Biology: nervous system

nervous control
1. peripheral nervous system
  1. detect stimuli and send impulses to CNS
  2. neurons
    1. motor neurone
      1. carry electrical impulses from CNS
        to the effectors (muscles)
    2. sensory neurone
      1. carry electrical impulses from receptors
        to the CNS
2. Nervous pathway
  1. stimulus
    1. receptor
      1. sensory nerves
        CNS
        motor nerves
        effector
        response
responses
1. voluntary
  1. slow and involves brain
2. involuntary
  1. fast and involves spinal cord
  2. reflex actions
neuro-transmitters
1. synapse
  1. gap between 2 nerve cells
    1. impulse reaches end of one nerve + causes release of chemicals
      1. these are called neuro-transmitters
2. drugs
  1. released from storage site in neurons
    1. increases activity
the eye
1. iris
  1. controls how much light enters eye
2. pupil
  1. lets light into eye
  2. appears black because chloroid is visible
3. cornea
  1. transparent layer
  2. refraction of light rays
4. retina
  1. contains light sensitive cells
    1. cones
      1. see colour
      2. work in bright light
      3. found in centre of retina
    2. rods
      1. see b&w
      2. work in dim light
      3. found around sides
5. lens
  1. object far
    1. long and thin
  2. object near
    1. short and fat
6. optic nerve
  1. sensory neurones
    1. carry nerve impulses to visual centre
7. acommodation
  1. change that must occur to see one object far and one near
    1. refraction of light
      1. far
        refracted less
      2. close
        refracted more
    2. ciliary muscle
      1. far
        relax
      2. close
        contract
    3. ligament
      1. far
        tight
      2. close
        relax
8. sensitivity
  1. ability to perceive, process, conduct stimuli and react

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Biology: nervous system

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	Created by cleo.moseley9 over 9 years ago