Question

Which of the following is regarded as a unit of nervous tissue?

(a) neurons

(b) myelin sheath

(c) axons

(d) dendrites.

Answer 1

(a) neurons

A neuron is the functional unit of the nervous system. A typical neuron consists of three processes namely,

1. Dendrite
2. Nerve cell or cell body
3. Axon

Dendrites are the short fibers arising from the body of the nerve cell. They act as receptors of impulses and conduct impulses towards the cell body.

Nerve cell or cell body has a nucleus and highly specialized protoplasm. The body of the nerve gives rise to nerve fibers. It receives impulses from the dendrites and sends to the axon.

Axon or nerve fiber arises from the body of each nerve cell. The impulse generation and conduction occur here. Axons conduct impulses in one direction only, i.e. towards the axon terminals. Myelin sheath is a lipid layer that covers the axons of some of the neurons (myelinated neurons).