What is the Brain?

The brain is an organ that is the centre of the nervous system. It is located in the skull at the top of the spinal cord. It has three main parts: the cerebellum, the cerebrum and brainstem. The cerebrum is the biggest part of the brain. The brain is the decision-maker in the body. It decides how the body should react and respond to a condition. It memorises things and remembers them. The brain contains billions of nerve cells that send and receive information around the body. Each vertebrate and each invertebrate has a brain except jellyfish, sponges and starfish that do not have a brain.