| Efferent arteriole | |
|---|---|
 Scheme of renal tubule and its vascular supply. (Label "Efferent vessel" is visible in upper left.) | |
 Distribution of blood vessels in cortex of kidney. | |
| Details | |
| Source | glomerular capillaries |
| Identifiers | |
| Latin | arteriola glomerularis efferens capsulae renalis |
| TA98 | A08.1.03.006 |
| FMA | 272214 77043, 272214 |
| Anatomical terminology | |
The efferent arterioles are blood vessels that are part of the urinary tract of organisms. Efferent (from Latin ex + ferre) means "outgoing", in this case meaning carrying blood out away from the glomerulus. The efferent arterioles form a convergence of the capillaries of the glomerulus, and carry blood away from the glomerulus that has already been filtered. They play an important role in maintaining the glomerular filtration rate despite fluctuations in 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 glomeruli.