Homeostasis

• Homeostasis


  The maintenance of a constant internal environment
• Homeostasis


  • Any process organisms use to maintain the stable conditions necessary for survival
• Maintaining blood glucose concentration

  1. Pancreas secretes insulin

  2. Insulin stimulates liver to remove glucose from blood

  3. Brings levels back to normal range
• Negative feedback


  A process that maintains a stable internal environment by reversing any changes that occur from the set point
• Factor deviates from set point


  Change is detected and negative feedback loop is activated to return it
• Set point


  Ideal value or narrow range of values for a given factor
• Controlling blood glucose levels

  1. Higher glucose detected

  2. Pancreas secretes insulin

  3. Insulin stimulates liver to remove excess glucose

  4. Converts to glycogen for storage
• Controlling blood glucose levels during exercise

  1. Blood glucose falls

  2. Pancreas secretes glucagon

  3. Glucagon stimulates liver to break down glycogen into glucose

  4. Glucose enters bloodstream
• Type 1 diabetes


  Chronic condition characterized by inability to regulate blood glucose due to lack of insulin production
• Treatment of type 1 diabetes

  1. Regularly monitor blood

  2. Inject insulin when levels too high

  3. Maintain healthy diet

  4. Exercise to reduce blood glucose
• Maintaining constant internal body temperature

  • Essential for enzymes to function properly
  • Thermoreceptors detect changes
  • Brain processes and sends impulses to effectors
• Thermoregulatory mechanisms in cold conditions

  1. Fatty tissue insulates

  2. Hair erector muscles contract to trap air layer
• Thermoregulatory mechanisms in hot conditions

  1. Hair erector muscles relax to promote air circulation

  2. Sweat glands secrete sweat which evaporates to cool body
• Regulating body temperature through blood vessels

  1. Arterioles vasodilate in heat to increase blood flow and heat loss

  2. Arterioles vasoconstrict in cold to reduce blood flow and heat loss