Angiotensin-II increases the blood volume by

Options

A. Singnlling PCT to reabsorb more NaCl and water
B. Stimulating adrenal gland to release aldosterone
C. By stimulating the release of ADH
D. More thean one option is correct

Answer

**Step-by-Step Solution:**

1. **Understanding Angiotensin II:**
- Angiotensin II is a peptide hormone that plays a crucial role in regulating blood pressure and fluid balance in the body. It is formed from angiotensin I through the action of the angiotensin-converting enzyme (ACE).

2. **Mechanisms of Action:**
- Angiotensin II increases blood volume and blood pressure through several mechanisms:
- **Signaling the Proximal Convoluted Tubule (PCT):** It promotes the reabsorption of sodium (Na+) and water (H2O) in the kidneys, specifically in the PCT.
- **Stimulating Aldosterone Release:** Angiotensin II stimulates the adrenal glands to release aldosterone, a hormone that increases sodium reabsorption in the kidneys, leading to increased water retention and blood volume.
- **Stimulating the Release of ADH:** It also promotes the secretion of antidiuretic hormone (ADH), which further enhances water reabsorption in the kidneys.

3. **Evaluating the Options:**
- **Option 1:** Signaling PCT to reabsorb more NaCl and water - This is correct.
- **Option 2:** Stimulating the adrenal gland to release aldosterone - This is also correct.
- **Option 3:** Stimulating the release of ADH - This is correct as well.
- **Option 4:** More than one option is correct - Since options 1, 2, and 3 are all correct, this option is also valid.

4. **Conclusion:**
- The correct answer is **Option 4**, as multiple mechanisms are involved in how angiotensin II increases blood volume.

---