Here is a diagram of the human brain. For your GCSE biology you should be able to label this diagram and explain what the various parts do. There are three main regions of the brain: the fore-brain (green), mid-brain (red), and hind-brain (blue).
A: cerebral hemisphere
B: cerebro-spinal fluid
F: spinal cord
H: pituitary gland
There are two cerebral hemispheres, one on each side. They are very important because much of your behaviour is controlled by this part of the brain. Various areas of these hemispheres receive information from our sense organs. These sensory areas include the hearing centre, taste centre and the sight centre. Other areas are responsible for producing responses. There is a speech centre, a salivation centre and so on. When an area of the brain is damaged, e.g. by a stroke, a person can lose the ability to feel in a part of the body, or the ability to make a limb move. It is possible to lose both the feeling and the ability to move a limb.
The cerebellum is responsible for co-ordination movement. We learn how to walk, run and jump at a very early age. Although you were able to make movements when you were first born, you were not able to co-ordinate them properly and so could not walk or crawl. When you got a bit stronger, you could crawl but not walk. Balancing oneself on two feet requires information from the eyes, ears and muscles. The cerebellum puts all this information together and allows us to adjust the positions of our arms and legs when we move around.
The pituitary gland is the master endocrine gland. It is controlled by an area of the mid-brain just above called the hypothalamus. It produces hormones and controls the activities of all the other endocrine glands in your body. The most interesting enzymes produced by the pituitary gland control our sexual cycles.