1. Brain Everything you know is stored in your brain. The brain is about the size of a small melon. By the time you were five years old your brain had almost reached its full size. Since then it only grows a tiny bit until the age of 20.

2. Skull A set of bones which make a shell around the brain. It works like a helmet to protect the brain.

3. The brain is soft. It can be damaged if it is bumped against the bones of the skull. There are three layers of soft tissue and liquid to help protect the brain.

4. Three main parts to the brain The largest part of the brain. It does the thinking, solves problems, and helps you learn. The outer layer does much of this work. It is called the cerebral cortex. It takes messages from the sense organs and decides what the messages mean.

5. Three main parts to the brain (cont) This is the middle part of the brain. It is half the size of the cerebrum. It makes sure your muscles work together.

6. Three main parts to the brain (cont) This is the part of the brain closest to the neck. It connects to the spinal cord. Messages from your brain pass through your brain stem into your spinal cord and then your nerves.

7. It is the lowest part of the brain stem. It controls many of the inner organs that keep your body alive.

8. The cerebrum and the cerebellum are divided into two halves. The left half controls the right side of the body. The right half controls the left side of the body. If you write right handed, then the left side of the brain has more control. If you write left handed, then the right side of the brain has more control.

9. cerebrum cerebellum Brain stem Medulla oblongata