The kidneys have built-in mechanisms for the regulation of glomerular filtration rate. One such efficient mechanism is carried out by juxta glomerular apparatus (JGA). JGA is a special sensitive region formed by cellular modifications in the distal convoluted tubule and the afferent arteriole at the location of their contact. A fall in GFR can activate the JG cells to release renin which can stimulate the glomerular blood flow and thereby the GFR back to normal.
NTA tests your understanding of how the juxtaglomerular apparatus (JGA) automatically maintains a steady glomerular filtration rate through the renin-release mechanism. When GFR drops, JG cells release renin, which increases glomerular blood flow and restores GFR to normal—a negative feedback system. Students commonly confuse renin's role with other hormones like aldosterone or make wrong associations about which cells release renin. Remember: JGA is the sensor, JG cells release renin when GFR falls, and renin stimulates blood flow to restore filtration, not regulate blood pressure directly at this point.
This paragraph was tested 3 times in NEET.
The Juxta Glomerular Apparatus (JGA) is formed by cellular modifications in
Assertion (A): Juxta Glomerular Apparatus (JGA) plays an important role in regulation of glomerular filtration rate (GFR). Reason (R): A fall in GFR can activate the JG cells to release renin which stimulates glomerular blood flow, restoring GFR. Choose the correct option:
Arrange the events of the Renin-Angiotensin mechanism: (A) Activation of JG cells and renin release (B) Angiotensin II activates aldosterone release (C) Fall in glomerular blood pressure (D) Na+ and water reabsorption in DCT (E) Angiotensinogen → Angiotensin I → Angiotensin II
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