Question

What is macula densa?

Answer 1

Macula densa:

1. Macula densa is a type of cell that is located in the cell lining of the distal convoluted tubule (DCT).
2. It helps in regulating important renal processes such glomerular filtration rate, renal blood flow, and renin release.
3. The salt content (NaCl) in DCT, affects these cells.

Function:

1. It causes juxtaglomerular cells to release more renin.
2. It lowers blood flow resistance in the afferent arterioles, bringing the glomerular filtration rate back to normal.
3. Renin Specialized smooth muscle cells called juxta-glomerular cells are found in the afferent arteriole, which carries blood to the glomerulus.
4. The kidney is triggered to release renin when it gets a little amount of blood (low glomerular blood flow).
5. The primary stimuli for renin synthesis include changes in sodium concentration in the distal convoluted tubule and reduction in renal plasma flow and blood pressure, which together lead to a decrease in the hydrostatic pressure of the afferent arteriole.