Question

Write two functions of juxtaglomerular apparatus.

Answer 1

Hint: It is an apparatus which is located next to glomerulus. It is the structure in the kidney which regulates the function of nephrons. It consists of cells which secrete renin. It regulates the flow of blood in the kidney.

Complete answer:
To solve this question, we must know about the function of juxtaglomerular apparatus.

The nephrons are the structural and functional unit of the kidney. It helps in maintaining the homeostasis of the body by excreting excess water and other metabolic wastes from the body. The kidney comprises juxtaglomerular apparatus which regulate the function of nephrons. It also helps in maintaining the flow of blood through the kidney.

Structure of Juxtaglomerular apparatus-The juxta glomerular apparatus is made up of asymmetrical large granular cells in the wall of the afferent arteriole near the entry of the nephron. It is also made up of mesangial cells.

Function:
1.The juxtaglomerular apparatus secretes renin. The renin is sensitive to the flow of blood. When the blood pressure decreases, it activates the renin secreting cells which helps in maintaining the constant flow of blood through the nephron. The blood pressure is lowered due to sodium or water loss.
2.The mesangial cells secrete the extracellular matrix which contains fibronectin, laminin, collagens.

Note: The hypersecretion of renin activates the renin-angiotensin system. The renin and angiotensin (secreted by liver) is in inactivated state until it combines to form RAS complex.. This system increases the flow of blood through the nephron. This leads to hypertension. It influences the cardiac output.