Homeostasis

• Homeostasis


  A state of balance in the body
• Homeostasis


  • Maintaining blood pH within a certain range
  • Maintaining blood glucose within a certain range
  • Maintaining internal body temperature within a certain range
• Positive feedback


  When a variable is intensified instead of counteracted
• Positive feedback


  • Human baby being born - pressure on the cervix causes contractions which cause more pressure and hormones, intensifying the process
• Negative feedback


  When a variable triggers a counteracting response to return to a set point
• Negative feedback


  • Body temperature regulation - sweating and blood vessel dilation when too hot, shivering and blood vessel constriction when too cold, to maintain a stable temperature
• Negative feedback


  • Blood glucose regulation - insulin released when glucose is high, glucagon released when glucose is low, to maintain stable blood glucose levels
• Understanding feedback is important to understand what happens when there are problems in the feedback systems, such as in Type 1 diabetes where the negative feedback for insulin and glucose does not work correctly
• Homeostasis


  Constant internal environment maintained by automatic responses
• Homeostasis


  • Automatic responses
  • Maintain constant internal environment
• Homeostatic mechanism


  • Leaf fall to survive periods of low sunlight
• Negative feedback loop


  Mechanism that counteracts a change as set point is reached
• Sweating


  A homeostatic response to being hot
• Thermoregulation


  Process to maintain body's internal temperature at its set point
• Normal range


  Values within which an organism is experiencing healthy conditions
• Steady state


  A way of describing homeostasis and the conditions achieved by the mechanisms involved
• Receptors


  Responsible for detecting change in conditions