Nerve Impulse

• A nerve impulse, also known as an action potential, is an electrical signal that travels along the nerve cells or neurons in the nervous system.
• It is the fundamental mechanism through which neurons communicate with each other and transmit information.
• Nerve impulses are crucial for processing sensory input, generating motor output, and enabling higher cognitive functions such as learning and memory.

Here’s an overview of how a nerve impulse is generated and transmitted:

1. Resting state:

• Neuron at resting membrane potential, around -70 mV.

2. Stimulus and depolarization:

• External stimulus cause local depolarization; if threshold is reached, voltage-gated Na+ channels open, leading to a rapid increase in membrane potential.

3. Propagation:

• Nerve impulse travels along the axon as depolarization opens voltage-gated Na+ channels in adjacent regions.

4. Repolarization:

• Voltage-gated K+ channels open, allowing K+ ions to exit, restoring membrane potential back to resting state.

5. Refractory period:

• Neuron enters a period where generating another action potential is difficult or impossible, ensuring unidirectional propagation of nerve impulses.

6. Synaptic transmission:

• It triggers neurotransmitter release at the synaptic terminal, influencing the postsynaptic neuron’s membrane potential.

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