Nervous Control of the Pulmonary Circulation

Dr. Bayliss' statement implied that responses to adrenaline may be taken as sufficient evidence for sympathetic innervation and hence for autonomic control of the pulmonary vessels. In the ensuing decades detailed anatomi· cal studies of the pulmonary nerve supply clearly demonstrated that the pulmonary vascular bed is indeed well innervated by a variety of fiber types. But their contribution, if any, to regulation of blood flow through the lungs has proved difficult to establish. Even more elusive has been convincing evidence for neural control during normal physiological adjustments. Sen­ sory systems that might be involved in any postulated feedback system have been difficult to identify.