Question

Unidirectional transmission of impulse through a chemical synapse is due to?

• A. Release of neurotransmitters by axon and not by dendrites.
• B. Release of neurotransmitters by dendrites and not by axon.
• C. Insulation of axon by myelin sheath.
• D. Secretion of myelin by Schwann cells.

Answer 1

Answer: (A)

The main reason for unidirectional transmission of impulse through chemical synapse is the release of neurotransmitters at the synaptic cleft. The telodendrons release the neurotransmitters like acetylcholine. These are present at the ends of the axon. The dendrites of the nerve cells do not secrete these transmitters. The dendrites of the other neuron have receptors on their surface to bind these neurotransmitters. This causes the movement of impulse in one direction from the axon of one neuron to the dendrites of the other neuron.