Question

Unidirectional transmission of a nerve impulse through nerve fiber is due to the fact that:

• (A) Nerve fibre is insulated by a medullary sheath
• (B) The sodium pump starts operating only at the cyton and then continues into the nerve fiber
• (C) Neurotransmitters are released by dendrites and not by axon endings
• (D) Neurotransmitters are released by the axon endings and not by dendrites

Answer 1

The Correct Option is D

Explanation:
Unidirectional transmission of a nerve impulse through nerve fiber is due to the fact that neurotransmitters are released by the axon endings and not by dendrites.Transmission of nerve impulses through nerve fiber occurs unidirectionally because the axon of one neuron is linked to the dendrite of another neuron through the synapse. Synaptic vesicles are filled with a neurotransmitter (e.g., Acetylcholine) released by axone endings, not by dendrites.Hence, the correct option is (D).