Physiotherapy Question:

Yup. About 20 times a minute, you breathe in. When you do,
you inhale air and pass it through your nasal passages
where the air is filtered, heated, moistened and enters the
back of the throat. Interestingly enough, it's the
esophagus or foodpipe which is located at the back of the
throat and the windpipe for air which is located at the
front. When we eat, a flap -- the epiglottis -- flops down
to cover the windpipe so that food doesn't go down the
windpipe.

So -- back to breathing -- the air has a long journey to
get to your lungs. It flows down through the windpipe, past
the voice box or vocal cords, to where the lowermost ribs
meet the center of your chest. There, your windpipe divides
into two tubes which lead to the two lungs which fill most
of your ribcage. Inside each of your sponge-like lungs,
tubes, called bronchi, branch into even smaller tubes much
like the branches of a tree. At the end of these tubes are
millions of tiny bubbles or sacs called aleoli. Spread out
flat, all the air sacs in the lungs of an adult would cover
an area about the third of a tennis court.