Neuron and Nerves

Nerves are individual nerve cells which are a collection of neurons and part of our nervous system. These are located throughout our bodies under our skin, through and around our organs, and towards the center area of the brain. Neurons are the cells that are present in the nervous system that transmits information to other nerve cells, muscles, or gland cells. The relation between neuron and nerve is nervous tissue is made up of different types of neurons that have an axon and an axon is the long stem-like part of the cell that transmits messages to the next cell.


Difference Between Nerve And Neuron

Nerve :

  • It is a bundle of axons wrapped by the collective tissues.

  • It is covered by three layers perineurium, endoneurium, and epineurium.

  • These are found in the peripheral nervous system.

  • There are three types of nerves: afferent nerves, efferent nerves, and mixed nerves.

  • It is composed of many nerve fibers, blood vessels, and lymphatics.


Neuron :

  • It is an individual cell which is the functional unit of the nervous system

  • It has three major parts soma, dendrites and an axon

  • It is present in both the central and peripheral nervous system

  • There are three types of neurons motor neurons, sensory neurons and interneurons

  • It is composed of the axon, cell body, and dendrites


Nerve Cell Parts

Nerve cells are also called neurons. It consists of three parts which are as follows:

  • Cell Body - It contains the nucleus and other cell organelles. It is also known as (soma) the factory of the neuron. It provides and produces all the proteins for the dendrites, axons and synaptic terminals.

  • Dendrites - These are extended from the cell body and receive nerve impulses from other neurons. Dendrites are the antennae of the neuron and covered by a large number of synapses.

  • Axon - It is a long extension of the cell body that transmits nerve impulses to other cells. The branches of the axon at the terminal are known as axon terminals. At these terminals, neurons communicate with other cells. Myelin sheath is present in the axon of many neurons as an outer layer. It is a part of the motor neuron.


Working of the Neuron

The basic principle on which a neuron works is an electrically excitable cell that takes up processes and transmits information through electrical and chemical signals. With this,  human beings can react to the environment as neurons transport stimuli. As all neurons are electrically excitable, the impulse mostly arrives at dendrites which are processed into the cell body and then move along the axon. Throughout the length of an axon, it functions as an electric cable by simply transmitting the signal. Once this impulse reaches the end of the axon means synapses a special molecule called a neurotransmitter is released by the neuron. This molecule stimulates the second neuron creating a new wave of electrical impulse. In the end, the impulse reaches the required part.


Different Types of Neurons in the Nervous System 

There are basically three types of neurons which are as follows:

  • Sensory Neurons - These are the nerve cells that are activated by sensory input from the environment. Physical and chemical both inputs can activate sensory neurons that correspond to our five senses. Many sensory neurons have only one axon which is split into two branches called pseudounipolar.

  • Motor Neurons - These are present in the spinal cord part of the central nervous system which connects to muscles, glands, and organs throughout the body. The impulse from the spinal cord to skeletal and smooth muscles is transmitted through these neurons.

  • Interneurons - These are the ones that are present in between which connect the spinal motor and sensory neurons. These form circuits of various complexity while communicating signals between sensory and motor neurons.


Fun Facts

  • 7 trillion nerves are there in the human body.

  • Neurons are of different shapes and sizes depending on their location.

  • The body at rest is controlled by the nervous system.

  • If all the nerves present in the body are lined up they would stretch for almost 45 miles.

FAQ (Frequently Asked Questions)

1. What are the different types of nerves?

There are three different types of nerves: 

  • Sensory Nerves - These nerves carry impulses to the sensory receptors towards the brain. These are also called afferent nerves. These nerves have the ability to sense or recognize the stimuli and carry sensory information toward the Central Nervous System.

  • Motor Nerves - These carry impulses away from the brain to muscles and glands. These are also called different nerves. These are usually located in CNS.

  • Autonomic Nerves - An involuntary or partially voluntary action of our body is controlled by these nerves. These nerves control the internal organs without any effort by the organism.

2. What are Central and Peripheral nervous systems?

Central Nervous System

  • This system controls most functions of the body and mind consisting of the brain and the spinal cord.

  • It is responsible for sending sensory information and responding accordingly.

  • The spinal cord in the body acts as a medium for signals between the brain and the rest of the body.  


 Peripheral Nervous System

  • This system refers to the parts outside the central nervous system, the brain, and the spinal cord.

  • In this system, bundles of nerve fibers or axons carry information to and from the nervous system.

  • This system is also classified into somatic and autonomic nervous systems.