Anatomy and Physiology: The Nervous System

Nervous System Structure and Function

Nervous system

The nervous system serves as the chief coordinating agency. Conditions within and outside the body are constantly changing; the nervous system responds to these changes causing the body to adapt itself to new conditions so that balance is maintained.

Organisation of the nervous system:Nervous_system_diagram-en.svg

Structural divisions:

  • Central Nervous system
    • Includes the Brain and Spinal Cord
      • Spinal cord functions
        • Conduction of sensory impulses to the brain
        • Conduction of motor impulses from the brain
        • Reflex response activities


  • Peripheral Nervous System
    • Includes cranial nerves which carry impulses to and from the brain and spinal nerves which carry impulses to and from the spine

Functional divisions:

  • Somatic (voluntary) nervous system
    • Function – supplies skeletal muscle
  • Visceral (involuntary) nervous system
    • Function – supplies smooth muscle, cardiac muscle, glands
      • Autonomic nervous system – regulates involuntary motor nerves during flight, fight, freeze conditions
        • Sympathetic system
          • Adjusts response to stressful situations
        • Parasympathetic system
          • Adjusts response when stressful situations have passed

Functional Structures:

  • Neuron – nerve cell
    • Sensory – carries impulses towards the central nervous system
    • Motor – carries impulses away from the central nervous system
  • Nerve impulse
    • Electric current that spreads along a nerve fibre
  • Synapse
    • Junction between neurons where a nerve impulse is transmitted from one neuron to the next
  • Nerve
    • Bundle of nerve cell fibres outside the Central Nervous System
  • Reflex Arc
    • Pathway through the nervous system