Question

Grey matter is composed of-
a. Ependymal cells
b. Nerve cells
c. Nerve fibres
d. Nissl granules

Answer 1

Hint: The grey matter is associated with the sensory motor system in our body. They are associated with the unmyelinated cells of our body. They help in impulse propagation and proper functioning of our body.

Complete answer:
The grey matter refers to that part of the neuron which is not surrounded by the myelin sheath. The nerve cells or the soma along with its dendrites are not covered with the myelin sheath. So they constitute the grey matter. Option (b) is the correct answer.

The Ependymal cells are the glial cells which are present in the choroid plexus. These cells together take part in cerebrospinal fluid formation. They are not composed of grey matter. Option (a) Ependymal cell is incorrect.

The nerve fibres are myelinated. So, they form the white matter. Option (c) Nerve fibre is incorrect.

The nissl granules are the ribosomes that are present in the nerve cell. They are not composed of grey matter. Option (d) Nissl granule is also incorrect.

Hence, The correct answer is option (B).

Additional information:
Grey matter is a major component of the central nervous system in our body. They contain neuronal cell bodies, dendrites, unmyelinated axons, glial cells, synapses and capillaries in them. Grey matter is distributed at the surface of the cerebral hemispheres. Grey matter in the spinal cord is known as the grey column. They travel down the spinal cord and get distributed in three grey columns. The grey matter present on the left and right side is connected by the grey commissure.

Note: Most of the brain's neuronal cell bodies are contained in grey matter. The grey matter also includes the regions of the brain which are involved in muscle controlling, and sensory perception like seeing, hearing, memory, emotions, speech, etc. The anterior grey column contains motor neurons and the posterior grey column contains sensory neurons synapse points. They receive sensory information from the body, and soon this information is sent from receptors of the skin, bones, and joints to the spinal cord in spinal tracts.