Question

multiple choice question
what controls blood flow into the capillary network?

• tunica media
• plaque formation
• lumen resistance
• precapillary sphincters

Explanation:

Precapillary sphincters are rings of smooth muscle that regulate blood flow into capillary beds by constricting or relaxing. Tunica media is a vessel - wall layer, plaque formation is related to artery - blocking deposits, and lumen resistance affects overall blood flow but not specifically capillary entry.

Answer:

D. Precapillary sphincters