B1.2 The nervous system

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Created by: ell1e24
Created on: 19-02-16 18:47

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B1.2 The nervous system
- the nervous system is what allows you to respond to changes in the enviroment you are in
- Allows you to coordinate your actions
- made up of neurones
- Stimuli and receptors
  - a change in the environment is called a stimulus
  - Stimuli are detected by groups of cells called receptors
    - they change stimulus energy into electrical impulses
  - Receptors are found in the five sense organs
    - eyes- contain light receptors which are sensitive to light
    - Ears-they contain sound receptors which are sensitive to sound, also contain balance receptors which are sensitive to change in position
    - nose- contains smell receptors which are sensitive to chemical stimuli
    - tongue- contains taste receptors which are sensitive to chemical stimuli
    - skin- receptors sensitive to touch,pain, pressure and temperature change
- The central nervous system (CNS)
  - where all the information from the receptors is sent and where reflexes and actions are coordinated
  - consists of the brain and spinal cord.
  - neurones transmit information as electrical impulses to and from CNS. This is very quick
  - effectors
    - instructions sent along neurones to the effectors
    - effectors are muscles or glands which respond to nervous impulses and bring about a response to the stimulus
      - respond in two different ways
        muscles contract
        
        glands secrete hormones
  - Different types of neurone
    - Sensory neurones- nerve cells that carry signals as electrical impulses from receptors in sense organs to the CNS
    - Relay neurones- the nerve cells that carry signals from sensory neurones to motor neurones. Found in CNS
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