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25 Cards in this Set
- Front
- Back
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sympathetic nervous system |
1. regulates activity of tissues with a diffuse distribution (sweat glands, smooth muscles of blood vessels and hair follicles) -->NO PARASYMPATHETIC INNERVATION |
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sympathetic nervous system |
fight or flight -adrenal medulla Increased HR, relaxation of airways, inhibited digestion, increased metabolism |
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parasympathetic NS |
discrete and selectively directed at individual organs -excitatory effect on GI tract, slow HR, voiding bladder (micturition) |
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Glands |
parasympathetic always stims glandular secretions. sympathetic stims sweat glands and has minor effects on salivary secretions and some digestion glands |
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metabolic effects |
are only mediated by sympathetic and adrenal medulla |
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released NE is inactivated by reuptake in the postganglionic sympathetic nerve varicosities |
NE is transported back via a sodium-dependent membrane pump (2nd messenger) |
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receptors function as a coding system |
very high specificity (NE wont bind to ACH receptor) |
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The ANS can produce EXCITATORY AND INHIBITORY responses depending on the tissue innervated |
somatic motor innervation of skeletal muscle where the response is EXCITATORY (contraction) |
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receptors on postganglionic neurons are excited by ____________ |
NICOTINE. These are called cholinergic receptors of the NICOTINIC type (nicotine receptors) |
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Action potentials in preganglion always generation an AP in the postganglion |
NA and K pass down electrochemical gradient and neuron is depolarized |
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unlike skeletal muscles, nicotinic receptors can be blocked by _________ |
hexamethonium (also other ganglionic blockers) that dont effect skeletal NMJ |
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parasympathetic neuroeffector junctino ACH is excitatory in the ______________ and inhibitory in the _____________ |
smooth muscle and glands, heart. (muscarinic receptors) |
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2 types of muscarinic receptors |
inhibitory (heart) excitatory (smooth muscle and glands) |
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Muscarinic in the heart |
coupled via G-Protein to a K channel that is opened in the presence of ACH and slows the rate of depolarization |
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Muscarinic in smooth muscle and glands |
muscarinic receptor is coupled with phospholipase C. ACH stimulates IP3, which releases Ca++ causing constriction or secretion |
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muscarinic receptors are present on the generalized sweat glands which receive a cholinergic ____________ innervation |
sympathetic |
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muscarine poisoning- SLUDGE |
Salivation: stimulation of the salivary glands Lacrimation: stimulation of the lacrimal glands Urination: relaxation of the internal sphincter muscle of urethra, and contraction of the detrusor muscles Diaphoresis Gastrointestinal upset: Smooth muscle tone changes causing gastrointestinal problems, including diarrhea Emesis: Vomiting |
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muscarinic receptors are blocked by |
Atropine (muscarinic antagonist) -blocks the effects of ongoing activation of muscarinic receptors -reverses muscarine poisioning |
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atropine |
inhibition of glandular secretions (dry stuff) tachycardia loss of the pupillary light reflex loss of ability to focus close up (cycloplegia) mydriasis |
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Alpha1 receptors |
smooth muscles excitiation - EPI and NE EPI never gets high enough to be effective NE-->IP3--> Ca++ release from SR = contraction |
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Alpha2 receptors |
inhibitory. not oneffector organ, its on nerve terminals. Inhibit transmitter release. Presynaptic inhibition. *sit onparasympathetic nerve terminals which innervate the GI Tract, inhibits GI.* Reduces the release of ACH from action potentials. |
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Beta1 |
excitiation verysensitive to catecholamines. Epi and NE. Located in heart effective in lower [conc] than alpha1 |
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Beta2 |
relaxation/inhibition of smooth muscle. founded on bronchial smooth muscle, GI tract, smooth muscle of blood vessels (BV occur along with alpha1) EPI is more potent than NE (almost ineffective) Beta receptors are more sensitive to EPI than Alpha |
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metabolic effects of NE and EPI are mediated by both ________ and _______ receptors |
alpha, beta |
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B1 and B2 receptors are coupled to_______ |
adenylate cyclase, thus generate cAMP with subsequent activation of protein kinase A and phosphorylation of proteins |
