Arrange the events of Renin – Angiotensin mechanism in correct sequence. (A) Activation of JG cell and release of renin. (B) Angiotensin II activates release of aldosterone. (C) Fall in glomerular blood pressure. (D) Reabsorption of Na+ and water from distal convoluted tubule. (E) Angiotensinogen is converted to Angiotensin I and then to Angiotensin II. Choose the correct answer from the options given below :

Solution & Explanation

Answer: (C) (C), (A), (E), (B), (D). Solution: The Renin-Angiotensin (RAAS) cascade is triggered by a fall in glomerular blood pressure (C), which activates the JG cells to release renin (A). Renin converts angiotensinogen to angiotensin I and then angiotensin II (E). Angiotensin II then activates the adrenal cortex to release aldosterone (B), and aldosterone finally causes reabsorption of Na+ and water from the distal parts of the tubule (D). Correct order: C → A → E → B → D. NCERT Reference: Ch 16, p.212, lines 23-32 — "A fall in glomerular blood flow/glomerular blood pressure/GFR can activate the JG cells to release renin which converts angiotensinogen in blood to angiotensin I and further to angiotensin II ... Angiotensin II also activates the adrenal cortex to release Aldosterone. Aldosterone causes reabsorption of Na+ and water from the distal parts of the tubule."