Say you accidentally put your hand down on a hot stove. Yow!

The stimulus, which in this case is heat, will trigger your peripheral nervous system. We know it's peripheral because the peripheral system carries nerve impulses to and from the body to the central nervous system (composed of the spinal cord and brain which then analyzes the "message" and issues directions accordingly).

When the central nervous system receives the "Hot!" message, it issues a command to motor nerves, which activate the muscles, tendons and bones that yank your hand away.

5.
Remember our "Yow! Hot!" example?

Where does the "Hot!" message enter the spinal cord?

Where does the "Yank!" message exit it?