1. The Nervous System
7.12 B

2. Functions of the Nervous System
Receives Information from inside and outside of the body
Directs how the body responds to information
Maintains stable internal conditions.

3. Can you move without your nervous system?
What happens when you are paralyzed?

4. From what two places does the nervous system receive information?
Environment
Inside the body

5. A stimulus can make an organism respond or react.
Nervous system responses are not all voluntary
Nervous system directs the body to respond appropriately to the information it receives.

6. The Neuron
Axon: An extension from a nerve cell that carries impulses away from the nerve cell
Dendrite: an extension from a nerve cell that carries impulses toward the nerve cell.

7. Neuron: A cell that carries information through the nervous system.
Nerve impulse: The message that a nerve cell carries.

8. Cell (NEURON) vs Tissue (NERVE)
Neurons: only have one axon
Nerve: a bundle of nerve fibers

9. Interneuron: A neuron that carries nerve impulses from one neuron to another.
Motor Neurons: A neuron that sends an impulse to a muscle, causing the muscle to contract.
Sensory Neuron: A neuron that picks up stimuli from the internal or eternal environment and converts each stimulus into a nerve impulse.

11. Brain: The part of the central nervous system that is located in the skull and that controls most functions in the body.

12. Synapse
Synapse: The tiny space between the tip of an axon and the next structure.

13. How do messages get across the synapse?
Axon tips release chemicals that enable the impulse to cross the synapse to the next nerve or tissue.