Communication and homeostasis

• Negative feedback

  Restoring the conditions back to normal level when the body detects a deviation
• Positive feedback


  When a deviation from the set limit triggers a response to increase the deviation further
• Thermoregulation

  • If the body temperature dropped too low, there would be insufficient kinetic energy for enzyme-controlled reactions
  • If the body temperature increased too high, enzymes would denature
• Ectotherms

  • Cannot regulate their internal temperature and can only control it through chaning their behaviour

  Ectotherms within aquatic environments wouldn't have much need to regulate their body temperature.

  • This is because water has a high specific heat capacity, and therefore the temperature remains relatively constant.
  • Ectotherms on land bask on hot rocks, to combat the temperture of the air fluctating.
• Endotherms

  Regulate their own body temperature through a nervous response

  • Peripheral temperature receptors in the skin detect a change in the external temperature.
  • This send an impulse along a sensory neuron to the brain, where the hypothalamus coordinates the impulse. This triggers a response by gland in the skin and muscles.

  Eg.

  Produce more sweat- water has a high latent heat of vaporiasation, as sweat evaporates a lot of heat from the skin is lost

  Vasoconstriction- restriction of arterioles near the skin surface mean less heat enery radiating from the skin