ANP1105Topic 2 - Part 4 Fall 2020.pdf - ANP1105B Anatomy &...

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ANP1105BAnatomy & Physiology ITopic 2. Part 4Cellular Physiology of Nerve and Muscle
Synaptic Delay:·Synaptic communication is theslowest (rate-limiting) step ofneurotransmission -Why??time required for NT release,diffusion across synaptic cleft &binding to postsynapticreceptor: 0.3-5 ms2.2.4.3define synapticdelay2.2.4.4distinguish between EPSPs and IPSPs in terms of channelsopened and end results in terms of membrane potential/ease ofgenerating an action potentialPostsynaptic Potentials –these are in the dendritic region!channels respond tochemicalsrather than changes in membrane potentialchannels mediate local changes in membrane potential:gradedaccordingto the amount of NT (= number of channels opened)-2-summary-of-events-in-chemical-synaptic-transmission-at-the-neuromuscular-synapse-diagram/becauseittakestimeexitatowtinhipatomt
2 types of PSPs:(i)excitatory postsynaptic potentials (EPSPs)(ii)inhibitory postsynaptic potentials (IPSPs)From Focus Fig. 11.4
EPSPs:NT bindingmembrane depolarization; opensonechannel forbothNa+ & K+electrochemical gradient for Na+steeperthan for K+;What is end result??What is generated is NOT an AP; only axonalmembranes can generateAPs!!; get local, graded depolarizations called EPSPs; if strong enough toreach axon hillock, then get APFrom FocusFig. 11.4IPSPs:NT binding leads to membrane hyperpolarization by increasingpermeability to K+orCl-What is the end result in terms of membrane potential?What is end result in terms of ease of generating an AP?conletrationgradientgoingtocomeevenmorenegativewillbecomeevenharder,needstrongerpositive
2.2.4.5define (in terms of EPSPs & IPSPs): temporal summation, spatialsummation; justify the role of the axon hillock as the neural integratorC1.Summation by Postsynaptic NeuronAsingleEPSPcannotgenerate an AP2 types of summation (EPSPs&IPSPs):(i)temporal:(ii)spatial:axon hillock =neural integrator(numerous EPSPs & IPSPs)mosteffectivesynapses are closest to the axon hillock –why??

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Term
Spring
Professor
RHODES
Tags
muscles

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