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Physiology

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Nerve Muscle Physiology

Question
15 out of 24
 

EPSP is due to(DNB Dec-2012)



A K+ influx
B Na+ efflux

C Na+ influx
D Ca++ influx

Ans. C Na+ influx
  1. EPSP (Excitatory post synaptic potential) -

i. Definition: the increase in voltage above the normal resting potential — that is to a less negative value — is called EPSP because if this potential rises high enough, it will elicit on action potential in the neuron, thus exciting it.

ii. EPSP is due to depolarization Q.

iii. Production rapid influx of Na+ to the interior neutralised part of the negativity of RMP RMP ed from - 65 to 55 EPSP excite the neuron.

[Note by openings of Na+ or Ca++ ions channels, producing an inward current].

  1. IPSP (Inhibitory post synaptic potential)

i. Definition increase in negativity beyond the RMP level is called IPSP, that inhibits the neuron to be excited. Q

ii. Production - opening of the chloride channels will allows negatively charged chloride ions to move to the interior

CT ions influx) membrane potential becomes more negative than normal; and opening of K+ channels will have K+ ions to move to the exterior (K+ ion efflux). make membrane potential more negative than usual. Thus Cl- influx and K+ efflux increase the degree of intracellular negativity called Hyperpolarization Q inhibits the neuron to be excited.

[ Note — In addition IPSP is also produced by K+ eflux and clossure of the Na+ or Ca++ channels]

Nerve Muscle Physiology Flashcard List

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