interesting facts things about respiratory system

Each lung contains 300-350 million respiratory units called alveoli making it a total of 700 million in both lungs. More than half a liter of water per day is lost through breathing.
We breathe 13 pints of air every minute. People under 30 years of age take in double the amount of oxygen in comparison to a 80 year old.

High Elevation Respiration

High Elevation Respiration video videos..
At higher elevations, the respiratory system has to work harder to pull in the amount of oxygen necessary for survival from the environment. To watch the video click here or go to : http://videos.howstuffworks.com/hsw/12117-investigating-human-biology-high-elevation-respiration-video.htm