[Campbell Biology P.981] Based on Figure 42.12 and the accompanying text, what is the primar... | Practice Question

Based on Figure 42.12 and the accompanying text, what is the primary mechanism ensuring unidirectional blood flow towards the heart in veins, and what is a common consequence of its impaired function?

  • A: Arterial pulsation; decreased blood pressure in extremities.
  • B: Cardiac suction; increased blood pooling in the liver.
  • C: Skeletal muscle contraction and one-way valves; blood pooling and swelling in distal limbs.
  • D: Venous smooth muscle contraction; increased blood flow to the heart.

Explanation

Figure 42.12 and the text state that skeletal muscle contraction squeezes veins, and one-way valves prevent backflow, ensuring blood moves only toward the heart. A lack of muscular activity can cause blood pooling and swelling in distal limbs, such as the feet.