Renin is released from JGA in response to

Options

A. High glomerular blood pressure
B. Fall in glomerular bool flow
C. High GFR
D. Decrease in osmolarity

Answer

**Step-by-Step Solution:**

1. **Understanding Renin and its Source**: Renin is a hormone released from the juxtaglomerular apparatus (JGA) in the kidneys. The JGA is located at the junction of the distal convoluted tubule (DCT) and the afferent arteriole.

2. **Identifying the Stimulus for Renin Release**: Renin is released in response to specific physiological changes. One primary stimulus is a decrease in blood pressure (BP) or blood volume.

3. **Mechanism of Action**: When there is a decrease in blood volume or blood pressure, the glomerular filtration rate (GFR) also decreases. This decrease in GFR is detected by the cells of the JGA, which then stimulates the release of renin.

4. **Renin's Role in the Renin-Angiotensin-Aldosterone System (RAAS)**: Once released, renin acts on angiotensinogen, an inactive protein, converting it into angiotensin I. Angiotensin I is then converted to angiotensin II, which is a potent vasoconstrictor, helping to increase blood pressure.

5. **Further Actions of Angiotensin II**: Angiotensin II also stimulates the adrenal cortex to release aldosterone, which promotes sodium and water reabsorption in the kidneys, further helping to restore blood volume and pressure.

6. **Conclusion**: Therefore, renin is released from the juxtaglomerular apparatus in response to a fall in blood flow or blood pressure.

**Final Answer**: Renin is released from the JGA in response to a decrease in blood flow or blood pressure.

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