Question

Juxtaglomerular apparatus contains all the following except
A) Granular cells
B) Macula densa
C) Agranular polkissen cells
D) Ducts of bellini

Answer 1

Hint : It is the collecting duct system of the kidney that consists of a series of tubules and ducts that physically connects nephrons.

Complete answer :
Juxtaglomerular is a structure in the kidney that regulates the function of nephrons (functional unit of kidney). It consists of 3 types of cells: 1. Macula densa, a part of the distal convoluted tubule of the same nephron. 2. Granular cells which secrete renin. 3. Mesangial cells. Granular cells are the cells that are found in the kidney that helps in synthesizing, store and secrete the renin enzyme. Juxtaglomerular apparatus also contain Macula densa cells that generate paracrine chemical signals in the juxtaglomerular apparatus to control vital kidney functions. Agranular polkissen cells are also called Lacis cells and they are light staining pericytes in the kidney found outside the glomerulus. The main function of juxtaglomerular apparatus is to regulate the blood pressure and rate of filtration of glomerulus.

Ducts of bellini consist of tubules and ducts that physically connect nephrons to renal pelvis.The ducts of bellini (collecting duct system)is the final component of the kidney to influence the body’s electrolyte and fluid balance. So ,from the above explanation it is concluded that Ducts of Bellini are not found in juxtaglomerular apparatus.

Thus, the correct answer is option D. i.e., Ducts of Bellini.

Note : The juxtaglomerular apparatus is named because it is next to Juxta. The ducts of bellini were named after Lorenzo Bellini, he was a physician and anatomist who described the collecting, or excretory, tubules of the kidney.