homeostasis

• • Negative feedback control:
  • Any movement away from a base level 
  • Automatic corrective mechanisms restore the base level 
  • when a change triggers a response that reduces the effect of that change
• homeostasis -

  • Maintaining a constant internal environment despite changes in external environment 
  • Involves constant monitoring (eg chemo and baroreceptors) and correcting of certain parameters before they cause damage to the body 
• positive feedback:

  when an initial change is increased further, pushing conditions further away from the base level
• system of negative feedback:

  • A change in a factor away from the optimum/base level
  • the change is detected by a receptor and hormones are released  OR  nerve impulses are sent 
  • hormone/impulse reaches target
  • effector performs corrective action
  • factor returns to the optimum/ base level
• Homeostasis ensures that fluctuations of internal conditions are kept within narrow limits