Question

Draw a well labelled diagram of a neuron showing the following parts- Perikaryon, dendrites, axon, node of Ranvier, and myelin sheath.

Answer 1

Neuron

1. Neurons are the basic structural and functional units of the nervous system. It helps in relaying messages in the form of electrical impulses between sensory organs, the central nervous system, and the effector organs.
2. The neuron consists of different parts as shown in the diagram below. They are- a cell body (cyton) consisting of a nucleus, dendrites, axon with or without myelin sheath, nerve endings, and synapse.

Parts of the neuron

1. The cell body, perikaryon, or cyton houses the nucleus, mitochondria, ribosomes, and other cellular structures. They are unable to undergo cell division.
2. Axon is a long cellular process that carries the nerve impulses away from the cell body.
3. Dendrites are short, highly branched cellular processes that carry the nerve impulses towards the cell body.
4. Neurons have a thin fatty sheath around nerve fibers called the myelin sheath and such fibers are called myelinated fibers.
5. The myelin sheath is present in a discontinuous fashion leaving gaps called the nodes of Ranvier.

Labeled diagram of a neuron