lungs

• The lungs are in the thorax
• thorax is the top half of the body and is separated from the lower part by the diaphragm
• lungs are like big pink sponges protected by the rib-cage and are surrounded by pleural membranes
• Air goes through the trachea and splits into two tubes called bronchi
• Bronchi splits into progressively smaller tubes called bronchioles
• The bronchioles finally end at small bags called the alveoli where gas exchange happens
• Alveoli carries out gas exchange
• lungs contain millions of little air sacs called alveoli which are surrounded by a network of capillaries
• blood passing from the alveoli to the lungs contains a lot of carbon dioxide and very little oxygen
• oxygen diffuses out of the alveoli into the bloodstream and carbon dioxide diffuses into the alveoli
• when the blood reaches body cells oxygen is released from the red blood cells and diffuses into the body cells
• carbon dioxide diffuses out the body cell into blood then carried back out into the lungs