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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 mammalian kidney, they follow two markedly different courses, depending on the location of the glomeruli from which they arise. In the mammalian kidney, about 15% of glomeruli lie close to the boundary between the renal cortex and renal medulla and are known as juxtamedullary glomeruli. The rest are simply undifferentiated cortical ...
The glomerulus is a tuft of capillaries located within Bowman's capsule within the kidney. [2] Glomerular mesangial cells structurally support the tufts. Blood enters the capillaries of the glomerulus by a single arteriole called an afferent arteriole and leaves by an efferent arteriole. [3]
The venous drainage of the kidney large mirrors its arterial supply, except that there are no segmental veins. [4] The stellate veins arise from the capillaries, then drain successively through interlobular veins and interlobar veins until these converge from across the kidney to form the renal vein for that kidney.
The vascular pole is a location of the glomerulus. At the vascular pole, the afferent arterioles and efferent arterioles enter and leave the glomerulus in the Bowman's capsule. The tubular pole is at the other end opposite to the vascular pole.
Mechanosensory nerves of the kidney are activated by stretching of the tissue of the renal pelvis, which can occur with an increase in the rate of urine flow from the kidney, resulting in a reflex decrease in the activity of efferent sympathetic nerves. That is, activation of the afferent nerves in the kidney suppresses the activity of the ...
The afferent arterioles, then, enter Bowman's capsule and end in the glomerulus. From each glomerulus, the corresponding efferent arteriole arises and then exits the capsule near the point where the afferent arteriole enters. Distally, efferent arterioles branch out to form dense plexuses (i.e., capillary beds) around their adjacent renal tubules.
Central to the physiologic maintenance of GFR is the differential basal tone of the afferent and efferent arterioles (see diagram). In other words, the filtration rate is dependent on the difference between the higher blood pressure created by vasoconstriction of the input or afferent arteriole versus the lower blood pressure created by lesser ...