The Lungs

• The Lungs are in the thorax (top part of the body)
• Separated from the lower part of the body by the diaphragm
• The lungs are like a sponge and are protected by the ribcage.
• Air that is breathed in go through through a trachea. Splits into two tubes called bronchi (each one is a bronchus), one going to each lung
• The bronchi split into progressively smaller tubes called bronchioles
• Bronchioles finally end at small bags called alveoli where gas exchange takes place
• The lungs contain millions and millions of air sacs called alveoli, surrounded by a network of blood capillaries. This is where gas exchange takes place
• Blood passing next to the alveoli just returned to the lungs from the rest of the body,so contains lots of Carbon dioxide and very little oxygen. Oxygen diffuses out of the alveolus into the blood (high to low concentration) co2 diffuses from the blood into the alveolus (low to high concentration) to be breathed out
• When the blood reaches body cells oxygen is released from the red blood cells (high concentration) and diffuses into the body cells (low concentration) At the same time co2 diffuses out of the body cells into the blood. Its then carried back to the lungs