Central Nervous System

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The Central Nervous System

  • The central nervous system (CNS) is composed of the brain and spinal cord, playing a crucial role in processing and transmitting information throughout the body.

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Components of the Central Nervous System

  • Brain

    • Comprised of various regions that specialize in different functions.

  • Spinal Cord

    • Connects the brain to the rest of the body, facilitating communication via nerve signals.

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Brain: Cerebrum

  • Divided into left and right hemispheres.

  • Connected by the corpus callosum, enabling communication between hemispheres.

  • Cerebral Cortex

    • Outermost layer of the cerebrum composed of gray matter (nonmyelinated).

    • Responsible for higher functions: mind, intellect, and awareness.

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Cerebrum: Five Lobes

  • Superficial Lobes:

    • Frontal Lobe: Involved in general intellect and motor control.

    • Temporal Lobe: Processes auditory input and interpretation.

    • Parietal Lobe: Handles general sensory input and its interpretation.

    • Occipital Lobe: Responsible for visual input and its interpretation.

  • Central Lobe:

    • Insular Lobe: Associated with emotions and self-perception.

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Diencephalon Structure

  • Diagram of the brain indicating the various lobes along with the diencephalon that includes the midbrain, pons, cerebellum, and brain stem.

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Cerebrum: Regions of Interest for Exercise Physiology

  • Primary Motor Cortex (Frontal Lobe):

    • Controls voluntary skeletal muscle movements via the corticospinal tract.

  • Basal Ganglia (Cerebral White Matter):

    • Involved in initiating sustained or repetitive movements such as walking and maintaining posture and muscle tone.

  • Primary Sensory Cortex (Parietal Lobe):

    • Processes sensory information coming from the body.

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Brain: Diencephalon

  • Thalamus:

    • Major sensory relay center; determines conscious awareness.

  • Hypothalamus:

    • Maintains homeostasis by regulating the internal environment including appetite, food intake, thirst, fluid balance, sleep, blood pressure, heart rate, breathing, and temperature regulation.

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Brain: Cerebellum

  • Coordinates rapid, complex movements, ensuring correct timing and sequence.

  • Compares intended movements with actual movements, allowing for corrections based on inputs from the primary motor cortex, essential for refining movement and maintaining body positioning.

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Brain: Brain Stem

  • Serves as the information relay pathway between the brain and spinal cord and comprises the midbrain, pons, and medulla oblongata.

  • Reticular Formation:

    • Coordinates skeletal muscle functions and maintains tone; regulates cardiovascular and respiratory functions.

    • Involvement in pain modulation through opioid substances release, such as b-endorphin during exercise.

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Spinal Cord

  • Continuous with the medulla oblongata, facilitating two-way nerve impulse conduction through tracts of nerve fibers.

  • Ascending Afferent Fibers:

    • Carry sensory information to the brain.

  • Descending Efferent Fibers:

    • Carry motor commands from the brain to the body.