nervous system

• What is the nervous system made up of ?

  • The nervous system is made up of a specialised network of cells in our body and is our primary internal communication system.
  • Its based on electrical and chemical signals compared to the endocrine system that is based on hormones.
• what are the two main functions of the nervous system ?

  • To collect, process and respond to information in the environment
  • To co-ordinate the working of different organs and cells in the body.
• The nervous system is divided into the central nervous system (cns) and peripheral nervous system (Pns)
• CNS

  • made up of the brain and spinal cord
  • The brain is the centre of all conscious awareness and is highly developed in humans. This is what distinguishes us from other animals , only few creatures ie jellyfish don't have have a brain.
  • Brain is divided into two hemispheres - the left and right
  • The spinal cord is an extension of the brain. It passes messages to and from the brain and connects nerves to the pns. Its responsible for reflex actions.
• PNS

  • transmits messages via millions of neurons to and from the CNS. The PNS is subdivided into the :

  1 - Autonomic nervous system ( ANS) - governs vital functions in the body ie breathing and sexual arousal

  2- Somatic nervous system (SNS)- Governs muscle movement and receives information from sensory receptors.
• gland- an organ in the body that creates substances such as hormones.
• Hormone- A biochemical substance that circulates in the blood but only affects target organs. they are produced in large quantities and have powerful effects.