascending portion of vasa recta |
| II: | NaCl is returned to the medullary interstitium by the descending portion of vasa recta |
| I: | Each kidney of an adult human measures 10-12 cm in length, 5-7 cm in width and 2-3 cm in thickness. |
| II: | The DCTs of many nephrons open into a straight tube called collecting duct. |
| III: | Each nephron has two parts – the glomerulus and the renal tubule. |
| IV: | The renal tubule begins with the proximal convoluted tubule. |
| 1. | Only I and II | 2. | Only I, II and III |
| 3. | Only II and III | 4. | I, II, III and IV |
Potassium ions:
| I: | are filtered at the glomerulus |
| II: | are reabsorbed at the PCT |
| III: | are secreted at DCT |
| 1. | I & II only | 2. | I & III only |
| 3. | II & III only | 4. | I, II & III |
| Animal | Excretory organs | Excretory product | |
| 1. | Labeo (Rohu) | Nephridial tubes | Ammonia |
| 2. | Salamander | Kidney | Urea |
| 3. | Peacock | Kidney | Urea |
| 4. | Housefly | Renal tubules | Uric acid |
| Assertion (A): | An excess of aldosterone can cause a decrease in potassium ion concentration in body fluids. |
| Reason (R): | Aldosterone acts mainly at the renal tubules and stimulates the reabsorption of Na+ and water. |
| 1. | Both (A) and (R) are True but (R) does not correctly explain (A). |
| 2. | (A) is True but (R) is False. |
| 3. | Both (A) and (R) are False. |
| 4. | Both (A) and (R) are True and (R) correctly explains (A). |
| Assertion (A): | Ascending limb of the loop of Henle is impermeable to water and allows transport of electrolytes actively or passively. |
| Reason (R): | Dilution of filtrate takes place due to efflux of electrolytes in the medullary fluid |
| 1. | (A) is True, (R) is False |
| 2. | (A) is False, (R) is True |
| 3. | Both (A) and (R) are True and (R) is the correct explanation of (A) |
| 4. | Both (A) and (R) are True but (R) is not the correct explanation of (A) |
| Assertion (A): | Vasa recta and Henle's loop play a significant role in maintaining high osmolarity of medullary interstitial fluid |
| Reason (R): | Osmolarity increases from 300 mOsmolL-1 to 1200 mOsmolL-1 as we move from cortex to medullary region |
| 1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
| 3. | (A) is True but (R) is False. |
| 4. | Both (A) and (R) are False. |
| Assertion (A): | Na+ reabsorption from glomerular filtrate occurs in PCT, ascending limb of loop of Henle and collecting duct |
| Reason (R): | Na+ is always reabsorbed by passive process in PCT, ascending limb of loop of Henle and collecting duct |
| 1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
| 3. | (A) is True but (R) is False. |
| 4. | Both (A) and (R) are False. |