Juxtaglomerular cell

Juxtaglomerular cells (also known as granular cells) are specialized cells in the kidney that synthesize, store, and secrete the enzyme renin. They are located in the juxtaglomerular apparatus, a structure in the kidney that regulates the function of each nephron, the functional units of the kidney.

Structure

Juxtaglomerular cells are found in the wall of the afferent arteriole, and to a lesser extent the efferent arteriole, at the vascular pole of the renal corpuscle. They are modified smooth muscle cells that are closely associated with the macula densa, a group of specialized cells in the distal convoluted tubule, and extraglomerular mesangial cells.

Function

The primary function of juxtaglomerular cells is to secrete renin in response to certain stimuli. Renin is an enzyme that plays a crucial role in the renin-angiotensin-aldosterone system, a major regulatory system of renal blood flow and systemic blood pressure.

Clinical significance

Abnormalities in juxtaglomerular cells can lead to various renal disorders. For example, a decrease in the number of these cells can result in reduced renin production, leading to hypertension and renal failure. On the other hand, an increase in the number of juxtaglomerular cells can lead to excessive renin production, resulting in hypotension and edema.

See also

• Renal physiology
• Renal corpuscle
• Renin-angiotensin system

References

• 
  Juxtaglomerular cells
• 
  Renal corpuscle