The brain is far more than a 3-pound single entity housed beneath the skull. The brain is divided into three sections, each controlling a number of brain functions. Each area of the brain is important for full human functioning. In much of the brain, signals cross from one side to the other as they're relayed to the body, so damage to the right side of the brain affects the left side of the body, the National Institute of Neurological Disorders and Stroke states.
Forebrain
The forebrain is the largest part of the brain and the most specialized. The forebrain contains the cerebrum, hypothalamus and thalamus; the cerebrum is what most people think of when they think of the brain. The cerebrum is divided into right and left halves; both are covered with grooved gray matter called the cerebral cortex. Each half of the cerebrum is further divided into four lobes: the parietal, temporal, occipital and frontal lobes.
Each lobe controls different activities, such as speech, reasoning, memory and the ability to enjoy music and art. The cerebrum is the center of thinking and intellect. While the two halves look the same, they actually have different functions. The right brain controls many abstract reasoning functions, while the left brain is responsible for speech.
The hypothalamus is command central for many body functions; it controls autonomic nervous functions, body temperature and hunger and thirst. Rage and aggression impulses are also under control of the hypothalamus. The thalamus relays sensory information such as pain, pressure and touch from the spinal cord to the brain. The thalamus is surrounded by nerve cells called basal ganglia, which are necessary for movement.
Midbrain
The midbrain is the upper part of the brain stem. The midbrain transports motor impulses from the brain to the spinal cord. The midbrain controls many eye, head and trunk movements. Damage to the tegmentum, found in the center of the midbrain, can result in coma, the University of Idaho reports. The cerebral peduncle, red nucleus and substantia nigra control voluntary movements. Other parts of the midbrain include the superior colliculus, which controls eye movements, and inferior colliculus, which controls the auditory system.
Hindbrain
The hindbrain contains the medulla, pons and cerebellum. The medulla, pons and midbrain are often referred to as the brain stem. The brain stem controls reflex actions such as breathing, heart rate and blood pressure. The medulla and the pons control a number of motor functions.
The cerebellum, the second largest part of the brain, controls movement and may also be associated with emotional impulses. The cerebellum facilitates learned motor activities that require memory, the University of Idaho states. The cerebellum is covered with ridged gray matter, like the cerebrum.
