juxtaglomerular apparatus development

Definition

Target type: biologicalprocess

The process whose specific outcome is the progression of the juxtaglomerular apparatus over time, from its formation to the mature structure. The juxtaglomerular apparatus is an anatomical structure that lies adjacent to the glomerulus and regulates kidney function. [GOC:mtg_kidney_jan10]

The juxtaglomerular apparatus (JGA) is a specialized structure located at the point where the afferent arteriole enters the renal corpuscle. It plays a crucial role in regulating blood pressure and electrolyte balance. The development of the JGA involves a complex interplay of signaling pathways and cell-cell interactions, beginning during fetal development and continuing throughout life.

**Early Development:**

* **Mesonephric tubule differentiation:** During fetal development, the mesonephric tubules differentiate to form the nephrons, the functional units of the kidney. The proximal and distal tubules arise from the mesonephric tubules, while the glomerulus develops as a specialized capillary bed surrounded by Bowman's capsule.
* **Differentiation of smooth muscle cells:** The afferent arteriole, the vessel that supplies blood to the glomerulus, contains smooth muscle cells that express renin, a key enzyme in the renin-angiotensin-aldosterone system. The development of these smooth muscle cells is regulated by factors such as angiotensin II and transforming growth factor-beta (TGF-β).
* **Formation of the macula densa:** The macula densa is a specialized group of epithelial cells located in the distal convoluted tubule, where it comes into contact with the afferent arteriole. It senses changes in sodium chloride concentration in the tubular fluid, playing a crucial role in regulating renin secretion.

**Maturation and Function:**

* **Interaction between macula densa and juxtaglomerular cells:** The macula densa communicates with the juxtaglomerular cells (smooth muscle cells of the afferent arteriole) through paracrine signaling pathways. When the macula densa senses a decrease in sodium chloride concentration, it releases signaling molecules that stimulate renin release from the juxtaglomerular cells.
* **Renin secretion and the renin-angiotensin-aldosterone system:** Renin, secreted by the juxtaglomerular cells, initiates the renin-angiotensin-aldosterone system (RAAS), a cascade of hormonal events that ultimately leads to increased blood pressure and sodium retention.
* **Regulation of blood pressure and electrolyte balance:** The JGA's role in regulating renin secretion is essential for maintaining blood pressure and electrolyte balance. By controlling the RAAS, it helps adjust blood volume, renal blood flow, and sodium reabsorption.

**In summary, the development of the juxtaglomerular apparatus involves complex interactions between different cell types, signaling pathways, and growth factors. This process ensures that the JGA is properly formed and functions optimally to regulate blood pressure and electrolyte balance.**'"

Proteins (1)

Compounds (44)