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17 Cards in this Set
- Front
- Back
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Synthesis of ACh?
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Acetate + Coenzyme A =AcCoA synthetase=> acetylCoA+choline=Choline transferase=>ACh
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Metabolism of ACh?
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ACh=acetylcholinesterase=>choline + acetate
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Focal innervated muscle fibers?
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Muscle fibers that receive innervation at a single endplate region e.g. mammalian fibers
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Multiply-innervated muscle fibers?
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Receive dense innervation e.g. amphibia and birds
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Low conc. of ACh at NMJ causes....
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muscular contraction
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High conc. of ACh at NMJ causes....
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inhibition of muscular contraction
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Non-depolarising NMJ blocking drugs? example, side effects, , MOA, revesilble
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MOA - block ACh, competative antagonists
Tubocuraine - cuases paralysis dosnt block nerve conduction or contractility side effects - hypotension, histimine release, respiratory failure reversered by increasing ACh (i.e. use AChEIs) |
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Depolarising NMJ blocking drugs? example, side effects, , MOA, revesilble
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MOA - weak agonists of ACh, causes maintained depolarisation (more slowly hydrolysed by cholineserase) and loss of electricable excitablity
Side - effects - transient twitching (fasciculations) example - suxamethonium |
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Gallamine?
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non-depolarising NMJ blocking drug
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Pancuorium?
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non-depolarising NMJ blocking drug
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Hexamethonium
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Depolarising ganglionic blocking drug
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decamethonium?
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Depolarising NMJ blocking drug
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Side effects of depolarising drugs? (4)
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1)Bradycardia
2)K releases=>heperkalemia=>ventricular dysrythmias 3)increases intra occular pressure 4)prolonged paralysis - in patients with cholineseterase deficiency, liver disease, taking anticholinesterase drugs |
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Suxa vs. tubocuranine effects in chicks?
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suxa - powerful extensor muscle spasm
tubocuraine - flacid paralysis |
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Uses of depolarising drugs?
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adjuct to general aneasthesia
emergency intubation c-section lethal injection |
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How to overcome depolarising blockers?
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mutual antagonism - tubocarine (non-depo) reduces depolarisation, brings membrane potential closer to threshold
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How to overcome non-depolarising blockers?
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AChEIs - increase ACh in synaptic cleft (may worsen depolarisng blockers)
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