| Afferent arterioles | |
|---|---|
 Scheme ofrenal tubules and its vascular supply. (Label "Afferent vessel" is visible in upper left.) | |
 Distribution of bloodvessels in cortex of kidney. | |
| Details | |
| From | interlobular artery |
| Supplies | glomerular capillaries |
| Identifiers | |
| Latin | arteriola glomerularis afferens |
| TA98 | A08.1.03.005 |
| FMA | 272216 77042, 272216 |
| Anatomical terminology | |
Theafferent arterioles are a group ofblood vessels that supply thenephrons in manyexcretory systems. They play an important role in the regulation ofblood pressure as a part of thetubuloglomerular feedback mechanism.
The afferent arterioles branch from therenal artery, which supplies blood to thekidneys.
The afferent arterioles later diverge into thecapillaries of theglomerulus.
When renal blood flow is reduced (indicatinghypotension) or there is a decrease in sodium or chloride ion concentration, themacula densa of thedistal tubule releasesprostaglandins (mainly PGI2 and PGE2) andnitric oxide, which cause thejuxtaglomerular cells lining the afferent arterioles to releaserenin, activating therenin–angiotensin–aldosterone system, to increase blood pressure and increase reabsorption of sodium ions into the bloodstream viaaldosterone.[1]
The macula densa cell can also increase the blood pressure of the afferent arterioles by decreasing the synthesis ofadenosine orATP.[1]
If the efferent arterioles are constricted then the blood pressure in the capillaries of the kidneys will increase.
