Lungs produce more than half of the platelets in the blood.

A good starting point for any scientist in any field is to recognize that there is much we do not know. We do not know, for example, why there is more matter than antimatter in the universe. We do not know very well how the evolution of the dinosaurs filtered out. And, perhaps most surprising of all is that we do not know very well how many organs the human body has or what all its functions are.