It is one of the two divisions of the autonomic nervous system, the other being the sympathetic nervous system.
parasympathetic nervous system. n. 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. Parasympathetic nervous system. The division of the autonomic (involuntary or unwilled) nervous system that slows heart rate, increases digestive and gland activity, and relaxes the sphincter muscles that close off body organs. Noun. 1. parasympathetic nervous system-originates in the brain stem and lower part of the spinal cord; opposes physiological effects of the sympathetic nervous system: stimulates digestive secretions; slows the heart; constricts the pupils; dilates blood vessels. parasympathetic. The part of the autonomic nervous system originating in the brain stem 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, slow the heart, constrict the pupils, and dilate blood vessels. 1. parasympathetic nervous system-originates in the brain stem and lower part of the spinal cord; opposes physiological effects of the sympathetic nervous system: stimulates digestive secretions; slows the heart; constricts the pupils; dilates blood vessels. parasympathetic. The parasympathetic nervous system is one of the two main divisions of the autonomic nervous system (ANS). Its general function is to control homeostasis and the body's rest-and-digest response. The sympathetic nervous system (SNS) is one of two main divisions of the autonomic nervous system (ANS). The parasympathetic nervous system (PNS) controls homeostasis and the body at rest and is responsible for the body's rest and digest function. The sympathetic nervous system (SNS) controls the body's responses to a perceived threat and is responsible for the fight or fligh Parasympathetic nervous system. Definition. noun. A division of the (vertebrate) autonomic nervous system whose physiological effects are mostly in opposition to those of the sympathetic nervous system; e.g. it is involved in the slowing of the heart beat and relaxing the muscles. The Autonomic Nervous System. The autonomic nervous system, or ANS, is the portion of the nervous system that regulates involuntary processes. In other words, these are processes that are not under conscious control. The ANS is divided into two divisions: the parasympathetic and the sympathetic nervous systems. The sympathetic nervous system, also called 'fight-or-flight' activation, is the segment that prepares the body for emergency situations. Since this is the normal state of the body, the parasympathetic system is more active than the sympathetic system in controlling bodily functions. Neurons in the parasympathetic nervous system utilize acetylcholine, a neurotransmitter for cell-to-cell communication. Unsourced material may be challenged and removed. (November 2011). The parasympathetic nervous system (usually abbreviated PSNS, not PNS, to avoid confusion with the peripheral nervous system [PNS]) is one of the two divisions of the autonomic nervous system, the other being the sympathetic nervous system.  The part of the autonomic nervous system originating in the brain stem 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, slow the heart, constrict the pupils, and dilate blood vessels. Noun. 1. parasympathetic nervous system-originates in the brain stem and lower part of the spinal cord; opposes physiological effects of the sympathetic nervous system: stimulates digestive secretions; slows the heart; constricts the pupils; dilates blood vessels. parasympathetic. Parasympathetic nervous system: The part of the involuntary nervous system that serves to slow the heart rate, increase intestinal and glandular activity, and relax the sphincter muscles. The parasympathetic nervous system, together with the sympathetic nervous system, constitutes the autonomic nervous system. 
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parasympathetic division definition