Question

How do neurons communicate with other cells?

Answer 1

Hint: Whenever a stimulus reaches a neuron, an action potential is generated. An action potential is a brief (approx. 1ms) electrical signal that generates in the axon of a neuron and marks it as active. This electrical signal propagates along the axon length and causes neurotransmitter activity.

Complete answer:
Neuron communicates with cells by communicating with other neurons. A continuous conversion between the electrical signal and chemical signal propagates the nerve impulse across the body.

The electrical gradient across the cell membrane is not static, it is constantly changing. The resting membrane potential of a cell is -70 mV. This membrane potential upon the influence of axon stimulation goes up and down causing an electrical signal to generate and propagate. This is called an action potential. Action potentials are the basic units of communication between neurons.

When an action potential reaches the end of an axon, the electrical signal converts to a chemical signal to propagate the nerve impulse. This happens across synapses. When an axon potential reaches a synapse, i.e. presynaptic terminal, chemicals released from the channels called a neurotransmitter. This neurotransmitter gets released between the presynaptic axon terminal and postsynaptic dendrite, known as the synaptic cleft.

The neurotransmitter crosses the synaptic cleft and attaches to the neurotransmitter receptor on the postsynaptic side, and again converts the chemical signal into an electrical signal and continues to propagate nerve impulses. This is how neurons communicate with other cells.

Note: As we know that the normal resting membrane potential is -70mV. But when positive ion $(Na^+, K^+, Ca^+)$ or negative ion $(Cl^+)$ travels through synapses it alters the membrane potential. When the sum of all excitatory and inhibitory input makes the membrane potential around -50mV, action potential generates, and this threshold value is called action potential threshold.