Angiotensin II causes A/E:
**Core Concept**
Angiotensin II is a potent vasoconstrictor and a key component of the renin-angiotensin-aldosterone system (RAAS), which regulates blood pressure and fluid balance. It exerts its effects through interaction with specific receptors in the cardiovascular system.
**Why the Correct Answer is Right**
Angiotensin II binds to the AT1 receptor, leading to vasoconstriction, increased blood pressure, and stimulation of the release of aldosterone from the adrenal cortex, which promotes sodium retention and water reabsorption. This results in increased blood volume and blood pressure. Additionally, angiotensin II stimulates the release of vasopressin (ADH) from the posterior pituitary gland, further contributing to water reabsorption and increased blood pressure.
**Why Each Wrong Option is Incorrect**
**Option A:** Not directly related to angiotensin II's primary effects.
**Option B:** While angiotensin II does have some effects on cardiac function, its primary action is not on cardiac contractility.
**Option C:** Angiotensin II does not directly stimulate the release of antidiuretic hormone (ADH) from the hypothalamus; instead, it stimulates the release of ADH from the posterior pituitary gland.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) can be used to counteract the effects of angiotensin II in conditions like hypertension and heart failure.
**Correct Answer:** C.