Figure 4. Metabolic mechanism of vasomotor control matches oxygen and substrate delivery supply by the vascular system to demand by skeletal muscle cells.

Figure 4

Metabolic mechanism of vasomotor control matches oxygen and substrate delivery supply by the vascular system to demand by skeletal muscle cells. Vasodilator metabolites such as adenosine, CO2, lactate, and potassium ions diffuse to arterioles to elicit changes in vasomotor tone. When skeletal muscle contraction is induced, the production of metabolites is increased, raising their concentration in the interstitial space. These byproducts of cellular metabolism diffuse from the myocytes to arterioles to induce vasodilation and thus increase blood flow to the active tissue. In addition, relaxation of terminal arterioles recruits capillaries, thereby increasing the surface area available for exchange of oxygen and nutrients. The vasodilator metabolites also diffuse into capillaries and are carried away from the active tissue by the flowing stream of blood. This establishes a new steady state concentration of metabolites, which maintains a vasodilated state so that oxygen delivery is matched to oxygen demand. When muscular activity ceases, metabolites are washed out of the tissues to establish lower steady state concentrations in the interstitium, which restores vascular caliber and lowers blood flow to levels seen in the resting state.

From: Chapter 3, Regulation of Vascular Tone in Skeletal Muscle

Cover of Skeletal Muscle Circulation
Skeletal Muscle Circulation.
Korthuis RJ.
San Rafael (CA): Morgan & Claypool Life Sciences; 2011.
Copyright © 2011 by Morgan & Claypool Life Sciences.

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