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When renal blood flow is reduced (indicating hypotension) or there is a decrease in sodium or chloride ion concentration, the macula densa of the distal tubule releases prostaglandins (mainly PGI2 and PGE2) and nitric oxide, which cause the juxtaglomerular cells lining the afferent arterioles to release renin, activating the renin–angiotensin–aldosterone system, to increase blood pressure ...
In the kidneys, angiotensin II constricts glomerular arterioles, having a greater effect on efferent arterioles than afferent. As with most other capillary beds in the body, the constriction of afferent arterioles increases the arteriolar resistance, raising systemic arterial blood pressure and decreasing the blood flow. However, the kidneys ...
The muscle tension in the afferent arteriole is modified based on the difference between the sensed concentration and a target concentration. [5] Vasodilation of the afferent arteriole, which results in increased glomerular filtration pressure and tubular fluid flow, occurs when MD cells detect a chloride concentration that is below a target value.
[6] [7] An increase in the salt concentration causes several cell signals (e.g. adenosine release) that leads to constriction of the adjacent afferent arteriole. This decreases the amount of blood coming from the afferent arterioles to the glomerular capillaries, and therefore decreases the amount of fluid that goes from the glomerular ...
Juxtaglomerular cells (JG cells), also known as juxtaglomerular granular cells are cells in the kidney that synthesize, store, and secrete the enzyme renin. [1] They are specialized smooth muscle cells mainly in the walls of the afferent arterioles (and some in the efferent arterioles) [citation needed] that deliver blood to the glomerulus.
Increases in systemic blood pressure will maintain renal perfusion pressure; however, constriction of the afferent and efferent glomerular arterioles will tend to restrict renal blood flow. The effect on the efferent arteriolar resistance is, however, markedly greater, in part due to its smaller basal diameter; this tends to increase glomerular ...
Mesangial cells are modified smooth muscle cells that lie between the capillaries. They regulate blood flow by their contractile activity and secrete extracellular matrix, prostaglandins, and cytokines. Mesangial cells also have phagocytic activity, removing proteins and other molecules trapped in the glomerular basement membrane or filtration ...
The sodium chloride levels in the urinary filtrate are sensed by the macula densa cells at the end of the ascending limb. When sodium levels are moderately increased, the macula densa releases ATP [12] and reduces prostaglandin E2 release [13] to the juxtaglomerular cells nearby. The juxtaglomerular cells in the afferent arteriole constrict ...