Communication and Homeostasis

• what is homeostasis?


  the maintenance of a constant internal environment via physiological control systems
• what does homeostasis control?

  keeping body temperature up, blood pH, blood glucose and blood water potential
• what is negative feedback?

  when there is a deviation from the set limits is detected in the body by a receptor mechanisms are put in place to restore the conditions back withing the set limits

  • involves nervous system and hormones
• what is positive feedback?


  when a deviation from the set limits triggers a response to increase the deviation further
• when can positive feedback occur?

  childbirth when babies head presses on cervix oxytocin is released causing uterus to contract
• what is thermoregulation?


  The process of maintaining a stable internal body temperature.

  • if the body temp increased too high enzymes would denature
• what are ectotherms?


  Animals that rely on external sources of heat to regulate their body temperature.
• what are endotherms?


  Animals that generate heat internally to maintain a constant body temperature.
• how do endotherms cool there body?

  • produce more sweat
  • vasodilation (blood flows nearer the skin)
  • vasocontraction (blood flows further away)
  • shivering
• what regulates the body temperature in ectotherms?

  peripheral temperature receptors in skin that detect change through sensory neurone connected to the hypothalamus