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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 ...
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.
An arteriole is a small-diameter blood vessel in the microcirculation that extends and branches out from an artery and leads to capillaries. [1] Arterioles have muscular walls (usually only one to two layers of smooth muscle cells) and are the primary site of vascular resistance. The greatest change in blood pressure and velocity of blood flow ...
[4] [8] [9] In hypertension only the afferent arteriole is affected, while in diabetes mellitus, both the afferent and efferent arteriole are affected. [8] [9] It is also seen in retina and brain, [10] where retinal infarcts and small brain infarcts, or lacunes can occur. Cause
In addition to carrying oxygen, blood also carries hormones, and nutrients to the cells of a body and removes waste products. [17] Blood vessels do not actively engage in the transport of blood (they have no appreciable peristalsis). Blood is propelled through arteries and arterioles through pressure generated by the heartbeat. [18]
Note 2: Also called the cortical radiate arteries. The interlobular artery also supplies to the stellate veins. Note 3: The efferent arterioles do not directly drain into the interlobular vein, but rather they go to the peritubular capillaries first. The efferent arterioles of the juxtamedullary nephron drain into the vasa recta.
However, this reduces blood flow to the kidneys. To compensate, the efferent arterioles constrict to a greater degree than the other arteries, in response to increased levels of angiotensin II. Pressure in glomerular capillaries is therefore maintained and glomerular filtration rate remains adequate.
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 capillaries consist of a tube lined by endothelial cells with a central lumen. The gaps between these endothelial cells are called fenestrae.