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Veins have a much higher compliance than arteries (largely due to their thinner walls.) Veins which are abnormally compliant can be associated with edema. Pressure stockings are sometimes used to externally reduce compliance, and thus keep blood from pooling in the legs.
Skeletal muscle pump: Rhythmical contractions of limb muscles as occurs during normal activity such as walking, running, and swimming, promotes venous return.; Decreased venous capacitance: Sympathetic activation of veins decreases venous compliance, increases vasomotor tone, increases central venous pressure and promotes venous return indirectly by augmenting cardiac output through the Frank ...
Veins are described as the "capacitance vessels" of the body because over 70% of the blood volume resides in the venous system. Veins are more compliant than arteries and expand to accommodate changing volume. [31]
The narrowing of blood vessels leads to an increase in peripheral resistance, thereby elevating blood pressure. While vasoconstriction is a normal and essential regulatory mechanism for maintaining blood pressure and redistributing blood flow during various physiological processes, its dysregulation can contribute to pathological conditions.
Veins have less smooth muscle and connective tissue and wider internal diameters than arteries. Because of their thinner walls and wider lumens they are able to expand and hold more blood. This greater capacity gives them the term of capacitance vessels. At any time, nearly 70% of the total volume of blood in the human body is in the veins. [3]
When moving upright, the blood volume moves to the peripheral parts of the body. To combat this, the muscles involved in standing contract and help to bring venous blood volume to the heart. [1] [2] The pump is important in affecting the central and local supply of blood output. [3]
Normal EABV exists when the ratio of cardiac output to peripheral resistance maintains venous return and cardiac output at normal levels. EABV can be reduced, therefore, by factors which reduce actual arterial blood volume (hemorrhage, dehydration), increase arterial vascular capacitance (cirrhosis, sepsis) or reduce cardiac output (congestive ...
Mean systemic pressure increases if there is an increase in blood volume or if there is a decrease in venous compliance (where blood is shifted from the veins to the arteries). An increase in mean systemic pressure is reflected in a shift of the vascular function curve to the right. Mean systemic pressure is decreased by a decrease in blood ...