Angiotensin II causes all of the following except
**Core Concept**
Angiotensin II is a potent vasoconstrictor and a key component of the renin-angiotensin-aldosterone system (RAAS). It plays a crucial role in regulating blood pressure, fluid balance, and electrolyte homeostasis by stimulating the release of aldosterone from the adrenal cortex and promoting vasoconstriction through its effects on blood vessels.
**Why the Correct Answer is Right**
Angiotensin II stimulates the release of aldosterone from the adrenal cortex, leading to increased sodium reabsorption in the collecting ducts of the kidneys and subsequent water retention. This results in increased blood volume and blood pressure. Additionally, angiotensin II promotes vasoconstriction by stimulating the contraction of vascular smooth muscle cells, which increases peripheral resistance and blood pressure. Furthermore, angiotensin II stimulates the release of antidiuretic hormone (ADH) from the posterior pituitary gland, promoting water reabsorption in the collecting ducts and further increasing blood volume and blood pressure.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it is a known effect of angiotensin II. Angiotensin II does indeed stimulate the release of aldosterone, which leads to increased sodium reabsorption and water retention.
**Option B:** This option is incorrect because it is a known effect of angiotensin II. Angiotensin II does indeed promote vasoconstriction, which increases peripheral resistance and blood pressure.
**Option C:** This option is incorrect because it is a known effect of angiotensin II. Angiotensin II does indeed stimulate the release of ADH, which promotes water reabsorption and increases blood volume and blood pressure.
**Clinical Pearl / High-Yield Fact**
It is essential to remember that the RAAS system plays a crucial role in regulating blood pressure and fluid balance. Angiotensin II is a key component of this system, and its effects on blood vessels and the kidneys are critical in maintaining homeostasis.
**Correct Answer:** D.