Blood Pressure, Dr. D. Penney

Characteristics of the Veins:

  • Venous return = arterial outflow (William Harvey, 1628)

  • Hold 60 - 70% of body's blood volume

  • Blood pooling occurs below heart level

  • Valves in deep muscle and cutaneous veins

  • CNS control of venomotion

  • Usually collapsed above heart level

  • Flat when empty; pressure approximately zero until x-section is circular, then pressure increases sharply

  • Capacity for venomotor tone is reduced by bed rest, alcohol, fatigue, etc.

  • Pulse, retrograde from the heart, in systemic veins

  • Return

    Back to Index