Division of the nervous system

• Divisions of the nervous system

  • Central nervous system (CNS)
  • Peripheral nervous system (PNS)
• Central nervous system


  Brain and spinal cord
• Autonomic nervous system


  • Sympathetic nervous system
  • Parasympathetic nervous system
• Somatic nervous system


  Contains sensory and motor neurons
• Sensory neurons


  • Take impulses from sense organs to the central nervous system
• Motor neurons


  • Take impulses from the CNS to muscles and glands (effectors)
• Sympathetic and parasympathetic systems

  Have antagonistic actions that affect heart rate, breathing rate, peristalsis and intestinal secretions
• Sympathetic nervous system


  Releases noradrenaline to speed up heart rate
• Parasympathetic nervous system


  Releases acetylcholine to slow down heart rate
• Neural pathways


  • Converging
  • Diverging
  • Reverberating
• Converging neural pathway


  • Impulses from several neurons travel to one neuron, increasing the sensitivity to excitatory or inhibitory signals
• Diverging neural pathway


  • Impulses from one neuron travel to several neurons, affecting more than one destination at the same time
• Reverberating pathway


  • Neurons later in the pathway link with earlier neurons, sending the impulse back through the pathway, allowing for repeated stimulation