The brain and the nervous system
The brain is the most complex organ in our body; it has two halves and sits inside the skull. One part deals with seeing, another with hearing, another with memory. With the brain we read, think, remember and count. The spinal cord lies inside the backbone and carries commands from the brain to the body. The brain, spinal cord and nerves together make up the nervous system. Sense organs send signals along nerves to the brain, the brain processes them, decides and sends commands to the muscles. For example, if your hand touches a hot teapot, the brain’s command makes you pull it away at once. The brain can be fooled: the eyes send flat pictures and the brain joins them and fills in details, which creates optical illusions. To look after the brain: sleep 9–11 hours, eat well, drink water, exercise, read and solve puzzles.
“Brain workout”: do an ordinary task with your other hand (for example, draw a line or a picture) and tell what changed. Memory game: read 10 words and write them one minute later.