Question

Identify the phases of an action potential. +30 Answer Bank undershoot repolarization phase depolarization phase Membrane potential (mV) Resting potential Threshold potential - - - - - - - - - - Time (ms)

Answer 1

Ans: Resting potential (Potential across the membrane) is around -60 to -70 mV. This means that the internal environment of the cell is negative relative to the outside of the cell.

Both Na* As channels closed open Na* channels close Kº channels open Nat channels reset channels remain open Both channels closed K Na*/K channels AUTOHARAREHE High High Increasing Excitability Zero Absolute refractory period Relative refractory period -Action potential Membrane potential (mv) Na lon permeability Time (milliseconds)

Hyperpolarization (undershoot) occurs when the membrane potential become relatively more negative at a perticular spot on the neuron's membrane, while depolarisation occurs when the membrane potential is relatively less nagative ( more positive) due to the transport of Na⁺ ions through the Na⁺ ion channels, and repolarization occurs just after the depolarization K⁺ ion channels opened and Na⁺ ion channels get closed as result K⁺ ions move out from cell and the membrane potential falls down.

V-gated K+ channels begin to open V-gated Nat channels begin to close V gated Na closed V-gated Kt open K+ rushes out +30 Depolarization Repolarization Membrane potential (mV) Another graded potential reaches threshold V-gated Nat channels open Nat rushes in V-gated K+ channels closing and the rush of K+ out slows down Stimulus causes graded potential and ligand gated cation channels open - - - - - - - - - - - - - - - - - - - - All V gated K Closed - - - - - - - - - - - - - - Hyperpolarization All K+ leak channels open and some V-gated K+ channels still open

So now the answer of your question is;

+30 Answer Bank undershoot Depolarization Repolarization repolarization phase depolarization phase Membrane potential (mV) Resting potential Threshold potential Undershoot... Time (ms)

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