Tubuloglomerular feedback control is
useful for which one of the following?
a) GFR
b) Plasma sodium
c) Plasma volume
d) Determining tubular secretion
Correct Answer - A
Ans: A. GFR.
Tubuloglomerular feedback – Two components:
- Afferent arteriole feedback mechanism
- Usually referred as “Tubuloglomerular feedback”
- Efferent arteriole feedback mechanism.
Afferent arteriolar feedback mechanism: - Transmitter involved – Adenosine causing Ca2+ channel opening.
Efferent arteriolar feedback mechanism: - Activates renin-angiotensin system generating angiotensin II→
efferent arteriole constriction → ?ed GFR. - Feedback depends on juxtaglomerular apparatus & its specialized
cells.
- Macula densa – Specialized epithelium of distal tubule in close
contact with afferent arteriole