Question

Distinguish between:
Impulse conduction in a myelinated nerve fiber and non- myelinated nerve fiber.

Answer 1

The signal that travels along the length of a nerve fiber and ends in the release of neurotransmitters.
Nerve impulses are the means by which information is transmitted along the neuron and throughout the nervous system.

Complete answer:
Neurons are the specialized cells found in the neural system of all animals.
Structure of neuron consists of:
1. Dendrites
2. Nissl’s granules
3. Cell body
4. Nucleus
5. Axon
6. Myelin sheath
7. Node of ranvier
8. Axon terminal
9. Synaptic Knob
Myelinated nerve fibre: The nerves that are insulated by a sheath of myelin are called myelinated nerve fibres.
Non- myelinated nerve fibre: The nerves which lack such sheath are called non-myelinated nerve fibres.

Myelinated nerve fibre	Non-myelinated nerve fibre
1. It contain myelin sheath	1. It lacks myelin sheath.
2. It is white in colour	2. It is grey in colour
3. It consists of node of ranvier	3. It do not contain node of ranvier
4. Speed of transmission is high because impulse transferred by myelin sheath without obstruction.	4. Speed of transmission is low because it lacks myelin sheath
5. It includes peripheral nerves	5. It includes post sympathetic and small axon nerves.
6. Long axons nerve fibres are myelinated	6. Short axon nerve fibres are unmyelinated.
7. Myelin sheath prevents the loss of impulse	7. Due to the absence of myelin sheath, loss of impulses takes place.

Note: Some of the characteristic features of impulse are:
1. Electrical excitability
2. Uniform conduction rate
3. All or none response
4. Absolute refractoriness
Impulse is transmitted from one neuron to another neuron with the help of a junction known as synapse.