Homeostasis

• Homeostasis


  The regulation of the conditions inside your body (and cells) to maintain a stable internal environment, in response to changes in both internal and external conditions
• Homeostasis


  • The conditions inside your body need to be kept steady, even when the external environment changes
  • This is really important because your cells need the right conditions in order to function properly, including the right conditions for enzyme action
• Homeostasis


  1. Automatic control systems in your body that regulate your internal environment

  2. These include both nervous and hormonal communication systems

  3. Maintain body temperature

  4. Maintain blood glucose level

  5. Maintain water content
• Automatic control systems


  • Made up of three main components: cells called receptors, coordination centres (including the brain, spinal cord and pancreas), and effectors
• Negative feedback


  1. Receptor detects a stimulus (level is too high or too low)

  2. Coordination centre receives and processes the information, then organises a response

  3. Effector produces a response which counteracts the change and restores the optimum level
• Receptor detects a stimulus (level is too high)


  • Coordination centre receives and processes the information, then organises a response
  • Effector produces a response which counteracts the change and restores the optimum level
  • Level decreases
• Receptor detects a stimulus (level is too low)


  • Coordination centre receives and processes the information, then organises a response
  • Effector produces a response which counteracts the change and restores the optimum level
  • Level increases
• The effectors will just carry on producing the responses for as long as they're stimulated by the coordination centre. This might cause the opposite problem- making the level change too much (away from the ideal). Luckily the receptor detects if the level becomes too different and negative feedback starts again.