homeostasis

• Homeostasis


  Balancing body functions to maintain a "normal" state
• Conditions in your body need to be kept steady so that cells can function properly
• Homeostasis


  Balancing inputs (stuff going into your body) with outputs (stuff leaving)
• Conditions that need to be balanced

  • Water content
  • Body temperature
• Homeostasis is the maintenance of a constant internal environment
• Ways water is lost from the body

  • Through the skin as sweat
  • Via the lungs in breath
  • Via the kidneys in urine
• On a hot day or when you're exercising

  You sweat a lot, produce less urine which is more concentrated
• On a cold day or when you're not exercising


  You don't sweat much, produce more urine which is pale
• Body temperature


  • Enzymes work best at around 37°C
  • The brain acts as a thermostat to maintain this temperature
• Homeostasis happens automatically without you having to concentrate on it
• Skin's role in maintaining body temperature


  • Sweating to cool down
  • Blood vessels dilating to allow more heat loss
  • Hairs standing up to trap insulating air when cold
• Smaller organisms can cool down or heat up faster due to their higher surface area to volume ratio