Afferent arteriole

Definition

The afferent arteriole is a small blood vessel that supplies blood to the glomerulus of the nephron in the kidney. It plays a crucial role in regulating blood pressure and filtration rate within the glomerulus.

5 Must Know Facts For Your Next Test

1. The afferent arteriole has a larger diameter than the efferent arteriole, which helps create high pressure for filtration.
2. It contains smooth muscle cells that can constrict or dilate to control blood flow into the glomerulus.
3. Renin is released from juxtaglomerular cells located in the walls of afferent arterioles when blood pressure drops.
4. Constriction of the afferent arteriole reduces renal blood flow and glomerular filtration rate (GFR).
5. Dilation of the afferent arteriole increases renal blood flow and GFR, enhancing urine formation.

Review Questions

• What is the primary function of the afferent arteriole in kidney physiology?
• How does constriction of the afferent arteriole affect glomerular filtration rate?
• Why do juxtaglomerular cells release renin, and where are these cells located?

Related terms

glomerulus: A network of capillaries in the nephron where blood filtration begins.

efferent arteriole: A small blood vessel that carries filtered blood away from the glomerulus.

juxtaglomerular apparatus: A structure near each glomerulus that helps regulate kidney function by releasing renin.