How does macula densa release renin?
How does macula densa release renin?
Macula-Densa Control of Renin Release Renin secretion depends on NaCl delivery to and reabsorption by the macula-densa cells at the end of the TAL. Inhibition of renin release occurs when solute delivery to this section of the renal tubule is high, and stimulation is associated with low solute delivery.
Do macula densa cells stimulate renin release?
Macula densa cells in the distal nephron, according to the classic paradigm, are salt sensors that generate paracrine chemical signals in the juxtaglomerular apparatus to control vital kidney functions, including renal blood flow, glomerular filtration, and renin release.
What stimulates macula densa cells?
A decrease in sodium chloride concentration initiates a signal from the macula densa that has two effects: (1) it decreases resistance to blood flow in the afferent arterioles, which raises glomerular hydrostatic pressure and helps return the glomerular filtration rate (GFR) toward normal, and (2) it increases renin …
What triggers macula densa cells to release prostaglandins?
An increase in macula densa cell calcium could activate phospholipase A2 to release arachidonic acid, the rate-limiting step in the formation of prostaglandins. Recent evidence suggests that the prostaglandin formed is PGE2, a potent stimulator for renin release.
What is the function of the macula densa?
Macula densa (MD) cells are chief cells within the kidney, playing key sensory and regulatory functions in the maintenance of body fluid, electrolyte homeostasis, and blood pressure.
What cells release renin?
juxtaglomerular cells
The main source of renin is the juxtaglomerular cells (JGCs), which release renin from storage granules. Besides the renin-angiotensin system (RAS) in the JGCs, there exist local RASs in various tissues.
What do macula densa cells respond to?
It is thought that the macula densa cells are sensory cells that respond to the sodium concentration in the fluid within the distal tubule and, perhaps, to the rate of fluid flow past them.
Where is renin produced and what stimulates its secretion?
Renin is secreted from juxtaglomerular kidney cells, which sense changes in renal perfusion pressure, via stretch receptors in the vascular walls. The juxtaglomerular cells are also stimulated to release renin by signaling from the macula densa.
What stimulates release of renin?
Renin is a proteolytic enzyme that is released into the circulation by the kidneys. Its release is stimulated by: sympathetic nerve activation (acting through β1-adrenoceptors) renal artery hypotension (caused by systemic hypotension or renal artery stenosis)
What is the function of the macula densa quizlet?
The macula densa cells monitor the NaCl content of the filtrate entering the distal convoluted tubule.
How is renin release stimulated?
How is renin secreted from the macula densa?
Macula-Densa Control of Renin Release The macula densa participates in the regulation of renin release from juxtaglomerular granular cells. Renin secretion depends on NaCl delivery to and reabsorption by the macula-densa cells at the end of the TAL.
What are the functions of the macula-densa?
Macula Densa 1 Reabsorption of Na + and Cl − ions in the macula densa. 2 Macula-Densa Control of Renin Release. The macula densa participates in the regulation… 3 7.01.11.1 Structure. The nephron segment between the macula densa and the first junction… 4 Renal Control of Blood Pressure. In the distal convoluted tubule is located…
What is the mechanism of GPR91 activation in macula densa?
GPR91 activation in macula densa cells is connected to the same signaling cascade as salt sensing; namely, the activation of p38 and ERK1/2 MAP kinases, COX-2, and the synthesis and release of PGE 2-triggered renin exocytosis.
How does the juxtaglomerular apparatus release renin?
Increased sodium and fluid delivery to the TAL and macula densa region signals the cells of the juxtaglomerular apparatus to release renin and produce angiotensin II locally as well as other vasoconstrictors, which act on the afferent arteriole to decrease filtration and thereby sodium and fluid delivery to the TAL and beyond.41
