Maciej Staszkiewicz
Maciej Staszkiewicz voted up Enigmos Realdi's answer

Our respiratory system is like an upside down tree. Our Bronchi divide into bronchioles, which end up in small air sacs called alveoli, which are surrounded by a large network of capillaries. The deoxygenated blood enters the capillaries and inhaled air fills alveoli, and oxgen and carbon dioxide exchange between the duo through a wall … Read more