Homeostasis

• Homeostasis


  A condition of equilibrium (stability or balance) in the body's internal environment
• Homeostasis


  • It is dynamic
  • Constant fluctuations of both the internal and external environment
  • Internal conditions usually vary within a very narrow range
  • All body systems contribute to homeostasis
  • The nervous and endocrine systems are the most important
• Basic control systems of homeostasis

  1. Stimulus

  2. Sensor/receptor

  3. Integrator/control centre

  4. Effector (and response)

  5. Feedback
• Negative feedback


  • Inhibitory, therefore negates change
  • Prevent sudden severe changes within the body; reverses or negates original stimulus
  • Once equilibrium is achieved the response is reduced and the process "shut off"
  • More common
• Positive feedback


  • Do not help to maintain equilibrium
  • Do not oppose a change in internal environment
  • Enhance and amplifies the effector so the response continues at a faster rate
  • Only stops when stimulus removed
  • Less common
• Homeostasis is a condition of equilibrium (stability or balance) in the body's internal environment