The renin-angiotensin mechanism to increase blood pressure involves organs in the following order.

Options

A. Kidney- Liver - Lungs - Adrenal gland - Kidney
B. Kidney- Lungs - Liver - Adrenal gland - Kidney
C. Kidney- Liver - Adrenal gland - Lungs - Kidney
D. Kidney- Lungs - Adrenal gland - Liver - Kidney

Answer

To solve the question regarding the renin-angiotensin mechanism to increase blood pressure and the order of organs involved, we can break it down into the following steps:

### Step-by-Step Solution:

1. **Initiation in the Kidney**: The process begins in the kidneys. When blood pressure decreases, the kidneys detect this drop and respond by releasing an enzyme called renin.

**Hint**: Remember that the kidneys are the first responders to changes in blood pressure.

2. **Conversion in the Liver**: Renin then acts on a protein produced by the liver known as angiotensinogen. Renin converts angiotensinogen into angiotensin I.

**Hint**: Think of the liver as the source of the precursor that renin acts upon.

3. **Activation in the Lungs**: Angiotensin I is then transported to the lungs, where it encounters an enzyme known as angiotensin-converting enzyme (ACE). This enzyme converts angiotensin I into angiotensin II.

**Hint**: The lungs play a crucial role in the conversion process, highlighting their importance in the mechanism.

4. **Action on the Adrenal Gland**: Angiotensin II has several effects, one of which is to stimulate the adrenal glands to release aldosterone, a hormone that helps regulate blood pressure.

**Hint**: The adrenal glands are key players in hormone production that affects blood volume and pressure.

5. **Final Action in the Kidney**: Aldosterone then acts on the kidneys, specifically on the distal convoluted tubule and collecting ducts, promoting the reabsorption of sodium (Na+) and water. This reabsorption increases blood volume and, consequently, blood pressure.

**Hint**: The kidneys are involved again, completing the cycle of the renin-angiotensin mechanism.

### Final Order of Organs Involved:
- **Kidney → Liver → Lungs → Adrenal Gland → Kidney**

### Conclusion:
The correct order of organs involved in the renin-angiotensin mechanism to increase blood pressure is:
**Kidney, Liver, Lungs, Adrenal Gland, Kidney.**