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Parasympathetic
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∙ 12y ago
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What do Cholinergic fibers secrete?
Acetylcholine (Ach), which causes sweat production
What are norepinephrine releasing fibers called?
Andrenergic fibers release Norepinephrine and Cholinergic fibers release Acetylcholine.
What secretes norepinephrine adrenergic fibers?
sympathetic division. Parasympathetic division fibers called cholinergic fibers release acetylcholine.
Which division of the autonomic nervous system secretes acetylcholine via cholinergic nerve fibers?
Parasympathetic nervous system .
Does the sympathetic division secrete norepinephrine?
Yes, when stimulated the sympathetic postganglionic fibers release norepinepherine (20%) and epinepherine (80%).
Impulses carried to the heart by means of fibers that secrete acetylcholine are what?
parasympathetic impulses and cause the heart rate to decrease
Why does acetylcholine causes vaso-dilation?
In some muscle tissue acetylcholine causes vaso-dilation, but not all. Norepinephrine is the opposite competor/effector of acetylcholine. Acetylcholine is present in all preganglionic fibers, both parasympathetic and sympathetic. Acetylcholine is present in postganglionic parasympatic fibers, where norepinephrine is present in the postganglionic sympathetic fibers. In some tissues acetylcholine causes constriction. Can also reduce heart rate vi the vagus nerve. Acetylcholine is the only neurotransmitter used in the somatic nervous system! Acetylcholine can effect vasodilation by several mechanisms, including activation of endothelial nitric oxide (NO) synthase and prostaglandin (PG) production. In human skin, exogenous Acetylcholine increases both skin blood flow and bioavailable NO levels, but the relative increase is much greater in skin blood flow than NO. So this may lead us to speculate that acetylcholine may dilate cutaneous blood vessels through PGs, as well as NO. In some muscle tissue acetylcholine causes vaso-dilation, but not all. Norepinephrine is the opposite competor/effector of acetylcholine. Acetylcholine is present in all preganglionic fibers, both parasympathetic and sympathetic. Acetylcholine is present in postganglionic parasympatic fibers, where norepinephrine is present in the postganglionic sympathetic fibers. In some tissues acetylcholine causes constriction. Can also reduce heart rate vi the vagus nerve. Acetylcholine is the only neurotransmitter used in the somatic nervous system! Acetylcholine can effect vasodilation by several mechanisms, including activation of endothelial nitric oxide (NO) synthase and prostaglandin (PG) production. In human skin, exogenous Acetylcholine increases both skin blood flow and bioavailable NO levels, but the relative increase is much greater in skin blood flow than NO. So this may lead us to speculate that acetylcholine may dilate cutaneous blood vessels through PGs, as well as NO.
What stimulates the adrenal medulla to secrete its excitatory hormones?
preganglionic sympathetic fibers releasing acetylcholine that bind to receptors on the adrenal medulla
How would a drug that stimulates acetylcholine receptors affect the sympathetic nervous system?
Preganglionic fibers for the SNS release ACh; so a drug that stimulates ACh receptors would stimulate the postganglionic fibers of sypathetic nerves, resulting in increased sympathetic activity
What has short unmyelinated postganglionic fibers?
parasynpathetic system
Which division of the autonomic nervous system is characterized by short preganglionic and long postganglionic fibers?
The parasympathetic nervous system has long preganglionic and short postganglionic fibers
What releases catecholamines as a neurotransmitter?
it would be postganglionic sympathetic fibers
