Why is the movement of nerve impulses unidirectional? Elaborate.

AcademicBiologyNCERTClass 10

The nerve impulse is an electrical phenomenon through which nerve cells (neurons) communicate with each other. It is generated due to the difference in electric potential between two ends of the nerve region.

The axon of one neuron communicates with the dendron of another neuron via a synapse to convey the nerve impulses produced on an axonal hillock in response to a stimulus.

The neurotransmitters like acetylcholine are released by the telodendrons, which are present at the ends of the axon; these neurotransmitters are not secreted by the smaller extensions called the dendrites. This results in the movement of the impulse in one direction from the axon of one neuron to the dendron of the other neuron.

The nerve impulse in our body travels in the form of electrical impulses.

  • The information acquired at the dendrites of the neuron sets off a chemical reaction that helps to create an electric impulse.
  • This impulse collected through dendrites travels from the cyton along the axon and reaches the nerve endings.

[Extra information:

When a stimulus acts on the receptor (it stays in touch with the dendrites of the sensory neuron), a chemical reaction is initiated that produces an electrical impulse in the receptor. This electrical impulse travels from the dendrites of the sensory neuron (say A) to its cell body and, then, along its axon. 

When the electrical impulse reaches the end of the axon of the sensory neuron, the electrical impulse releases chemical substances called neurotransmitters in a very small amount into the synapse between two adjacent neurons.

The neurotransmitter crosses the synapse and starts a similar electrical impulse in the dendrite of the next neuron.

In this way, the electrical impulse passes from one neuron to the next across the synapse.]

Updated on 10-Oct-2022 13:46:41