Question

multiple choice question
what is the function of precapillary sphincters?
o they control blood flow into the capillary network.
o they allow large molecules and cells to exit the network.
o they provide a lipid transport mechanism.
o they absorb carbon dioxide from the tissues.

Explanation:

Precapillary sphincters are smooth - muscle rings located at the entrance of capillaries. They can contract or relax to regulate the amount of blood flowing into the capillary network.

Answer:

They control blood flow into the capillary network.