Co-ordination & control

• • Receptors and effectors are linked by co-ordinator which is normally —> brain or spinal cord
  • Together they are knows as the central nervous system
• How the central nervous system works is —>

  
• • Many of our actions are voluntary
  • This means we chose to do them and they involve conscious thought
  • However there is another type of that action that’s does not involve conscious thought these are —> reflex actions
• • Hormones is another type of communication system
  • They travel in blood and effect target organs
  • This a slower form of communication for example —> Oestorgen and Testosterone
  • Hormones are vital in maintaining a constant internet environment in the body
  • This maintenance is known as homeostasis 2 examples include —> Insulin and ADH
• Insulin is produced in the pancreas and released when levels get to high (after a meal)
• • Insulins target organ is the liver
  • Increased absorption of glucose from the blood into cells
  • Converts glucose to glycogen
  • Increased respiration
• Some of the diabetes symptoms are —> Thirsty, going to the toilet a lot and confusion
• Long term affects of diabetes are —> eye damage, heart disease and stroke
• Nervous —> voluntary (done out of there own free will or with conscious thought)

  Reflex —> involuntary (without will or without conscious thought

  
• Osmoregulation

  • We gain water from drinking and eating aswell as respiration
  • Water is lost via evaporation from lungs, sweating, urine and faeces
• Remember highlighted words and know the order of them

  
• Normally higher but can be both

  
• Sensitivity in plants

  • The response of a plant shoot to light is called phototropism
  • Plants grow and bend towards light
  • This ensures plant has lots of light so there will be more photosynthesis therefore more growth
• Sensitivity in plants

  • Produces hormone auxin in its tip
  • When plants has light from one side the auxins moves away from light to the the other side making that side grow more rapid
  • The cells on the side with no light grow by elongation (become longer) making the stem grow more on that side causing it to bend towards light. Photo —> last bullet point