Just three pounds of neurons and connective tissue enable you to speak, breathe, dream, think, and, basically, to be yourself. The brain is an incredible organ that begins to form within weeks of conception. Although there are many specific parts to the brain, most scientists break it down into three major parts: the cerebrum, cerebellum and brain stem.
The Cerebrum
The cerebrum is the largest part of the brain, according to Serendip, an organization at Bryn Mawr College. Also known as the cortex, this wrinkled mass of neurons is responsible for human qualities, including planning, speech and memory. The cerebrum consists of four major sections, or lobes, says the Centre for Neuro Skills. The lobe nearest the ears, the temporal lobe, is primarily responsible for hearing. The lobe at the back of the head, the occipital lobe, is responsible for vision. The parietal lobe, consisting of the top portion of the brain, enables voluntary movement and object recognition. The most evolved part of the brain is the frontal lobe. According to the Alzheimer's Association, this lobe enables people to make plans, engage in problem solving, and remain in control of emotions and speech. The cerebrum is also separated into two halves, or hemispheres. A thick bundle of neurons called the corpus callosum connects these hemispheres and enables them to communicate with one another.
The Cerebellum
The cerebellum looks like a miniature brain perched at the lower rear of the cerebrum. This is an evolutionarily older portion of the brain than the cerebrum, thus it performs more basic functions. Most notably, the cerebellum allows people to maintain balance and coordination, according to the Alzheimer's Association. The Centre for Neuro Skills reports that when the cerebellum is damaged, a person cannot walk, grab objects or coordinate his movements. Slurred speech may occur, an indication that many parts of the brain contribute to the same activities, such as speaking.
The Brain Stem
The most basic part of the brain is the brain stem. Located at the very base of the neck, this area of the brain controls respiration, heart rate and blood pressure. The brain stem enables people to stay alert, sleep and digest food. When a person is pronounced "brain dead," it means that her brain stem is still functioning, enabling her basic functions to continue, but her cerebrum is no longer intact.
