The venous system serves as which major reservoir in the circulatory system?

The venous system serves as which major reservoir in the circulatory system?

• A. Arterial system
• B. Venous system
• C. Capillary beds
• D. Lymphatic system

Answer: (B)

Veins function as the body's reservoir for blood because they are highly compliant, so their walls can stretch to hold a large volume with only small increases in pressure. This capacitance means that, at rest, the venous system contains the majority of circulating blood, ready to be mobilized quickly to the heart to maintain venous return and cardiac output when needed. The other vessels aren’t structured to store large volumes: arteries carry blood under high pressure to tissues, capillary beds are the sites of exchange, and the lymphatic system handles interstitial fluid and immune components rather than circulating blood volume.

Veins function as the body's reservoir for blood because they are highly compliant, so their walls can stretch to hold a large volume with only small increases in pressure. This capacitance means that, at rest, the venous system contains the majority of circulating blood, ready to be mobilized quickly to the heart to maintain venous return and cardiac output when needed. The other vessels aren’t structured to store large volumes: arteries carry blood under high pressure to tissues, capillary beds are the sites of exchange, and the lymphatic system handles interstitial fluid and immune components rather than circulating blood volume.