homeostasis

• what is homeostasis?

  maintaining a constant internal environment
• why do conditions in your body need to be kept steady?

  your cells need the right conditions in order to function properly, including the right conditions for enzyme action. It can be dangerous for your health if conditions vary too much from normal levels.
• how do you maintain a constant internal environment?

  your body needs to respond to both internal and external changes, whilst balancing inputs with outputs.
• what are examples of homeostasis?

  • osmoregulation (regulating of water content)
  • thermoregulation (regulating of body temperature)
  • blood glucose regulation
• how is osmoregulation an example of homeostasis?

  you need to keep a balance between the water you gain (in drink, food, and from respiration) and the water you pee, sweat, and breathe out.
• how is thermoregulation an example of homeostasis?

  you need to reduce your body temperature when you're hot, but increase it when the environment is cold.
• how is blood glucose regulation an example of homeostasis?

  you need to make sure the amount of glucose in your blood doesn't get too high or too low.
• how do negative feedback systems help to keep conditions in your body steady?

  if a condition changes away from the normal level, a response is triggered that counteracts the change.
• what is an example of how a negative feedback system helps to keep conditions in your body steady?

  A rise in blood glucose level causes a response that lowers blood glucose level.
• in terms of glucose, what does eating foods containing carbohydrates do?

  puts glucose into the blood from the small intenstine.
• what removes glucose from the blood?

  • the normal metabolism of cells removes glucose from the blood.
  • vigorous exercise removes much more glucose from the blood.
• how are excess glucose stored?

  as glycogen in the liver and in the muscles. When these stores are full, then the excess glucose is stored as lipid (fat) in the tissues.
• what are changes in the blood glucose monitored and controlled by?

  the pancreas, using the hormones insulin and glycogen.
• what is added when blood glucose concentration is too high?

  Insulin
• what is added when blood glucose concentration is too low?

  glucagon
• why do we need to regulate our body's internal conditions?

  to make sure our enzymes and cells function well.
• what happens if our body's conditions are not optimal?

  our enzymes may denature meaning their ability to catalyse metabolic reactions, is reduced.
• what are the conditions that need to be regulated?

  • water levels
  • carbon dioxide levels
  • urea concentration (in urine)
  • internal body temperature
  • blood sugar levels
• what are the purpose of effectors?

  (muscles or glands) carry our responses to stimuli that help to restore optimum levels.
• what is the purpose of receptors?

  detect changes in environment.
• what is the purpose of coordination centres?

  coordination centres recieve and process information arriving from receptor cells.
• what is a negative feedback system?

  when our internal conditions are optimal, the body does not ned to respond. If an internal conditions changes and is no longer optimal, the body works to counteract the change and return the conditions to optimum.