controlling body temprature

• what do receptors do?

  they detect a stimulus (a change in the environment, e.g temperature change)
• what do coordination centres do?

  They receive information from the receptors, process the information and instigate a response.
• where are coordination centres?

  the brain, spinal cord and pancreas.
• what is a effector?

  The organ, tissue or cell that produces a response.
• where is the thermoregulatory centre?

  the hypothalamus in the brain
• The thermoregulatory centre contains receptors sensitive to the temperature of the blood. The skin also has temperature receptors and sends nervous impulses back to the thermoregulatory centre.
• what happens if the body temprature is too high/low?

  1. the temperature receptors detect that the core body temprature has changed
  2. the thermoregulatory center receives the information and automatically triggers the effectors
  3. effectors produce a response to counteract the change
• what responces do the effectors produce when you are too hot?

  1. sweat (produced by sweat glands) evaporates from the skin, transfering energy to the enviroment
  2. blood vessels supplying the skin dilate, so blood flows closer to the surface of the skin (called vasodilation), which helps transfer energy to the enviroment
• what responces do the effectors produce when you are too cold?

  1. hairs stand up (to trap an insulating layer of air)
  2. no sweat is produced
  3. blood vessels supplying skin capillaries constrict, to close off the skins blood supply (called vasoconstriction)
  4. shivering, (mucles contracting automatically) which needs respiration (transfers energy)
• what is vasodilation?

  when the blood vessels supplying the skin dilate so more blood flows closer to the skins surface
• what is vasoconstriction?

  when blood vessels supplying the skin capillaries constrict, to close off the skins blood supply.