The Nervous System

The Nervous System

1. The Nervous system is a network of nerve cells and fibres which transmits nerve impulses between parts of the body to regulate behaviour in response to the environment.

2. Central Nervous System (CNS)

   • Made up of the Brain and Spinal Cord
   • It is the origin of all complex commands and decisions
   • It is the central processing unit (using the computer model)

3. Peripheral Nervous System (PNS)

   • Automatic Nervous System (ANS)
     • Sympathetic Nervous System
       • Arouses the body.
       • Known as the 'fight and flight' response
       • Effects on the body
         • Increase in glucose production
         • Pupils dilate to allow more light in to see far away
         • Saliva production inhibited
         • Breathing rate increases. More oxygen to muscles
         • Blood flow diverted from skin to muscles
         • Heart rate increases
         • Blood flow away from digestive organs
     • Parasympathetic Nervous System
       • Relaxes the body.
       • Known as the ' rest and digest' response
       • Effects on the body
         • Pupils Dilate
         • Release of bile
         • Decrease in glucose conversion
         • Peristalsis stimulated
         • Saliva production stimulated
         • Breathing rate decreases
         • Heart rate decreases
         • Blood diverted to digestive system
     • Transmits info to and from the CNS
     • 'autonomic' because it operates involuntarily
   • Somatic Nervous System (SNS)
     • Transmits info to the CNS and it receives info from the CNS to control voluntary muscle movement.
     • Connects the CNS and the senses.