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How The Human Nervous System Works

Updated on November 16, 2013 (public domain) (public domain) | Source

The Nervous System

The nervous system is a network of specialized cells and tissues which is present in all animals consisting of several cells (multicellular) to a greater or lesser degree, but with the exception of sponges. The operation of the nervous system and its activity consists of electrical impulses which are caused by the movement of chemical ions, or in other words, those chemical ions are potassium and sodium.

The nervous system includes receptors, and these receive information from the surrounding environment and are called sensory. These are concerned and related with the senses such as sound, sight, touch and pressure and they transmit the information which they detect along nerves called the sensory nerves, and these travel to the central nervous system. If you refer to the image above: number 1 is the brain, 2 is the central nervous nervous system (the brain and the spinal cord), and the 3 is the spinal cord.

In the simpler animals such as invertebrates (having no spinal column), this often consists of a paired nerve cord with swellings along its length called ganglia (ganglion). In vertebrates (having a backbone or spinal column), the central nervous system is very complex and consists of the brain and spinal cord.

Within the central nervous system all the information is decoded and, if appropriate, a response is initiated. This often consists of a signal being sent outwards along a nerve which is called a motor nerve, which travels to a muscle causing a contraction to occur. In vertebrate animals, a part of the nervous system is concerned with the control of the involuntary or smooth muscle of the body. This is called the autonomic nervous system (ANS) and consists of two divisions, the sympathetic and parasympathetic which act in opposite ways, known as antagonistic.

It is sometimes called involuntary or the visceral nervous system because its activity regulates the internal environment of the body and it supplies the smooth muscle such as the heart and gut and other muscles for example, and glands with their motor nerve supply.

Diagram of the Nerve Cells (public domain) (public domain) | Source

Basic explanation of the nerves

A nerve is made up of several nerve cells also known as neurons or can be spelled as neurones. SO basically some nerves are sensory, others are motor and yet others are mixed carrying both types of nerve cells (neurons). Each neuron has a cell body, containing the nucleus, and many fine projections called dendrites. Dendrites from surrounding neurons are able to communicate with one another across a gap called a synapse. A long, fine projection runs out from the neuron cell body and this is called an axon (please refer to the diagram for all the scientific terms). It may be surrounded by a fatty sheath called a myelin sheath which is restricted at intervals at sites which are known as nodes of Ranvier.

The Brain and the Central Nervous System


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    • ananceleste profile image

      Anan Celeste 5 years ago from California

      Magnificent and informative Hub! The complexity and perfect design of the human body is mind boggling. An intricate network of components that make organisms the perfect computer. Blessings.

    • aziza786 profile image

      Zia Uddin 5 years ago

      Thank you both for commenting. Merry Christmas and Happy New Year.

    • Nyamache profile image

      Joshua Nyamache 5 years ago from Kenya

      Now I have gathered knowledge from your hub, the clear diagram naming the nerve cells. Very useful and thanks for sharing this.

    • Deborah Brooks profile image

      Deborah Brooks Langford 5 years ago from Brownsville,TX

      what great information this is, I do know if one little thing is out of whack in our nervous system or brain or spinal cord our bodies can go haywire.. I still believe in eating right working out and maybe just maybe you have a better chance at staying healthy.. but you never know what is going to happen day to day. you can have a accident and damage your spinal cord etc..

      This is a great hub

      Many blessing

      Merry Christmas and Happy New year