Reflex control of regional circulations in humans.

This study of autonomic control of the peripheral vascular system deals with reflex control of regional circulations, vasoconstriction in the upright posture, disturbances in the normal regulation caused by dysautonomia and spinal cord transection, regional vasomotor responses to thermal stress, and the overall sympathetic nerve activity in humans under stress. Data presented describe local and overall reactions that occur in normal and abnormal states. In varieties of stresses, humans adjust by increasing sympathetic nerve outflow in a highly predictable fashion. However, powerful local or humoral influences, such as those generated by hypoxia, hemorrhage, etc., are pitted against neurogenic vasoconstriction so that prediction of responses is very difficult.