Question

Juxtaglomerular apparatus is made up of
A. Juxtaglomerular cell, macula densa and lacis cell
B. Juxtaglomerular cell, purkinje cell and chief cell
C. Juxtaglomerular cell, lacis cell and myoepithelial cell
D. Juxtaglomerular cell, macula densa and argentaffin cell

Answer 1

Hint: Juxtaglomerular apparatus is made up of juxtaglomerular cell, macula densa and lacis cell. The juxtaglomerular apparatus is a region present between the afferent arteriole and the distal convoluted tubule.

Complete answer:
 The epithelial cells of the distal convoluted tubule that come in contact with the afferent and efferent arterioles are more dense than the other tubular cells and are collectively called the macula densa. Alongside the macula densa, the wall of afferent arteriole contains modified smooth muscle fibres called juxtaglomerular cells (JG cells).
Together with macula densa, they constitute the juxtaglomerular apparatus (JGA). Lacis cells bear processes forming the lace-like network which are present in the gaps between macula densa, efferent and afferent arterioles.
Juxtaglomerular apparatus is a special region formed by cellular modifications in the distal convoluted tubule and the afferent arteriole. The JGA becomes active when there is decrease in renal blood pressure or decrease in GFR.

So the correct answer is option A.

Note: Juxtaglomerular cells release renin which helps in the regulation of blood pressure and glomerular filtration rate. Renin converts protein angiotensinogen into peptide angiotensin. Angiotensin is a hormone that increases glomerular blood pressure through constricting different arterioles.