Question

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

• A. Neurotransmitters are naturally attracted towards the brain.
• B. Neurotransmitters are released by the axon endings and not by dendrites.
• C. Neurotransmitters are released by dendrites and not by axon endings.
• D. A nerve fibre is insulated by myelin sheath which ensures unidirectional flow.

Answer 1

The correct option is B

Neurotransmitters are released by the axon endings and not by dendrites.

A nerve is a set of neurons. Each neuron release chemicals into the synaptic cleft to stimulate the next neuron. The chemicals are stored and released at only one end of the neuron, i.e, at the ends of the axons. Hence, transmission is in one direction for each neuron- denrtites to axons to dentrites of the next neuron.