The lungs

• Lungs


  Vital parts that help to get the oxygen in, and the waste carbon dioxide out
• Lungs


  • Located in the thorax
  • Separated from the lower part of the body by the diaphragm
  • Big pink sponges protected by the ribcage
  • Surrounded by the pleural membranes
• Air flow


  1. Breathed in through the trachea

  2. Splits into two bronchi

  3. Bronchi split into smaller bronchioles

  4. Bronchioles end at alveoli
• Alveoli


  Small bags where gas exchange takes place
• Gas exchange in alveoli

  1. Oxygen diffuses from alveoli into blood

  2. Carbon dioxide diffuses from blood into alveoli
• Oxygen and carbon dioxide exchange in body cells

  1. Oxygen released from red blood cells into body cells

  2. Carbon dioxide diffuses from body cells into blood
• The lungs contain millions and millions of alveoli
• Blood passing next to the alveoli has just returned to the lungs from the rest of the body, so it contains lots of carbon dioxide and very little oxygen
• When the blood reaches body cells, oxygen is released from the red blood cells (where there's a high concentration) and diffuses into the body cells (where the concentration is low)
• Carbon dioxide diffuses out of the body cells (where there's a high concentration) into the blood (where there's a low concentration)
• Breathing rate is the number of breaths per minute