Explain the mechanism of generation and conduction of nerve impulse. please

Ion channels are present in neural membrane which is selectively permeable to different ions. When neuron is not conducting impulse (resting), axonal membrane is more permeable to K+ ions and impermeable to Na+ ions. Ionic gradient across the resting membrane is maintained by active transport of ions by sodium-potassium pump. This will develop positive charge outside the axonal membrane and negative charge on inner side. 
The electrical potential difference across the resting membrane is called resting potential. When stimulus is applied at site A, the membrane becomes permeable to Na+ ions to make rapid influx of Na+ ions to create outer surface negatively charged and inner membrane positively charged that create Action Potential or nerve impulse. The nerve impulse from A moves to B in inner surface and B to A on outer surface. This process is repeated several times to transmit the impulse. Nerve impulse is transmitted from one neuron to another neuron through synapse. There are two types of synapse-

1. Electrical synapse- the membrane of pre and post synaptic neuron is very close to each other and current flow directly from one neuron to another. 2. Chemical synapse- pre and post synaptic neuron is separated by fluid filled space called synaptic cleft. Neurotransmitters are involved in transmission of impulses.

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