This flow is measured by the macula densa of the juxtaglomerular apparatus.

Macula densa, a group of cells in the kidney that stain darker histologically.

As the filtrate reaches the macula densa, less NaCl is reabsorbed.

The macula densa serves as the detector, while the glomerulus acts as the effector.

A decrease in sodium chloride concentration initiates a signal from the macula densa that has two effects:

Macula densa cells are columnar epithelium thickening of the distal tubule.

Further, the macula densa releases adenosine which causes constriction of the afferent arterioles.

It contains three components: the macula densa, juxtaglomerular cells, and extraglomerular mesangial cells.

If less Na+ is sensed by the macula densa, renin release by juxtaglomerular cells is increased.

A drop in the rate of flow past the macula densa implies a drop in renal filtration pressure.

The macula densa region of the kidney's juxtaglomerular apparatus is another modulator of blood osmolality.

One proposed mechanism is that delivery of sodium chloride to the macula densa intitiates purinergic signaling.

The cells of the macula densa are sensitive to the concentration of sodium chloride in the distal convoluted tubule.

The macula densa uses the composition of the tubular fluid as an indicator of GFR.

The point where DCT contacts afferent arteriole of renal corpuscle is called macula densa.

The macula densa's position enables it to rapidly alter glomerular resistance in response to changes in the flow rate through the distal nephron.

Precisely how the macula densa's detection of elevated sodium chloride leads to a decrease in GFR remains unknown.

Beta blockade, especially of the beta-1 receptor at the macula densa, inhibits renin release, thus decreasing the release of aldosterone.

The macula densa responds to changes in osmotic pressure through changes in the rate of chloride anion flow through the nephron.

Decrease in GFR is sensed as a decrease in Na levels by the macula densa.

The macula densa can sense this decrease and trigger an autoregulatory response to further increase reabsorption of ions and water in order to return blood pressure to normal.

The term he coined "Juxtaglomerular Complex" was used to denote the relationship of the renal tubular macula densa to the arteriolar granular cells.

When the macula densa detects an elevated GFR, it releases several molecules that cause the glomerulus to rapidly decrease its filtration rate.

The cells of the macula densa are taller and have more prominent nuclei than surrounding cells of the distal straight tubule (cortical thick ascending limb).

The close proximity and prominence of the nuclei cause this segment of the distal tubule wall to appear darker in microscopic preparations, hence the name macula densa.