Homeostasis

• What is homeostasis

  Maintaining a constant internal environment
• Why do conditions in the body need to be kept constant

  • as cells need right conditions to function properly
• what happens if the internal conditions vary too much

  serious health issues
• what must the body do to maintain the body's internal environment

  body must respond to internal + external changes
• what is thermoregulation

  maintaining a constant internal body temperature
• why is thermoregulation important

  • as many chemical reactions in body are enzyme controlled
• what happens if the temperature is not kept constant

  • if too cold -> enzymes may not function QUICK enough
  • if too hot -> denature
• what is osmoregulation

  maintaining a constant water concentration
• why is osmoregulation important

  so our cells function properly
• what happens if the water concentration is too high in the blood

  • cells will take in water by osmosis
  • if too much water taken in -> cells may burst (lysis)
• what happens if the water concentration is too low in the blood

  • water will move out of the cells by osmosis
  • if too much water leaves -> cells may shrink
• what is blood glucose regulation

  • process in which levels of blood sugar (common name for glucose dissolved in blood plasma) are maintained
• what happens if there isn't enough glucose in the blood

  cells won't be able to respire properly
• what happens if there is too much blood glucose

  be stored as fat and contribute to obesity
• what are the 3 regulations our body does for homeostasis to happen

  • thermoregulation
  • osmoregulation
  • blood glucose regulation
• what are most types of homeostasis controlled by

  a process called negative feedback
• what is negative feedback

  when conditions change from ideal point and so are their returned to this set point in response to external changes
• in negative feedback what happens if the level of smth rises

  control systems switched on to REDUCE it again
• in negative feedback what happens when the level of smth falls

  control system switched on to RAISE it again
• why is negative feedback mechanisms described as a continuous cycle

  • brings levels down and back up
  • so overall they stay within a narrow range of what is considered 'normal'
• describe hormones

  • slow acting
  • long acting (effects last longer)
  • act in a general way
• describe neurones

  • fast actions
  • short actions
  • acts in a specific area