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