Giant Microbes Cells at Work Red Blood Cell
Although erythrocytes are flexible (which permits them to squeeze through capillaries), they typically have a distinctive biconcave shape that helps maximise surface area to facilitate the exchange of gases.
A normal person can have more than 10,000,000,000,000 erythrocytes in their body! So don't fret if a few escape. And think about giving some away too. Donated blood can only be stored for six weeks and is constantly required to save the lives of accident victims and surgical patients, and to help manage chronic diseases. If you're healthy, you've got lots to spare. So have a heart - it's a bloody good idea!