Neurons

Table of Contents

Neuron Definition

“Neurons are the fundamental unit of the nervous system specialized to transmit information to different parts of the body.”

What is a Neuron?

Neurons are the building blocks of the nervous system. They receive and transmit signals to different parts of the body. This is carried out in both physical and electrical forms. There are several different types of neurons that facilitate the transmission of information.

The sensory neurons carry information from the sensory receptor cells present throughout the body to the brain. Whereas, the motor neurons transmit information from the brain to the muscles. The interneurons transmit information between different neurons in the body.

Also Read: Nervous System

Neurons

Neuron Structure

A neuron varies in shape and size depending on its function and location. All neurons have three different parts – dendrites, cell body and axon.

Parts of Neuron

Following are the different parts of a neuron:

Dendrites

These are branch-like structures that receive messages from other neurons and allow the transmission of messages to the cell body.

Cell Body

Each neuron has a cell body with a nucleus, Golgi body, endoplasmic reticulum, mitochondria and other components.

Axon

Axon is a tube-like structure that carries electrical impulse from the cell body to the axon terminals that pass the impulse to another neuron.

Synapse

It is the chemical junction between the terminal of one neuron and the dendrites of another neuron.

Also Read: Difference between neurons and neuroglia

Neuron Types

There are three different types of neurons:

Sensory Neurons

The sensory neurons convert signals from the external environment into corresponding internal stimuli. The sensory inputs activate the sensory neurons and carry sensory information to the brain and spinal cord. They are pseudounipolar in structure.

Motor Neurons

These are multipolar and are located in the central nervous system extending their axons outside the central nervous system. This is the most common type of neuron and transmits information from the brain to the muscles of the body.

Interneurons

They are multipolar in structure. Their axons connect only to the nearby sensory and motor neurons. They help in passing signals between two neurons.

Also Read: Nerves

Neuron Functions

The important functions of a neuron are:

Chemical Synapse

In chemical synapses, the action potential affects other neurons through a gap present between two neurons known as the synapse. The action potential is carried along the axon to a postsynaptic ending that initiates the release of chemical messengers known as neurotransmitters. These neurotransmitters excite the postsynaptic neurons that generate an action potential of their own.

Electrical Synapse

When two neurons are connected by a gap junction, it results in an electrical synapse. These gaps include ion channels that help in the direct transmission of a positive electrical signal. These are much faster than chemical synapses.

Also Read: Conduction of Nerve Impulse

For more information on neurons, their structure, parts and function, keep visiting BYJU’S website or download BYJU’S app for further reference.

Frequently Asked Questions

Q1

What is a neuron?

Neurons are the structural and functional unit of the nervous system. All neurons have three different parts – dendrites, cell body and axon. The neuron structure is specially adapted to carry messages over large distances in the body quickly in the form of electrical signals.
Q2

What are sensory neurons and motor neurons?

A sensory neuron carries impulses from the receptor to the CNS (brain or spinal cord), while a motor neuron carries impulses from the CNS (brain or spinal cord) to the effector.
Q3

Name the part of the neuron

a) Where information is acquired.

b) Through which information travels as an electrical impulse.

a) The part of the neuron which helps in the acquisition of information is known as the dendrite. They are tree-like structures that are designed to receive communications from other cells.
 
b) The part of the neuron through which information travels as an electrical impulse is known as the axon of the neuron. Axons mostly are covered with Myelin Sheath which increases the speed of signal transmission.
Q4

What is a synapse?

A synapse is the site of transmission of nerve impulses between two nerve cells (neurons) or between a neuron and a gland or muscle cell (effector). It is also known as a neuronal junction.
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