Multiple Choice
Which of the following is not a reason that veins need valves to prevent backflow, but arteries do not?
The smallest arterioles consist of only one layer (tunic), while the smallest venules have all 3 layers (tunics).
Some arterioles make direct contact with capillaries, but no venules do.
Arterioles deliver blood to capillaries while venules collect blood from capillaries.
Arterioles collect blood from capillaries while venules deliver blood to capillaries.