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Unformatted text preview: membrane of postsynaptic where receptors are) is very
wide. there's no synapse and there's no specialized structure. the neurotransmitters have to diffuse considerable distance in order to reach target organ.
all these put together (the small, unmyelinated axon, neurotransmitter have to diffuse through long distance) means this system is not a rapid, active
system, rather changes caused by postsynaptic cell ANS will develop slowly but more long lasting. Postganglionic Sympathetic Synapses
the neurotransmitter being release by presynap is noraepinerine. bottom is target cell.
epinephrine accumulate because postgang lack enzyme to convert norepineph to epinephrine.
which neurotransmitter relesase depend on enzyme. they bind to adrenergic receptor (G-Protein
coupled). you have vesicles of neurotransmitter, v-gated ca cause release of vesicles. the
synaptic cleft can be substantial. this is halfway synaptic and paracrine. neurotransmitter is
breakdown through binding of COMT, recycle back to cleft (broke down by monoamine
oxidase). MAO inhibitor prolong existence of norepinephrine in existing tissue. *
*monoamine oxidase COMT* *catecholamine-Omethyltransferase tyrosine DOPA dopamine norepinephrine Catecholamines epinephrine Autonomic
2. prevertebral ganglia is located at the abdomen. red and blue dot=...
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- Spring '09