The Brain

 

THE BRAIN

The Cerebrum is the largest part of the brain and is composed of right and left hemispheres which are joined by a bundle of fibers called the Corpus Callosum that delivers messages from one side to the other.

Each hemisphere controls the opposite side of the body. If a brain tumor is located on the right side of the brain, your left arm or leg may be weak or paralyzed. However, not all functions of the hemispheres are shared:

• The left hemisphere controls speech, comprehension, arithmetic, and writing and is dominant in hand use and language in about 92% of people.
• The right hemisphere controls creativity, spatial ability, artistic, and musical skills.

The Cerebrum performs higher functions like interpreting touch, vision and hearing, as well as speech, reasoning, emotions, learning, and fine control of movement.

Each hemisphere has four lobes:

Frontal Lobe

• Personality, behavior, emotions
• Judgment, planning, problem solving
• Speech: speaking and writing (Broca’s area)
• Body movement (motor strip)
• Intelligence, concentration, self awareness

Parietal Lobe

• Interprets language, words
• Sense of touch, pain, temperature (sensory strip)
• Interprets signals from vision, hearing, motor, sensory and memory
• Spatial and visual perception

Occipital Lobe

• Interprets vision (color, light, movement)

Temporal Lobe

• Understanding language (Wernicke’s area)
• Memory
• Hearing
• Sequencing and organization

The surface of the Cerebrum has a folded appearance called the Cortex which contains about 70% of the 100 billion nerve cells. The folding of the cortex increases the brain’s surface area allowing more neurons to fit inside the skull and enabling higher functions.

The Cerebellum is located under the Cerebrum and coordinates muscle movements, maintain posture, and balance.

The Brainstem acts as a conveyer connecting the cerebrum and cerebellum to the spinal cord, performing many automatic functions such as breathing, heart rate, body temperature, wake and sleep cycles, digestion, sneezing, coughing, vomiting, and swallowing. Ten of the twelve cranial nerves originate in the brainstem.