Homeostasis

• Homeostasis is the process of maintaining a constant internal environment despite changing external conditions
• Ensures that the organs of the body operate within their normal limits thereby working efficiently
• Based on a feedback system
• Information is sent to a control center which directs the organ to react accordingly
• Two major control centers:
  1.     Brain of the nervous system
  2.     Glands of the endocrine system
  Several factors must be regulated including:
  1.     Temperature
  2.     Heart rate
  3.     Respiratory rate
  4.     Blood pressure
  5.     Water balance
  6.     Blood sugar levels.
  7.  Detoxification
  
  
  
  

  Activity	Organs involved	Center of Control
  Temperature	Skin	Hypothalamus
  Heart rate	Heart	Medulla oblongata
  Respiration rate	Ribs & diaphragm	Medulla oblongata
  Blood pressure	Heart and arteries Kidneys	Medulla oblongata controls: -cardiac output -arteriole resistance Hypothalamus directs the pituitary gland of the endocrine system to control water levels in the blood
  Water balance	Kidneys	See above
  Blood sugar levels	Pancreas (enzyme pancrease)	Islets of Langerhans control sugar levels: Insulin – reduces blood sugar levels Glucagon – increases blood sugar levels
  Detoxification	Liver	Removes harmful substances from the blood and inactivates them, returning them to the blood to be removed by the kidneys