Nervous+system+notes-+kat

Nerves are bundles of many, many nerve cells how does one neuron communicate with another neuron?
 * Spinal cord is the biggest nerve
 * The brain is the central nervous system, if you break off the signal in the middle of the spinal cord, the lower half of the body can't communicate with the upper half.
 * there are only 3 cells that connect to the brain.
 * example: touch on the side--> one cell to the spinal cord--> one cell to the brain--> one cell to the specific part in the brain
 * to react only takes 2 cells
 * sends a flash along the axon.
 * along the axon: sodium in makes it positive, potassium out makes it negative.
 * **Neurotransmitters**, the space between neurons: **synapse**
 * **positive charge cant transmit the synapse.**