| A | B |
|---|
| nervous system | control system made up of the brain, spinal cord and nerves |
| nerve cell | can receive and send messages |
| nerve | a bundle of nerve cells |
| brain | control center of the body |
| cerebrum | largest part of the brain that controls all of your thinking |
| cerebellum | part of the brain the helps muscles work together and the body keep its balance |
| brain stem | smallest part of the brain responsible for involuntary actions that keep you alive |
| spinal cord | thick cord of nerves in the middle of the back |
| voluntary actions | actions that are controlled by thinking |
| involuntary actions | actions that occur without having to think about them |
| sensory nerve cells | nerve cells that carry messages to the spinal cord and the brain |
| motor nerve cells | nerve cells that carry messages away from the brain and spinal cord |
| connecting nerve cells | nerve cells that connect sensory nerve cells with motor nerve cells |
| reflex | a quick, automatic action |
| endocrine system | control system made up of glands |
| glands | organs or tissues that make and release chemicals |
| hormones | chemicals made by the endocrine glands |
