What are juxtaglomerular cells primarily responsible for?

Juxtaglomerular cells are specialized cells located in the walls of the afferent arterioles of the nephron in the kidney. Their primary function is to detect changes in blood pressure and sodium levels. When blood pressure drops or sodium concentration decreases, these cells respond by releasing the enzyme renin into the bloodstream.

Renin plays a critical role in the renin-angiotensin-aldosterone system (RAAS), which helps regulate blood pressure and fluid balance in the body. By detecting changes in blood pressure and sodium levels, juxtaglomerular cells initiate a cascade of responses aimed at restoring normal blood pressure and maintaining homeostasis.

The other functions listed are not the primary role of juxtaglomerular cells. For example, urine production is carried out by the nephrons as a whole, while body temperature regulation is primarily managed by the hypothalamus and not by juxtaglomerular cells. Although juxtaglomerular cells do play a role in hormone secretion—specifically renin—their principal function is centered around monitoring and responding to changes in blood pressure and sodium concentration.