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ANS Receptors nmc
receptors location effects review
Question | Answer |
---|---|
Synapses between neurons are made in the? | Autonomic ganglia |
PNS ganglia are located? | Effector organs |
SNS ganglia are located? | Paravertebral chains |
Preganglionic neurons have their cell bodies? | In the CNS and synapse in autonomic ganglia |
Postganglionic neurons have their cell bodies? | autonomic ganglia and synapse on effector organs (heart, bld vessels, sweat glands) |
Adrenal medulla preganglionic synapse? | Directly on chromaffin cells= Ach release= secrete 80% epinephrine, 20% norepinephrine. Differ from SNS bc epinephrine is release vs SNS release norepin only |
Difference between b1 and b2 receptor androgen affinities? | b1-adrenoceptors demonstrated equal affinity for adrenaline and nor- adrenaline while b2-adrenoceptors displayed a higher selectivity for nor-adrenaline than for adrenaline. |
a1 - location, function, mechanism of action? | Local: sm m.vasc (=NT release) and non- vasc (not bronchial); mostly Post synaptic (CNS and periph) Function: post-syn=CNS= excite; & peripherally= m. contraction-only norepin high enough conc Mech of action: Gp-formation of IP3 & intracell Ca incr |
a1- agonists and antagonists | a1 Agonists potency: epinep > norepin >> isoproterenol;A=NA>>ISO Phenylephrine (neosyn), Oxymetazoline Antagonists: antihypertensives-indoramin and prazosin, benign prostatic hypertrophy |
a2- location, function, mechanism of action? | Local: platelets, fat cells, smooth m.; mostly Pre- synaptic (CNS and periph) Function: pre-syn=inhibition (nor-adren= neg feedback);post-syn= bld ves constriction, platelet aggreg Mech of action: Gp-inhib of & decr cAMP= Decr Ca influx= decr NT |
a2- agonists and antagonists | a2 Agonists potency:A=NA>>ISO; antihypertensives- Clonidine Antagonists: Yohimbine, Idazoxan |
Name the a2 subtypes and their functions. | a2A,a2B and a2C a2- usually found presynaptically & inhibit the norepin = neg fdbk control of norepin. Postsynaptic a2 - liver cells, platelets, and the smooth muscle of blood vessels= platelet aggregation, and blood vessel constriction. |
How can a antagonist and agonists be used to treat hypertension? | a1-antagonists a2- agonists |
B1- location, function, mechanism of action? | Local: Post syn main: hrt, pltlets, saliv and non-sphict GI Function: excitation, sensitive to norep and epineph, > senst than alpha. Incr hrt rt/frc, relax non-sph GI, platelet aggrg, amylase secretion; Pre-syn=NT release Mech action: Gp, incr prod cA |
B1- agonists and antagonists? | B1 agonists: Norepineph, Isoproterenol, dobutamine, ISO>A=NA Antagonists: Propranolol, metoprolol |
B2- agonists and antagonists? | B2 agonists: Isoproterenol,albuterol Antagonists; ISO>A=NA Propranolol, Butoxamine |
B2- location, function, mechanism of action? | Local:Post syn-vasc and bronch sm m., GI Function: Relaxation= vaso- and broncho, inhib hist rls,rlx GI - more sent to epin vs norep and a rcpt E.g:small adrenal epin rls=B2 vasodil, vs large rls= a-vasoconst Mech action: Gp, incr prod cAMP |
B3- location, function, mechanism of action? | b3-receptors are expressed predominately in adipose tissue activation is proposed to be involved with noradrenaline induced changes in energy metabolism via lipolysis and thermogenesis. Mech action: Gp, incr prod cAMP |
B4- location, function, mechanism of action? | b4-receptors are localised in cardiac tissue with activation causing an increase in heart rate and force. Mech action: Gp, incr prod cAMP |
B4- agonists and antagonists? | B4 agonists: none antagonists: Bupranolol |
Cholinergic receptors | Refers to responses in various systems to the natural transmitter molecule Acetycholine (ACh). |
What are nicotine and muscarinic receptors? | Nicotine comes from tobacco, Muscarine comes from certain mushrooms. Named for the extrinsic compounds that stimulate only that category |
Summarize the function of Nicotinic recpts. | * Stimulated by ACh and nicotine, not stimulated by muscarn. * Found all ganglionic synapses & NM junctions. - Blocked by hexamethonium. |
Summarize the function of Nicotinic recpts. | Physio rsps to stim & block complex bc SNS and PNS affected. Final response = system w/ stronger tonic infl. Eg-heart- usually > PNS, but ganglionic block affect PNS more = hrt rt incr |
Summarize the function of Muscarinic recpts.-Mainly PNS | Stim by ACh and muscarine, not stimulated by nicotine. * Found at target organs when ACh is released by post-ganglionic neurons (all of PNS, some SNS). * Stimulated selectively by Muscarine, Bethanechol. * Blocked by Atropine. |
Muscarinic stimulation effects? | * Incr sweating. * Decr HR. * Decr BP bc decr CO. * Bronchoconstriction and increased bronchosecretion. * Pupil contract, * Tearing and salivation. * Incr motil and secr GI . * Urination and defecation. * Engorgement of genitalia. |
NMJ- ach, nicotine and muscarine effects? | NMJ = nicotinic recpt Ach= large response Nicotine=large response Muscarine= no response |
ANS ganglionice transmission- stimulation? | ANS ganglion = nicotinic recpt Ach= large response Nicotine=large response Muscarine= no response |
Lung Bronchiols-constriction | Lung bronchiols= Muscarinic rcpt Ach= large response Nicotine=No response Muscarine= Large response |
Nicotinic recpts- location, function, mechanism of action? | Local: autonomic gang & NMJ Function: excitation Mech action: Activated by Ach or nicotine, Ach recpt are Na and K ion channels |
Muscarinic recpts- location, function, mechanism of action? | Local: heart, non-vasc smooth m and glands Function: inhib heart and excite sm. m. Mech action: Activated by Ach or muscarine; Atropine Blocks. Heart SA (M2)- inhib cAmp path and K ch= slower depol Sm m.& glands (M3)- form IP3 and incr Ca |
Heart- Name SNS action & recepts and PNS action | Heart SNS: incr HR, contract Recpts: B1 PNS: decr HR, contract |
Vascular Smooth- Name SNS action & recepts and PNS action | Vascular sm. m SNS:constrict bld vessels in skin, splanchnic (a); Dilates bld ves skeletal (b2) PNS: |
GI tract- Name SNS action & recepts and PNS action | GI tract SNS:decr motility (a2, b2), constricts sphincters(a1) PNS: incr motility (a2,b2); relax sphincters |
Bronchioles- Name SNS action & recepts and PNS action | Bronchioles- SNS:Dilates sm m. (B2) PNS: Constricts sm m. |
Male sex organs- Name SNS action & recepts and PNS action | Male sex organs- SNS: Ejaculation (a) PNS: Erection |
Bladder- Name SNS action & recepts and PNS action | Bladder- SNS: Relaxes bladder wall (b2), constricts sphincter (a1) PNS: contracts wall, & relax sphincter |
Sweat glands- Name cholinergic action & recepts and PNS action | Sweat glands- SNS: Increase sweating (M3) PNS: |
Kidney- Name SNS action & recepts and PNS action | Kidney- SNS: incr Renin secretion (B1) PNS: |
Fat cells- Name SNS action & recepts and PNS action | Fat cells SNS: incr lipolysis (b1), decr lipolysis (a2) |