Psychology Textbooks Boundless Psychology Biological Foundations of Psychology The Nervous System
Psychology Textbooks Boundless Psychology Biological Foundations of Psychology
Psychology Textbooks Boundless Psychology
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Psychology
Concept Version 10
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The Central Nervous System (CNS)

The central nervous system is made up of the brain and spinal cord, which process sensory input and provide instructions to the body.

Learning Objective

  • Describe the structural elements of the central nervous system

Key Points

    • The central nervous system (CNS) and the peripheral nervous system (PNS) comprise the entirety of the body's nervous system, which regulates and maintains its most basic functions.
    • The CNS is the main control center of the body—it takes in sensory information, organizes and synthesizes this input, then provides instructions for motor output to the rest of the body.
    • The CNS is made up of the brain and spinal cord.
    • The brain is the main data center of the body, consisting of the cerebrum (which regulates higher-level functioning such as thought) and the cerebellum (which maintains coordination).
    • The brain stem includes the midbrain, pons, and medulla, and controls lower-level functioning such as respiration and digestion.
    • The spinal cord connects the brain and the body's main receptors, and serves as a conduit for sensory input and motor output.

Terms

  • brain stem

    The part of the brain that connects the spinal cord to the forebrain and cerebrum.

  • cerebellum

    Part of the hindbrain in vertebrates. In humans it lies between the brainstem and the cerebrum, and plays an important role in sensory perception, motor output, balance, and posture.

  • spinal cord

    A thick, whitish cord of nerve tissue that is a major part of the central nervous system. It extends from the brain stem through the spine, with nerves branching off to various parts of the body.

  • cerebrum

    In humans it is the largest part of the brain and is the seat of motor and sensory functions, as well as the higher mental functions such as consciousness, thought, reason, emotion, and memory.

Full Text

Introduction to the Central Nervous System

The central nervous system (CNS) is one of the two major subdivisions of the nervous system. The CNS includes the brain and spinal cord, which together comprise the body's main control center. Together with the peripheral nervous system (PNS), the CNS performs fundamental functions that contribute to an organism's life and behavior.

Activity of the CNS

The nervous system has three main functions: gathering sensory information from external stimuli, synthesizing that information, and responding to those stimuli. The CNS is mainly devoted to the "information synthesizing" function. During this step in the process, the brain and spinal cord decide on appropriate motor output, which is computed based on the type of sensory input. The CNS regulates everything from organ function to high-level thought to purposeful body movement. Thus, the CNS is commonly thought of as the control center of the body.

Structure of the Central Nervous System

The CNS is comprised of the brain, brain stem, and spinal cord.

The central nervous system

The three major components of the central nervous system: 1) the brain, 2) brain stem, and 3) spinal cord.

Brain

The brain is found in the cranial cavity and consists of the cerebrum and cerebellum. It houses the nerve centers responsible for coordinating sensory and motor systems in the body. The cerebrum, or the top portion for the brain, is the seat of higher-level thought. It is comprised of two hemispheres, each controlling the opposite side of the body. Each of these hemispheres is divided into four separate lobes:

  • the frontal lobe, which controls specialized motor control, learning, planning, and speech;
  • the parietal lobe, which controls somatic or voluntary sensory functions;
  • the occipital lobe, which controls vision;
  • the temporal lobe, which controls hearing and some other speech functions.

The cerebellum is located underneath the backside of the cerebrum, and governs balance and fine motor movements. Its main function is maintaining coordination throughout the body.

Brain Stem

The brain stem is connected to the underside of the brain. It consists of the midbrain, pons, and medulla. The midbrain is found in between the hindbrain and the forebrain. It regulates motor function and allows motor and sensory information to pass from the brain to the rest of the body. The pons houses the control centers for respiration and inhibitory functions. The medulla also helps regulate respiration, as well as cardiovascular and digestive functioning.

Spinal Cord

The spinal cord connects the brain and brain stem to all of the major nerves in the body. Spinal nerves originate from the spinal cord and control the functions of the rest of the body. Impulses are sent from receptors through the spinal cord to the brain, where they are processed and synthesized into instructions for the rest of the body. This data is then sent back through the spinal cord to muscles and glands for motor output.

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