Concept
Version 6
Created by Boundless
Blood Flow Through the Body
![Precapillary sphincters](../../../../../../../../../figures.boundless-cdn.com/19680/full/figure-40-04-01ab.jpg)
Precapillary sphincters
(a) Precapillary sphincters are rings of smooth muscle that regulate the flow of blood through capillaries; they help control the blood flow to where it is needed. (b) Valves in the veins prevent blood from moving backward.
Source
Boundless vets and curates high-quality, openly licensed content from around the Internet. This particular resource used the following sources:
"OpenStax College, Blood Flow and Blood Pressure Regulation. October 17, 2013."
http://cnx.org/content/m44806/latest/Figure_40_04_01ab.png
OpenStax CNX
CC BY 3.0.