Central+Nervous+System

=Central Nervous System =


 * Central Nervous System **

The central nervous system (CNS) is made up from the spinal cord and the brain. These are the two parts of the central nervous system. It is the processes center for the nervous system.


 * The Spinal Cord **

There is 31 spinal nerves going up the the spinal cord. They are called mixed nerves because everyone has a sensory and motor axons. Inside the spinal column the sensory axons go through the dorsal root ganglion from there their cell bodies are located and then they go onto the spinal cord. The motor axons go through the ventral roots before meeting up with the sensory axons and becoming mixed nerves. The spinal cord nerves send information from body organs and external stimuli to the brain. Once in the brain it will send information to other parts of the body. The motor information is sent from to the brain to places like the skeletal muscles, cardiac muscle, smooth muscle, and glands.   

    The brain controls your whole body. Nerves send information to the brain and then the brain will send a message back. The brain will get sensory information from the spinal cord and from its own nerves. The three parts to the brain are the forebrain, midbrain, and the hindbrain. Most of the brains volume is processing its many sensory inputs and motor outputs.  
 * The Brain **
 * White Matter vs. Gray Matter**

The spinal cord and the brain have white and gray matter. The white matter is bundles of axons each coated with a sheath of myelin. The dark matter is masses of cell bodies and dendrites each covered with synapses. So in the spinal cord the white matter is at the surface and the gray matter is inside. In the brain for mammals it is switched.

[] [] []
 * References**