parasympathetic nervous system part of the autonomic nervous system, the preganglionic fibers of which leave the central nervous system with cranial nerves III, VII, IX, and X and the first three sacral nerves; postganglionic fibers are distributed to the heart, smooth muscles, and glands of the head and neck, and thoracic, abdominal, and pelvic viscera ...
Parasympathetic tone synonyms, Parasympathetic tone pronunciation, Parasympathetic tone translation, English dictionary definition of Parasympathetic tone. 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...
autonomic tone is the background rate of activity of the ANS-it is the balance between the sympathetic and parasympathetic tone-parasympathetic tone maintains smooth muscle tone in the intestines and holds resting heart rate down to about 70-80 beats/minute
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Parasympathetic nervous system definition is - the part of the autonomic nervous system that contains chiefly cholinergic fibers, that tends to induce secretion, to increase the tone and contractility of smooth muscle, and to slow heart rate, and that consists of a cranial and a sacral part.
The parasympathetic nervous system (PSNS) is one of the two divisions of the autonomic nervous system (a division of the peripheral nervous system (PNS)), the other being the sympathetic nervous system. (The enteric nervous system (ENS) is now usually referred to as separate from the autonomic nervous system since it has its own independent reflex activity.)
Sympathetic tone synonyms, Sympathetic tone pronunciation, Sympathetic tone translation, English dictionary definition of Sympathetic tone. n. The part of the autonomic nervous system originating in the thoracic and lumbar regions of the spinal cord that in general inhibits or opposes the...
Sympathetic nervous system definition is - the part of the autonomic nervous system that contains chiefly adrenergic fibers and tends to depress secretion, decrease the tone and contractility of smooth muscle, and increase heart rate.
Vagal tone refers to activity of the vagus nerve, the 10th cranial nerve and a fundamental component of the parasympathetic branch of the autonomic nervous system. This branch of the nervous system is not under conscious control and is largely responsible for the regulation of several body compartments at rest.
What Happens When You Increase Parasympathetic Tone? Increasing stimulation of the parasympathetic nervous system decreases heart rate and blood pressure as well as the size of the pupil. At the same time, it increases digestion, urination, defecation and sexual arousal.
Parasympathetic tone reduces the spontaneous discharge rate of the sinus node, whereas its withdrawal accelerates sinus node automaticity. Acetylcholine, the principal neurotransmitter of the parasympathetic nervous system, inhibits spontaneous impulse generation in the sinus node by increasing K + conductance.