nervous system

• information about a sharp point touching the skin and how it reaches the brain:

  • sharp point stimulates pain receptor in the skin
  • this sends a nerve impulse
  • via the sensory neurone
  • which goes through the spinal cord
  • which crosses the synapse
  • which goes to the relay neurones in the brain
• the function of receptors is to:

  • detect changes in the environment
  • to convert this information
  • into impulses
• in vertebrates the central nervous system consists of the brain and spinal cord only. In mammals the central nervous system is connected to the body by sensory and motor neurones.
• sensory neurones carry information as electrical impulses from the receptors to the central nervous system.
• motor neurones carry electrical impulses from the central nervous system to the effectors
• effectors consist of all your muscles and glands which respond to nervous impulses
• receptors detect stimuli
• effectors respond to nervous impulses to bring about a change
• muscles and glands are known to be effectors but they respond differently:

  • muscles contract in response
  • glands secrete hormones
• how impulses travel between neurones

  • the chemical is released
  • it then diffuses across the synapse
• a mutation is a change that occurs in a gene