- contain the highest proportion of the blood in the cardiovascular system.
-The blood volume contained in the veins is called the unstressed volume.
- are innervated by autonomic fibers.
B. Velocity of blood flow
- can be expressed by the following equation:
v = velocity (cm/sec) Q = blood flow (ml/min) A = cross-sectional area (cm2)
- Velocity is directly proportional to blood flow and inversely proportional to the cross-sectional area at any level of the cardiovascular system.
- For example, blood flow velocity is higher in the aorta (small cross-sectional area) than in the sum of all of the capillaries (large cross-sectional area). The lower velocity of blood flow in the capillaries optimizes conditions for exchange of substances across the capillary wall.
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