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Do the post-ganglionic sympathetic fibers release acetylcholine?
Wiki User
∙ 8y ago
No, post-ganglionic sympathetic fibers mostly release norepinephrine.
But they do release some ACh to the sweat glands, which causes concurrent vasodilation of surrounding blood vessels (paired with release of bradykinin from sweat glands).
Wiki User
∙ 8y ago
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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
Postganglionic axons secrete acetylcholine cholinergic fibers?
Parasympathetic
Does the sympathetic division secrete norepinephrine?
Yes, when stimulated the sympathetic postganglionic fibers release norepinepherine (20%) and epinepherine (80%).
What secretes norepinephrine adrenergic fibers?
sympathetic division. Parasympathetic division fibers called cholinergic fibers release acetylcholine.
What releases catecholamines as a neurotransmitter?
it would be postganglionic sympathetic fibers
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.
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 are norepinephrine releasing fibers called?
Andrenergic fibers release Norepinephrine and Cholinergic fibers release Acetylcholine.
Postganglionic fibers that innervate targets in the body wall or thoracic cavity originate on neurons within?
sympathetic chain ganglia
Is acetylcholine the substance released by axonal endings of the somatic efferent fibers and by the parasympathetic nerve fiber endings?
Yes, it does. In contrast, the sympathetic nerves release adrenaline
Do all visceral motor neurons synapse in a sympathetic ganglion?
No; some axons synapse in nearby autonomic ganglion. postganglionic fibers travel along either sympathetic nerves or rejoin at the spinal nerve.
What stimulates the adrenal medulla to secrete its excitatory hormones?
preganglionic sympathetic fibers releasing acetylcholine that bind to receptors on the adrenal medulla
