Lecture Notes: The Nervous System

Introduction

• Nervous System: Referred to as the brain, it's unique due to its ability to enable humans to know oneself – consciousness or intelligence.
• Primary Function: Coordinates all body activities, enabling responses and adaptations to internal and external changes.

Division of the Nervous System

• Central Nervous System (CNS)
  • Composed of the brain and spinal cord.
• Peripheral Nervous System (PNS)
  • Will be explored later in the lecture.

Central Nervous System (CNS)

Brain

• Location: Within the cranium/skull.
• Main Sections:
  1. Cerebrum
     • Largest section, composed of right and left hemispheres.
     • Divided into four lobes:
       • Frontal Lobe: Reasoning and thought.
       • Parietal Lobe: Integrating sensory information.
       • Temporal Lobe: Processing auditory information.
       • Occipital Lobe: Processing visual information.
  2. Cerebellum
     • Located at the back of the head, responsible for muscle coordination, balance, posture, and muscle tone.
  3. Diencephalon
     • Located between cerebrum and midbrain.
     • Contains the Thalamus (sensory relay) and Hypothalamus (autonomic functions like temperature, appetite, emotions).
  4. Midbrain
     • Below cerebrum, responsible for eye and auditory reflexes.
  5. Pons
     • Below midbrain in the brain stem, controls reflex actions like chewing, tasting, and saliva production.
  6. Medulla Oblongata
     • Lowest brain stem part, connects with the spinal cord, regulates heart, blood vessels, digestion, respiration, and blood pressure.

Spinal Cord

• Function: Connects brain to nerves and body.
• Regions:
  • Cervical, Thoracic, Lumbar.
  • Afferent (to brain) and Efferent (to body) nerves merge here to form peripheral nerves.

Peripheral Nervous System (PNS)

• Overall Function: Regulates CNS functions outside major components.
• Subdivisions:
  • Somatic Nervous System
    • Manages motor and sensory information to/from CNS.
    • Connects to skin, sensory organs, skeletal muscles.
    • Handles voluntary muscle movements and sensory input processing.
    • Involves Afferent (inward) and Efferent (outward) neurons.
  • Autonomic Nervous System (ANS)
    • Further divided into:
      • Sympathetic Nervous System
        • Triggers 'fight or flight' response during danger.
      • Parasympathetic Nervous System
        • Restores normal bodily functions post-threat.

Recap

• Nervous System: Coordinates body activities, adapting to changes inside/outside the body.
• Major Parts: CNS (brain and spinal cord) and PNS (somatic and autonomic systems).
• Complexity: The lecture covers only a fraction of this intricate system.

For further videos and details on the nervous system, visit CTE skills.com.