Functioning Organisms

• Why do we breathe

  To replace CO2 with oxygen
• Cellular respiration formula


  Glucose + oxygen - carbon dioxide + water
• Air passage


  • nose/mouth
  • pharynx
  • trachea
  • bronchus
  • bronchiole
  • alveoli
• Where does the diaphragm sit

  Under lungs
• Function of rings of cartilage around trachea

  Keep trachea open and prevent it from collapsing when empty
• What is the trachea


  A large tube that connects the throat to lungs
• Trachea function


  Carries air in and out of lungs
• What is the epiglottis

  A flap made of tissue that prevents food from entering the trachea
• What are the bronchi

  Tubes that connect trachea to lungs
• What are the bronchioles

  Smaller tubes that branch bronchi to lungs
• What are the alveoli


  Air filled sacs in the lungs where gas exchange takes place
• What happens in the gas exchange

  Oxygen diffuses into blood, CO2 diffuses out via capillaries
• What is cilia


  Tiny hairs that line the bronchi and trachea to push mucus up into mouth
• Why does the cilia push mucus up into the mouth

  So it can be swallowed and destroyed by stomach acid
• What are goblet cells

  Mucus that traps dirt and bacteria before entering the lungs
• Where are goblet cells

  In between cilia
• The alveoli are surrounded by

  Capillaries
• Where does air diffuse into and from

  Capillaries
• Why do alveoli have thin walls

  So gas can diffuse quickly between lungs and blood
• High concentration of oxygen in alveoli


  Diffuses into blood that has low oxygen concentration
• High concentration of carbon dioxide

  Diffuses into alveoli that has a low CO2 concentration
• Oxygen travels in


  Blood
• CO2 travels in


  Liquid part
• Asthma is the


  Narrowing of airways
• Why do the airways narrow

  Contracting muscles, swollen lining or too much mucus produced in the airways
• What does the circulatory transport

  Dissolved glucose and oxygen