Does anyone know of one online? I'm trying to learn more in depth the structure of the lungs. I'm pretty confused about where the air actually exits the trachea / bronchioles to fill up the lungs.... If that's even how it works. I want to find out what actually makes the chest rise? Are the lungs sort of like a bag of air and the bronchioles floating inside it with the vessels around the alveloi for gas exchange? Or how does it work? The A&P book doesn't really go into this type of structure and I'm confused.