Question

White matter is composed of-
A) Nerve cells
B) Nerve fibers
C) Ependymal cells
D) None of these

Answer 1

Hint: As we know that, the central nervous system is made up of gray matter and white matter. White matter is a component of the central nervous system, consisting of neuron cell bodies, synapses. It is mainly located on the surface of the spinal cord and brain. The white matter in the center of the cord is shaped like a butterfly and consists of cell bodies of interneurons and motor neurons as well as neuroglia cells and unmyelinated axons. Grey matter, on the other hand, is crucial in helping humans to operate normally on a regular basis.

Complete answer:
A) Nerve cells- a nerve cell or also called a neuron is an electrically excitable cell that communicates with other cells via specialized connections called synapses. Except for sponges, it is the major component of nerve tissue in all animals. Nerve cells do not exist in plants or fungi.
Option A is not correct.
B) Nerve fibers- white matter is found in the deeper tissues of the brain. It contains nerve fibers which are extensions of nerve cells only. Many of these nerve fibers are surrounded by a type of sheath or covering called myelin. White matter is composed of long myelinated axons.
So, option B is correct.
C) Ependymal cells- it is a type of neuronal support cell that forms the epithelial lining of the ventricles in the brain and the central canal of the spinal cord. The function of ependymal cells is to produce and regulate the CSF.
So, option C is not correct.
D) None of these-this option is inappropriate as one the above options are correct.
So, option D is not correct.

Hence, Option B is the correct answer.

Note:
As we discussed what is white matter composed of, the color is light because of the presence of low axons than grey matter. Grey matter is present both in the spinal cord as well as the brain. Their function is to carry neurons which leads the neuro activities of the body. Gray matter consists of dendrites and soma which process the information. Processing of information is the conduction of neural activity. It consists of predominantly neuronal cell bodies. Many issues may affect the grey matter both in the brain and spinal cord, one of the most prevalent medical problems occurs when plaque begins to build up in areas of grey matter within the brain.