Term
| Parasympathetic characteristics |
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Definition
| Long presynaptic, short postsynaptic, ganglion near target organ, ganglion has nicotinic ACh receptor, target has muscarinic receptor. Also called "cholinergic system". |
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Term
| Sympathetic characteristics |
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Definition
| Short presynaptic, long postsynaptic, ganglion near spinal cord. Ganglion has nicotinic ACh receptor, target usually binds norepi on adrenergic receptor. Exceptions: adrenal medulla releases 80% epi and 20% norepi, sweat glands use ACh on a muscarinic receptor, and renal vasc. uses dopamine on dopamine receptors. Also called "adrenergic system". |
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Term
| Cholinergic signaling steps |
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Definition
| ACh made from choline and acetyl-CoA by choline acetyltransferase. Stored in vesicles, release is triggered by Ca influx. Rapidly degraded by acetylcholine esterase. |
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Term
| Adrenergic signaling steps |
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Definition
| Tyrosine -> DOPA -> dopamine -> norepinephrine. Dopamine is stored in vesicles where it is made into norepi. Release is triggered by Ca influx. Norepi is taken back up into presynaptic cell and diffuses away, although removal is not as fast as ACh. |
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Term
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Definition
Nicotinic: all ANS ganglia have them; ligand-gated ion channel. Two types: muscle and neuronal/ganglionic.
Muscarinic: Receptors on PNS target organs, GPCR. M(1,3,5) use IP3 and DAG; M(2,4) inhibit adenylyl cyclase. |
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Term
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Definition
| All are GPCRs, with several different second messenger systems. Alpha are more sensitive to epi/norepi that isoproterenol, while beta are more sensitive to isop. Alpha-1 are Gq, alpha-2 are Gi. Beta(1,2,3) are all Gs and activate adenylyl cyclase. |
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Term
| Alpha-1 receptor (5 locations) |
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Definition
Gq receptor, increases Ca concentration.
Vascular smooth muscle (splanchnic, skin)- contraction, increase BP.
Pupillary dilator muscle - contraction, mydriasis.
GI tract - relax wall.
GI/Bladder - contract sphincters.
Salivary glands - Increase secretion (transient, slight) |
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Term
| Alpha-2 receptor (2 locations) |
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Definition
Gi receptor, functions as autoreceptor by decreasing cAMP.
Presynaptic cell - decreases symphathetic outflow.
Pancreas - inhibits insulin release. |
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Term
| Beta-1 receptor (4 locations) |
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Definition
Gs, increases cAMP.
Heart - increase HR, force of contraction (FoC), and conduction velocity
Kidney - renin release (increase BP)
Eye - production of aqueous humor
Salivary glands - enhances amylase secretion
(Fat - increases lipolysis [not in notes, but in First Aid]) |
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Term
| Beta-2 receptor (5 locations) |
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Definition
Gs, increases cAMP.
Bronchi - relaxation
Blood vessel walls (skeletal muscle) - vasodilation
GI/Bladder walls - relaxation
Liver, skeletal muscle - gluconeogenesis and glycogenolysis
Pancreas - increase insulin secretion (slight)
(Fat - lipolysis [not in notes, but in First Aid]) |
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Term
| Beta-3 receptor (1 locations) |
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Definition
Gs, increases cAMP
Fat - lipolysis. |
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Term
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Definition
Gq receptor, IP3, DAG, calcium increase.
In CNS, enteric nervous system and autonomic ganglia. |
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Term
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Definition
Gi receptor, hyperpolarizes cell by increasing K conductance, affects the heart.
Heart - decrease HR and contractility. |
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Term
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Definition
Gq receptor, IP3, DAG, calcium increase, affects glands and smooth muscle.
Secretory glands - increase secretion (gastric acid, sweat, etc.)
GI tract - increases motility, relax sphincters
Bronchioles - bronchoconstriction
Bladder - contracts bladder wall, relaxes sphincter
Eye - constricts pupil (miosis), contracts ciliary muscle (accommodation) |
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Term
| ACh effect on blood vessels |
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Definition
| Endothelium has receptors (muscarinic) for ACh. When ACh binds nitric oxide is released, which diffuses to smooth muscle and causes vasodilation. Nitroglycerin and nitroprusside for angina take advantage of NO's role here. |
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