The lungs

• What is the primary function of the lungs?

  The primary function of the lungs is to facilitate gas exchange, getting oxygen into the bloodstream and removing carbon dioxide.
• Why is it necessary to get oxygen into the bloodstream?

  It is necessary to supply cells for respiration.
• What is the thorax?

  • The thorax is the top part of the body.
  • It is separated from the lower part of the body by the diaphragm.
• What protects the lungs?

  The lungs are protected by the rib cage.
• What surrounds the lungs?

  The lungs are surrounded by pleural membranes.
• What is the pathway of air into the lungs?

  The air you breathe in goes through the trachea, which splits into two bronchi.
• What are the two tubes called that the trachea splits into?

  The two tubes are called bronchi.
• What do bronchi split into?

  Bronchi split into progressively smaller tubes called bronchioles.
• Where do bronchioles end?

  Bronchioles end at small bags called alveoli.
• What is the role of alveoli in the lungs?

  • Alveoli are small air sacs where gas exchange occurs.
  • They are surrounded by a network of blood capillaries.
• What type of blood is passing next to the alveoli?

  The blood passing next to the alveoli has just returned from the body, containing lots of carbon dioxide and very little oxygen.
• How does oxygen move during gas exchange in the alveoli?

  Oxygen diffuses out of the alveolus (high concentration) into the blood (low concentration).
• How does carbon dioxide move during gas exchange in the alveoli?

  Carbon dioxide diffuses out of the blood (high concentration) into the alveolus (low concentration).
• What happens to oxygen when blood reaches body cells?

  Oxygen is released from the red blood cells and diffuses into the body cells.
• How does carbon dioxide move from body cells to the blood?

  Carbon dioxide diffuses out of the body cells into the blood.
• What happens to carbon dioxide after it diffuses into the blood?

  Carbon dioxide is carried back to the lungs.