Brain stem
Though the brainstem is small, it is extremely important. The motor (movement) and sensory connections from the main part of the brain to the rest of the body pass through the brain stem. Also, from the brainstem come the main motor and sensory nerves to the face and neck. These nerves are called the cranial nerves. The brainstem controls many bodily functions of which we are not normally aware, such as breathing, heart beat, and sweating. The brainstem controls functions which are unconscious, but necessary for life.