Biology - Homeostasis and Response - Homeostasis

• How is this ensured

  • Our body regulates everything making sure everything is around the right levels
  • Don't keep everything constant (temperature and glucose levels do fluctuate within small bounds)
• Define the term homeostasis

  The regulation of conditions inside the body to maintain a stable internal environment, in response to both internal and external conditions
• List things the body just regulate during homeostasis

  • Too hot
  • Too cold
  • Too acidic
  • Top alkaline
  • Glucose levels
  • Water levels
• What does regulating internal conditions due to external conditions mean

  Maintain internal environment even if changes are taken place outside of our cells (if in snow or desert we can still keep our cells at 37 degrees by regulating our body)
• How does our body do this

  Automatic control
• Define the term automatic control

  Recognise change from optimal conditions and send a signal to reverse the change so the levels go back to normal
• List the three automatic control systems

  • Receptors (detect a change such as a rise in temperatures)
  • Coordination centres (such as brain or spinal chord which interpret the change deciding what needs to be done)
  • Effectors (carry out the change such as muscles that contract or glands that release hormones)
• What does the nervous system to

  Send very fast and precise electrical impulses through nerves which respond very quickly
• What does the endocrine system do

  Small hormones which are released and travel through the bloodstream and body but only effect certain cells with the right receptors
• What's the difference between the nervous and endocrine system

  The endocrine system is slower, longer lasting and more generalized
• Define the term negative feedback

  When the level of something too high (glucose in our blood) negative feedback acts to decrease it and return it to normal, if negative feedback decreases it too low then it will increase it again
• Explain an example

  • Walk into a cold room
  • Temperature will be detected by receptors (skin)
  • Nervous system sends impulses to coordination centers (brain or spinal chord)
  • These interpret this information and send more signals to effectors (muscles which carry out useful responses such as shivering)
  • Over time the shivering will increase our body temperature back to normal
  • If we get too hot, a different set of receptors detect the temperature and send own signals to coordination centre
  • Causing a different group of effectors to carry out their own response (sweating)