The Nervous System

If you can read this you are using your brain.

The Nervous System

The nervous system is split into two main categories: the Central Nervous System and the Peripheral Nervous System.

The Central Nervous System is comprised of the brain and spinal cord. Its purpose is to receive information and respond to it.

The Peripheral Nervous System is made of all the other nerves in the body and is meant to transmit information to and from the Central Nervous System.


The main function for all the smaller nerves in the body is to receive information from the brain and spinal cord and send it to all the other cells (usually muscle cells) of the body. The signal is sent down the nerve in the form of an electric signal. When it reaches the end of the nerve, it is converted into a chemical signal which is passed on to the next nerve cell, and then becomes an electric signal again. This process continues until the signal reaches its destination.

Spinal Cord:

The spinal cord carries messages from the brain to the rest of the nerves located throughout the body. It is protected by the spine, which encases the spinal cord. It is also capable of making very simple decisions (reflexes) without actually 'thinking'. If your sensory nerves are being caused pain (by a hot pan , a knife, etc.), the message travels to the spinal cord which immediately tells the body to move, saving time since it doesn't have to travel all the way to the brain first. (Your brain still receives the message though.)


The brain consists of three main parts: the forebrain, the cerebellum, and the brain stem. The forebrain controls conscious thought and actions, as well as senses things (through the five senses), remembers things, and feels pain.

The cerebellum controls the body's sense of balance and coordination.

The brain stem connects the brain to the spinal cord.

More Random Stuff

  • Your brain only makes up 2% of your weight but uses 20% of your body's oxygen.
  • The wrinkles in your brain help it have more surface area and make you smarter



The forebrain is made of three main parts: the cerebrum (the main part), the Limbic system, and the thalamus.

The Cerebrum:

The cerebrum makes up 85% of the brain's mass, and is divided into the right and left hemisphere. The right side of the brain controls the left side of your body, and the left side of your brain controls the right side of your body.

Left Side: The left side processes math, word, and logic skills.

Right Side: The right side controls creative and artistic skills.

Ever wonder why most people are right handed, and why?

Well even if you haven't, too bad. I'm going to tell you anyway.

For 90% of people, the left side of the brain controls fine motor hand skills. But for the rest of people, the right side of the brain controls fine motor hand skills.


  • Alzheimer's Disease results in irretrievable memory loss, and worse brain function. It is the fourth leading cause of death for the elderly. The reason for getting it is usually genes and aging, currently there is no known cure.
  • Cerebral Palsy is a movement disorder that varies in severity. The most common reason for getting it is injury to the brain or severe sickness before, during, or recently after birth. Although therapy can help, there is no known cure.
  • Down Syndrome is a form of mental retardation that you are born with. It is caused by an extra chromosome in your DNA, women over 35 are more likely to have a child with it. There is no known cure, but therapy helps.
  • Dyslexia is a condition that hinders your reading ability, the cause is still unclear. Practice and other help can fight the effects, but there is currently no known cure.

How the Nervous System Interacts with Other Systems

A lot of this will be fairly obvious to you, but keep reading, there might be something in here you don't know.

  • The nervous system interacts with the muscles of your body by sending commands from the brain, down the spinal cord, through the nerves, to the muscles, telling them what to do.
  • The circulatory system provides the entire nervous system with food and oxygen.
  • The skeletal system protects the nervous system.