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As one of the two main parts of the central nervous system, the brain is responsible for controlling all of the body's actions. Everything from walking around the neighborhood to typing a term paper to solving a complex calculus equation depends upon the brain. It also allows one to speak and also to remember. In order to accomplish all of these things, the brain receives and processes information from internal and external stimuli. The largest part of the brain, which is found in the front, controls higher-level thinking skills and processes information from the five senses. The middle part of the brain is responsible for subconscious motor skills and controlling the internal organs. The rear portion of the brain assists with additional motor skills, providing coordination for performing multiple activities at the same time. Stimulus and motor signals enter and leave the brain on nerve fibers that pass through openings in the skull.

At A Glance

  • The brain is divided into four main regions—cerebrum, brain stem, diencephalon, and cerebellum—and has many functions, including receiving and processing information from the internal and external environment, controlling motor function, thinking, decision-making, language, and memory.
  • The cerebrum is responsible for higher-level thinking, memories, motor function, and sensory interpretation. The basal nuclei, located deep in the cerebrum, are responsible for motor control.
  • The frontal lobe of the cerebrum controls motor skills, the temporal lobe deciphers auditory signals, the occipital lobe processes visual stimuli, and the parietal lobe handles sensory response.
  • The limbic system surrounds the corpus callosum and is a center for emotion and learning.
  • The brain stem is a collection of structures, such as the midbrain, pons, and medulla oblongata, that function to perform behaviors necessary for survival, such as maintaining a regular heartbeat, breathing, and optimal blood pressure.
  • The midbrain processes visual and auditory information and maintains consciousness, and the pons provides sensory input to the cerebellum.
  • The medulla oblongata provides sensory information to the thalamus and brain stem and regulates visceral organs. The reticular formation, which also has connections to the cerebrum, controls an array of body functions.
  • The cerebellum is located inferior to the occipital lobe of the cerebrum and helps with motor coordination.
  • Cranial nerves exit the inferior region of the cranium through foramina in the cranial bones and are numbered I–XII.