Question
Which component of auto-regulation of glomerular filtration acts on the efferent arteriole?
| A. |
Autonomous myogenic reflex
|
| B. |
Tubuloglomerular feedback
|
| C. |
Angiotensin II-mediated vasoconstriction
|
| D. |
None of the above
|
Show Answer
|
Correct Answer � C
Explanation
|
|
Mechanism of Auto-Regulation in the Glomerulus:
-
- The kidneys maintain a stable glomerular filtration rate (GFR) despite fluctuations in systemic blood pressure through autoregulation.
- Angiotensin II preferentially constricts the efferent arteriole, increasing glomerular capillary hydrostatic pressure and maintaining GFR.
Why Other Options Are Incorrect:
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- A. Autonomous myogenic reflex: Acts primarily on afferent arterioles to modulate blood flow into the glomerulus.
- B. Tubuloglomerular feedback: Mediated by macula densa cells, this mechanism regulates afferent arteriole constriction based on sodium chloride levels in the distal tubule.
