Question: What is the most remarcible body structure you have researched?

Mark Burnley answered on 14 Jun 2011:

The lungs, I think. They have to transfer oxygen and carbon dioxide to and from the blood, and protect you from infections. Deep down inside them, they are only 2 cells thick (the alveolar membrane and the capillary membrane, but must be able to withstand the in- and out-rushing of air and all of the blood that leaves the right side of the heart. To do this without breaking, the proteins in the alveolar walls are arranged like chicken-wire, making them very thin but also very strong. And if you think that’s clever, take a look at the lungs of birds, which are absolutely AMAZING.