(cont'd from yesterday's post)
One thing that could go wrong in our bodies would be a failure of sufficient oxygen to get to our living cells. Every one of them (30 trillion cells) needs a supply of oxygen every minute. Our bodies store water and fat, but not oxygen.
Muscles pull oxygen (O2) from outside the body into the lungs. Molecules of O2 diffuse into blood vessels at a limited speed.
To maximize how much O2 can get through blood vessel membranes and into the blood, each lung's little air sacs are surrounded with tiny blood vessels. There are so many that the total membrane area of all the blood vessels together amounts to the size of a tennis court. The video pictures it for you.
Engineering--not magic--gets the job done.
We'll come back to these videos of the body's engineering design in a future week. Tomorrow . . design in the honeybee.
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