Psychogenic and neurogenic effects on the intact forearm vein of man.

By means of an elegant venous preparation the behavior of intact veins of man can be studied decisively. The superficial veins of man are extremely sensitive to the environment and the autonomic and central nervous systems. This report illustrates the response of an isolated venous segment of the forearm to various psychogenic and neurogenic stimuli, with change in tone of the smooth muscle of the venous segment being reflected by change in segmental venous pressure. It is shown that the superficial forearm veins can be conditioned and that they are extremely dynamic and certainly not passive conduits for returning blood to the heart.