Answer: Renin cleaves angiotensinogen to Ang I, ACE converts to Ang II, Ang II stimulates aldosterone secretion from adrenal cortex.
- A Renin cleaves angiotensinogen to Ang I, ACE converts to Ang II, Ang II stimulates aldosterone secretion from adrenal cortex
- B Renin is converted directly into aldosterone by hepatic liver enzymes without any intermediate steps under most conditions encountered
- C Aldosterone secreted by the adrenal cortex stimulates juxtaglomerular cells to release more renin as frequently observed in practice
- D ACE inhibitors bind angiotensin II receptors directly to amplify overall RAAS signaling activity in many documented cases
Correct answer: A. Renin cleaves angiotensinogen to Ang I, ACE converts to Ang II, Ang II stimulates aldosterone secretion from adrenal cortex
Explanation: RAAS: renin (from JG cells) cleaves angiotensinogen to angiotensin I. ACE (in lungs) converts Ang I to Ang II. Ang II: vasoconstricts + stimulates aldosterone (zona glomerulosa) → Na+/water retention.
Filtrate flows through four functionally distinct stages of the nephron: Bowman's capsule filters blood, the PCT reabsorbs most useful substances unconditionally, the Loop of Henle builds a concentration gradient via counter-current exchange, the DCT secretes selected substances, and the collecting duct performs the final ADH-controlled water reabsorption.
Concept context
Nitrogenous waste, kidney structure, urine formation in the nephron, and hormonal regulation of excretion.
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