Juxtaglomerular cell

Juxtaglomerular cell: functions and role in the regulation of blood pressure

The juxtaglomerular cell (abbreviated JG cell) is an important component of the renal blood pressure regulation system. It is located in the wall of the afferent arteriole, next to the macula densa, which is located at the beginning of the renal tubular system.

JG cells have a unique set of granules containing renin, an enzyme that plays a key role in the regulation of blood pressure through participation in the renin-angiotensin system. In addition, JG cells can secrete sodium and potassium, also participating in the regulation of electrolyte balance and metabolism.

The role of JG cells in the regulation of blood pressure is as follows: when pressure in the afferent arteriole decreases (for example, when circulating blood volume decreases), JG cells begin to release renin into the blood. Renin in turn is converted to angiotensin I, which is converted to angiotensin II by the action of angiotensin-converting enzyme (ACE). Angiotensin II constricts arterioles, increasing total peripheral resistance and increasing blood pressure.

In addition, angiotensin II stimulates the release of aldosterone, a hormone that increases the reabsorption of sodium and water in the renal tubules, increasing circulating blood volume and thereby increasing blood pressure.

It is important to note that JG cells also play a role in the autoregulation mechanism of renal blood flow, which helps maintain a constant volume of blood entering the kidneys and therefore stable blood pressure levels.

In conclusion, JG cells play an important role in regulating blood pressure and electrolyte balance in the body. When their function is impaired, various diseases can occur, such as hypertension and chronic renal failure. Therefore, further studies of the mechanisms of functioning of JG cells may be useful for the development of new methods for the treatment and prevention of these diseases.

Juxta cells are located predominantly in the head at one mouth of the juxta vessels (Fig. 45). Their number varies slightly; It is believed that there should be 5-10 of them here. However, it is known that in certain cases the juxta may be absent - and the renal corpuscle is located near the vessels at a great distance from the junction of the proximal and distal tubules. Juxta refers to the epithelium of the collecting ducts. It also has a granular endoplasmic reticulum. The cell length reaches about 35 µm (in the head it can reach 250 µm), and the width is 17 µm. Along the periphery there are single microvilli, but they are very short, about 8-12 of them per surface. These cells have no processes[2].

There are 6-7 microvilli in the juxtar head. There are 8 microvilli in the lateral filaments; they are relatively more numerous than in the head. The glandular sections of the juxte are no different from those in the proximal convoluted tubule. The number of cells in this area of ​​the kidney is small.