Question

Which of the following is a part of a neuron?
a. Axon
b. Cell body
c. Dendrite
d. All of the above

Answer 1

Hint: Neurons are structural and functional units of the nervous system. They are terminally differentiated cells, that is they leave the cell cycle once they mature. Neurons function to carry impulses to and from the brain. They resemble all other cells of the body, with specialized features to transmit electrical signals.

Complete answer:
The nervous system comprises special cells that are capable of transmitting electrical and chemical signals. The cells are called neurons.
The structure of a typical neuron can be delineated as follows:
A neuron comprises a cell body, axon and dendrites.
> Cell body: the cell body of a neuron is also known as soma. The soma contains cellular organelles and the nucleus. It contains the genetic material which forms various proteins in the cell. The soma is covered with a protective membrane.
> Axon: The axon is a slender tail like projection from the cell body. The axon is covered by a Myelin sheath which functions to insulate it. The presence of the Myelin sheath helps in rapid transmission of signals. The Myelin sheath is discontinuous at the Nodes of Ranvier. The axon terminates in several branches at the axon terminal. Each axon terminal is a button like structure that contains the neurotransmitters. Neurotransmitters help in transfer of signals from one neuron to another.
> Dendrites: They are the root like projections of the cell body. It is through the dendrites most of the nerve impulses enter the neuron from other neurons. The dendrites can be short or long. The dendrites receive chemical signals and convert them into electrical signals and then transmit the same to the cell body.
Therefore, it can be concluded that the different parts of a typical neuron are cell body or soma, axon and dendrites.

Hence, option (d) is correct.

Note: Neurons form specialized units of the nervous system. They are composed of a cell body, axon and dendrites. One neuron is connected to another neuron with the help of synapses. The messengers at the synapses that carry impulses are called neurotransmitters. Neurons carry impulses to and from the brain. Neurons are formed during embryonic development by a process called neurogenesis and are numerous at birth. They do not reproduce and thus cannot be replaced once they die.