All of the following are true except

Options

A. Renin is secreted by Juxta glomerular cells
B. A fall in GFR can activate the JG cells to release renin which can stimulate the glomerular blood flow.
C. It releases renin which converts angiotensinogen to angiotensin II
D. Angiotensin II is a potent vasoconstrictor

Answer

To solve the question, we need to analyze the statements provided and identify which one is false.

### Step-by-Step Solution:

1. **Identify the Secretory Source of Renin**:
- Renin is secreted by the juxtaglomerular (JG) cells of the kidney. This statement is true.

2. **Understand the Role of GFR**:
- A fall in the Glomerular Filtration Rate (GFR) does indeed activate the juxtaglomerular cells to release renin. This statement is also true.

3. **Renin's Function**:
- Renin converts angiotensinogen (produced by the liver) into angiotensin I. This statement is true.

4. **Conversion of Angiotensin I to Angiotensin II**:
- Angiotensin I is then converted to angiotensin II by the action of enzymes, primarily in the lungs. Angiotensin II is a potent vasoconstrictor. This statement is true.

5. **Identify the False Statement**:
- The only false statement in the context is that "renin converts angiotensinogen to angiotensin II." In reality, renin converts angiotensinogen to angiotensin I, and then angiotensin I is converted to angiotensin II by enzymes in the lungs.

### Conclusion:
The false statement among the options provided is the one that claims renin directly converts angiotensinogen to angiotensin II.

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