- A brain is one of the body's heaviest organs consisting of millions of nerves. The average weight of a brain is 3 pounds.
- The brain cells, which are called neurons, transfer signals from the brain to other nerves of the body. The nerve fibers that signals are communicated to are called axons and dendrites.
- The brain has two large parts, the cerebrum and the cerebellum. The cerebrum is the largest part of the brain, making up 85 percent of it and is responsible for thoughts and actions. It is divided into two halves and then divided into two more, making it four parts total called lobes.
- The second largest part of the brain is the cerebellum, which is behind the cerebrum. It is responsible for muscle movements and balance control.
- The brain is a very sensitive and delicate organ, which is why brain injuries are very serious.
