Question

Nerve fibre is
A)A thin nerve
B)Fibre formed by many axons
C)Fibre formed by ensheathing of axon in myelinated fibre
D)Fibre formed by ensheathing of a dendrite

Answer 1

Hint: Neurons are also called the nerve cells. Neurons or nerve cells are the structural as well as the functional unit of neural system. On an average, the human brain is made up of more than 100 billion neurons. Similarly, other parts of the neural system, whether of CNS or of PNS, are structurally made up of a large number of neurons.

Complete answer:
Neuron contains following part:

1)Dendrites: From the cell body, short fibres arise out. These short fibres which arise out from the cell body are called the dendrites. The dendrites branch repeatedly to further give rise to smaller fibres. The dendrites also contain the Nissl's granules, like the cell body. The dendrites of one neuron receive the electrical impulses from different sources, i.e., other neurons and then transmit these impulses towards the cell body of the neuron to which they belong.

2)Cell body : Cell body is the controlling part of the neuron. The cell body contains cytoplasm with a nucleus in the central The cytoplasm of the cell body contains typical cell organelles like Golgi apparatus, endoplasmic reticulum, ribosomes, mitochondria, etc. The cytoplasm also contains certain granular bodies called Nissl's granules. These granular bodies give a slight colour appearance to the cytoplasm of the cell body. The function of Nissl's granules is supposed to be the protein synthesis in the body of neurons

3)Axon : Next major part of the neuron is the axon. The axon is also called the nerve fibre. The axon is a long fibre which arises from the cell body. Each neuron may have many dendrites but has only one long fibre-like axon. That end of the axon which is attached to the cell body is called proximal end whereas the end of the axon which is away from the cell body is called the distal end. The distal end of the axon shows branching. The distal end of the axon is divided into certain branches which are called the axon terminals

Hence, the correct answer is option (C)

Note: These neurons are interlinked with each other or are linked with other cells of the body forming complex nerve connections for the exchange of neural information. Neurons are called the functional units of the neural system because the various functions of the neural systems are basically the functions of the neurons.