In the RAAS sequence, which event occurs immediately after angiotensinogen is converted to angiotensin I?

In the RAAS sequence, which event occurs immediately after angiotensinogen is converted to angiotensin I?

• A. Change in posture
• B. Conversion of angiotensinogen to angiotensin I
• C. Formation of active form of angiotensin
• D. Increased reabsorption of water and sodium

Answer: (C)

The essential idea is that the RAAS cascade activates a hormone in a stepwise fashion. After angiotensinogen is cleaved by renin to form angiotensin I, the next step is its conversion to the active hormone, angiotensin II, by angiotensin-converting enzyme (ACE). Angiotensin II is the active form that drives the physiological effects, such as vasoconstriction and stimulation of aldosterone release, which then increases sodium and water reabsorption. So the immediate event is the formation of the active form of angiotensin (angiotensin II). The other options describe downstream effects or unrelated factors and do not occur as the next step in the sequence.