- The brain is the central control of the nervous system. The brain is divided into functional parts that command different activities of the body. Even though the brain is compartmentalized, all parts communicate across each other. The brain is protected heavily by some of the hardest bone in the body called the skull. Since the brain is a vital organ in the body, it's also surrounded by a barrier called the blood-brain barrier that protects it from circulating microbes.
- The spinal cord is the extension that runs from the brain stem and down the back of the body. The spinal cord is the location of afferent and efferent sensors, which are the nerves that send and receive impulses. The spinal cord is protected by the vertebrae column and surrounded by a membrane called the meninges.
- The nervous system impulses are carried by afferent and efferent nerves. Afferent nerves are the sensory nerves. They receive stimuli from the environment for the brain to process. The brain processes information and sends the electrical impulses through the efferent nerves. Efferent nerves are also called motor nerves since these are the structures that bind to muscle and allow for movement.
- The central nervous system is a category of the nervous system. The central nervous system is comprised of the brain and the spinal cord. It is the place where activities, thoughts and responses are processed. It's estimated that there are 100 billion neurons in the brain. The neuron is the main component that processes electrical impulses.
- The peripheral nervous system makes up the nerves that extend from the spinal cord. The peripheral nervous system makes up the afferent and efferent nerves that send and receive impulses from a stimulus. They are also the nerves that extend to muscles for movement. Peripheral nerves extend all throughout the body tissue and central organs.
