NEET2004ZoologyNeural Control and CoordinationActual
Unidirectional transmission of a nerve impulse through nerve fibre is due to the fact that
Options
- Anerve fibre is insulated by a medullary sheath
- Bsodium pump starts operating only at the cyton and then continues into the nerve fibre
- Cneurotransmitters are released by dendrites and not by axon endings
- Dneurotransmitters are released by the axon endings and not by dendrites.
Correct answer
D. neurotransmitters are released by the axon endings and not by dendrites.
Step-by-step solution
A synapse occurs where the axon of one neuron (the pre-synaptic neuron) meets either the dendrite or the cell body of another (the post-synaptic neuron). At the tip of the pre-synaptic axon is a button shaped swelling called a synaptic knob, inside which are numerous mitochondria and vesicles packed with a substance called a neurotransmitter is present. This neurotransmitters at the time of nerve impulse diffuse across the space and bind to receptors in the membrane of the post-synaptic cell. This opens ion channel