Length of Nerve Cell

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“Neurons are the fundamental unit of the nervous system.”

The length of a nerve cell can vary from nanometers to meters.

Yes, it’s true.

Our body is composed of millions to billions of nerve cells. Some nerve cells can be comparatively smaller by 0.1 millimeters or can be longer by 1 meter. The size of nerve cells is usually based on their functions i.e how long electrical impulse is transmitted within our body. They are found in the brain, spinal cord and peripheral nerves.

For instance, the nerve cell, which transmits the electrical impulse from our brain to the end of the toe finger may be the largest nerve cell. The size of the nerve cell even varies with the type of organism.

Explore more about: Neurons

Let’s learn more in detail about the nerve cell and its functions.

What is Nerve Cell?

A nerve cell is also known as a neuron. It is mainly involved in receiving and transmitting information to different parts of the body.

Nerve cell or Neuron is called the main structural and functional units of the nervous system. The shape and size of the Neuron generally vary, depending upon the location and functions. A group of neurons forms a nerve and the nervous system.

Also Refer: Neuron And Nerves

Structure of Nerve Cell or Neuron

The nerve cell is a specialized and individual cell, which forms a nerve. Basically, the structure of the nerve cell comprises the following parts.

Structure of neuron

  • Dendrites

A branch-like structure that functions by receiving messages from other neurons and allows the transmission of messages to the cell body.

  • Axon

It is a tube-like structure, which functions by carrying an electrical impulse from the cell body to the axon terminals and by transmitting the impulse to another neuron.

  • Myelin Sheath

It is present in the exterior region of the nerve cell. In neurons, as per the name, the myelin sheath functions as a protective layer of the nerve cell by surrounding the nerve fibres.

  • Nucleus

Each neuron or a nerve cell has a cell body with a nucleus and other cell organelles including, the endoplasmic reticulum, Golgi apparatus, mitochondria and other components.

  • Synapse

It is also called the nerve ending or nerve junction, which is mainly involved in permitting the entry of a neuron to move electrical signals from one neuron to another neuron.

Also Refer: Structure of Nerve Cell

Types of Nerve Cell

The human body is composed of several different types of neurons, which function by facilitating the transmission of information through electrical impulses. Based on their functions, the neurons are classified into three types:

Sensory neurons

Neurons, which carry sensory impulses from sensory organs to the central nervous system (CNS) are called sensory neurons. There are about 9 to 10 million sensory nerves in the human body and are found in sense organs – eyes, ears, nose, tongue and skin.

Motor neurons

Neurons, which carry motor impulses from the central nervous system (CNS) to specific effectors, are called motor neurons. There are about 50 to 60 thousand motor neurons in the human body and are found in glands and muscles.


Interneurons are the intermediate neurons or the connector neurons of neural circuits. It is an intermediary between the two neurons and functions by passing signals and enabling communication between sensory neurons to the central nervous system and motor neurons to the central nervous system. These neurons are present all over the body, including the spinal cord and brain and are exclusively found in the central nervous system (CNS).

Functions of Nerve Cell

The nerve cell or neuron acts as the mediator and is the basic signalling unit of the nervous system. The human nervous system is a complex network of neurons specialized to carry messages. The main functions of the nerve cell are:

  1. To respond to stimuli
  2. To control the metabolic actions
  3. Regulation of physiological functions
  4. To carry messages from other neurons to the cell body
  5. To receive stimuli and send signals to the brain and spinal cord

Refer more: Human Nervous system.

This article concludes the introduction to nerve cells, their types, structure along with their functions. Stay tuned with BYJU’S Biology to learn more about the neurons, nervous tissue, neurons-nerve-impulses, their facts and other related topics.

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