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36 Cards in this Set
- Front
- Back
- 3rd side (hint)
What are the 2 systems which form the ANS?
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Sympathetic and parasympathetic nervous system
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Do skeletal muscles have pre/post ganglionic neurons?
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No - they just have one somatic motor neuron
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What are the effects of the innervation of the parasympathetic nervous system? Which receptor mediates these effects?
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DUMBELS - Diarrhea/diaphoresis (sweating), urination, miosis, bradychardia, bronchospasm, bronchorea, emesis, lacrimation, salivation. mAchr (muscarinic receptors)
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Name some catecholamines
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Tyrosine --> DOPA --> DA --> NA -->A
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Describe a nAchR, and its agonists
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Cation channel, nicotine and Ach. It has 4 transmembrane domains
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What are the agonists of a mAchR?
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Ach, muscarine and carbachol
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Describe mAchr
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GPCR, there are 5 types M1 - M5
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Name antagonists of the mAchr
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Atropine
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Describe the parasympathetic nervous system and what NTs are involved
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pre ganglionic neuron scretes Ach (nAchR) --> acts on postganglionic neuron which secretes nAch (mAchR)
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Describe the sympathetic nervous system and what NTs are involved
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pre ganglionic neuron scretes Ach (nAchR) --> acts on postganglionic neuron which secretes NA (adrenergic receptors)
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What NT acts on skeletal muscles?
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Ach on nAchRs
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What is an exception to the sympathetic nervous system?
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Sweat gland, the postganglionic neuron secretes Ach onto mAchR
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What happens to the blood vessels in the skin and viscera when sympathetic nervous system is stimulated?
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Blood vessels contract
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What happens to the blood vessels in skeletal muscles when sympathetic nervous system is stimulated?
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Dilate
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Describe what happens in terms of the innervation of the adrenal medulla in the sypathetic nervous system
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Preganglionic neuron passes through the ganglionic chain without synapsing into adrenal medulla onto chromaffin cells. These cells release NA and A into blood
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What is BP conrolled by?
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Resistance in arteries and heart rate
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What is the baroreceptor reflex?
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The process which occurs to bring down BP when too high and vice versa
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Where are baroreceptors located?
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In carotid sinus
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How does the baroreceptor reflex work?
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Baroreceptor is stimulated by stretch/high BP. If BP too high parasympathetic NS is stimulated (to decrease HR) and sympathetic stimulation is reduced and vice versa
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What do Achesterases do?
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Break down Ach and increase contractions
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How does botox work?
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Prevents the release of Ach and other NTs--> paralysis
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What is depolarisation block?
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Where nAchR is continuously activated resulting in decreased electrical excitability
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What are the effects of high dose Achesterase inhibitor on muscarinic receptors?
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blurred vision, lacrimation, emesis, bradychardia
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What are the effects of high dose Achesterase inhibitor on nicotinic receptors?
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Depolarisation block leading to flaccid paralysis
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What are the effects of atropine?
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Mydriasis, tachycardia, blurred vision, constipation, dry mouth
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Uses of atropine
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Asthma (bronchodilation), in surgery to inhibit vagus reflex (bronchospasm and bradychardia)
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Use of scopolamine
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anti-emetic
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What are the different types of nAchRs?
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muscles, ganglionic and CNS --> all structurally different
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Effects of Nicotine
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(MTWThF) - Mydriasis, tachycardia, weakness, hyperthermia, fasciculation
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What are the effects of ganglionic blockers on the sympathetic NS?
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Vasodilation in skin and viscera which decreases BP
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What are the effects of ganglionic blockers on the parasympathetic NS?
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Heart rate increases
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Side effect of ganglionic blocking drugs?
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Orthostatic hypotension (as it blocks most cardiovascular reflexes)
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What is the problem with old muscle relaxants?
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Blocks nAchRs at ganglions and adrenal medulla causing decrease in BP and tachcardia
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Modern muscle relaxants only work peripherally at nAchR
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Describe the non-depolarising action of muscle relaxants
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Use of Ach antagonist
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Describe the depolarising action of muscle-relaxants
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use of nAchR agonist which causes depolarisation block and then flaccid paralysis
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Why are muscle relaxants used?
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Easier to cut relaxed muscles, less damage done
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