Brain anatomy. 3D artwork of a cut-away model of the human brain. At bottom is the brainstem, which controls automatic functions, sleep and arousal and relays messages from the brain to the spinal cord. Either side of the brain is the cerebellum, which controls muscle coordination and balance. The purple structure is the amygdala, which is involved in emotions, memory and fear. Hanging down from the centre of the brain is the pituitary gland, part of the endocrine (hormone) system. It secretes hormones that control control other endocrine glands and influences growth, metabolism and reproduction.