CBSE Class 10 Answered

Juxtaglomerular apparatus (JGA) is present in the kidney. It is a complex of specialized sensory cells located in the afferent arteriole adjacent to the glomerulus. The juxtaglomerular apparatus is named for its proximity to the glomerulus. This apparatus regulates the function of each nephron. Its location is critical to its function in regulating renal blood flow and glomerular filtration rate. The three components of the apparatus are the macula densa, extraglomerular mesangial cells, and juxtaglomerular cells also known as granular cells.

Renin is the enzyme released by JG cells when there is a fall in glomerular blood flow. Renin converts angiotensinogen in blood to angiotensin I and further to angiotensin II. angiotensin II increases the glomerular blood pressure and also activates adrenal cortex to release aldosterone.