Overview, functions, structure and types

Neurons are information-carrying cells within the central nervous system (CNS) and peripheral nervous system (PNS). The CNS includes the brain and spinal cord, while the PNS includes neurons in the rest of the body. Neurons use electrical impulses and chemical signals, called neurotransmitters, to communicate information through the CNS and PNS.

If you’ve ever wondered how our mind and body work together, allowing us to consciously move, feel and think, it all starts with neurons. This article provides an overview of neurons, their structure, types, and function.

zf L / Getty Images

Structure of neurons

Most neurons have three parts: a cell body, a axonand dendrites.

The cell body

The cell body of the neuron contains core. The nucleus contains our genetic information. It also includes the cytoplasmwhich is the fluid that houses the majority of the cellular material in the neuron.

Axons

An axon is a long, narrow connecting line that branches away from the cell body to send electrical impulses to other neurons. Thanks to these impulses, axons are responsible for the active transmission of information throughout the body.

Axons look like long tails. They branch into many smaller branches that reach the axons of other neurons.

Dendrites

Dendrites also extend from the cell body of the neuron, but they are responsible for receiving messages from other neurons.

Dendrites, which look like tree branches, collect information to bring it back to the neuron. The tip of each dendrite is a contact point that allows one neuron to connect to another. These contact points are called synapses. Dendrites have a lot of them.

Glial cells

Neurons depend on another type of cell called glial cells. Glial cells are sometimes called “nerve glue” because they provide connectivity between neurons to allow the movement of information. They help transport nutrients, hormones and neurotransmitters.

Types of neurons

There are different types of neurons including motor, sensory and interneurons.

Motor neurons

Motor neurons transmit electrical impulses and information from the CNS to the muscles of the body. Motor neurons control all of our bodily movements.

There are two main subtypes of motor neurons:

Upper motor neurons: Sends data from the brain to lower motor neurons
Lower motor neurons: Sends data from the upper motor neurons to the muscles of the body

sensory neurons

Sensory neurons are neurons that allow us to experience sensation. For example, if you stub your toe, sensory neurons will send chemical and electrical impulses back through the nervous system to tell your brain that you are feeling pain in your toe.

Sensory neurons can be activated physically, like feeling touch, or chemically, like tasting a piece of cake. Our five senses – hearing, sight, touch, smell and taste – are influenced by sensory neurons.

Interneurons

Interneurons are nerve cells that connect between motor neurons and sensory neurons. Interneurons can also send information to and from other interneurons.

How do neurons work?

Neurons work by sending chemicals, called neurotransmitters, through a small area between the axon of one neuron and the dendrite of another. This small space that allows the exchange of information is called a synapse.

Neurons also allow the CNS and PNS to report information instantly and constantly. This exchange of information allows us to think, speak, feel, move and do whatever our body is capable of.

Neural functions

The function of a neuron is to send electrical impulses and chemical signals to and from the brain.

Neurons accomplish this task using a process called “action potential”. The action potential is the rapid flow of electrical voltage from the neuron to the axon. This voltage allows information to be transmitted from neuron to neuron throughout the body.

Summary

Neurons carry signals in the central and peripheral nervous systems. Their function is to send electrical impulses and chemical signals to and from the brain.

Most neurons have three parts, including a cell body, which contains the nucleus and cytoplasm, an axon, which transmits information out of the nucleus, and dendrites, which receive messages from other neurons.

The main types of neurons include motor neurons, which transmit information to our muscles, sensory neurons, which transmit information to activate our senses, and interneurons, which facilitate transmission between motor and sensory neurons.

A word from Verywell

Neurons are essential to human life. They allow our body and brain to communicate and allow us to think, feel and move. Further research can help us understand the complexity of how neurons work.

Frequently Asked Questions

What is a neuron?

Neurons are information-carrying cells within the central nervous system (CNS) and peripheral nervous system (PNS). They work by allowing the CNS and PNS to communicate information to each other, which allows us to think, speak, feel and move.

Where are neurons located in the body?

Neurons are located in the brain and spinal cord, which are organs of the CNS. Neurons are also located throughout the rest of the body in the PNS.

What are the different types of neurons?
There are three main types of neurons:
- Motor neurons connect the brain to muscles throughout the body. These neurons transmit electrical impulses containing information to skeletal muscles and smooth muscles. Motor neurons control all of our bodily movements.
- Sensory neurons are neurons that allow us to experience sensation. If you burn your hand, sensory neurons will send chemical and electrical impulses back through the nervous system to let your brain know you’re feeling pain in your hand.
- Interneurons are the nerve cells that connect motor neurons to other motor neurons and sensory neurons to other sensory neurons.