In order for blood to always flow unidirectionally through a closed circulatory system, the ________.
A) blood vessels furthest from the heart must have valves
B) capillaries must have a thick endothelium
C) arteries must be elastic
D) pressure in all vessels must be equal

Question

Quizplus · Accepted Answer

Valves in blood vessels prevent backflow of blood and ensure that it flows in one direction through the closed circulatory system. Capillaries are not involved in maintaining unidirectional flow. Elasticity of arteries helps them to withstand the pressure created by blood flow, but it does not ensure unidirectional flow. Pressure in vessels will not always be equal, but valves can compensate for any differences and maintain proper flow direction.

In Order for Blood to Always Flow Unidirectionally Through a Closed