The part of the autonomic nervous system originating in the brainstem and the lower part of the spinal cord that, in general, inhibits or opposes the physiological effects of the sympathetic nervous system, as in tending to stimulate digestive secretions or slow the heart.
The part of the autonomic nervous system that tends to act in opposition to the sympathetic nervous system, as by slowing down the heartbeat and dilating the blood vessels. It regulates the function of many glands, such as those that produce tears and saliva, and stimulates motility and secretions of the digestive system. Compare sympathetic nervous system.
