Question

Juxta glomerular apparatus in kidney releases Renin, when a person is ________

• A. dehydrated and has high BP
• B. hydrated and with high BP
• C. hydrated and with low BP
• D. dehydrated and with low BP

Hint:

Renin rule: Low BP or low volume → Renin release → BP increases.

Answer 1

The Correct Option is D

Concept:
The juxtaglomerular apparatus (JGA) regulates blood pressure through the renin-angiotensin-aldosterone system (RAAS).

Step 1: Understand renin release. Renin is released when:
• Blood pressure is low
• Blood volume is low (dehydration)
• Sodium ion concentration is low

Step 2: Effect of renin. Renin initiates a cascade: \[ \text{Renin} \rightarrow \text{Angiotensin II} \rightarrow \text{Vasoconstriction + Aldosterone release} \] This increases blood pressure.

Step 3: Analyze options.
• (A) Dehydrated + high BP → Renin not released $\times$
• (B) Hydrated + high BP → No need for renin $\times$
• (C) Hydrated + low BP → Partial mismatch $\times$
• (D) Dehydrated + low BP → Correct condition \checkmark

Step 4: Conclusion. \[ \text{Renin is released during dehydration and low blood pressure} \]