To better understand pneumoconiosis, it helps to understand the anatomy of the lungs.
Inside the chest, the windpipe, or trachea, divides into two smaller tubes: the right bronchus and the left bronchus. The right bronchus enters the right lung and the left bronchus enters the left lung. The right bronchus and left bronchus branch into smaller and smaller tubes.
The smallest tubes, called bronchioles, end in tiny air sacs, called alveoli. Blood flows very close to the walls of the alveoli. Oxygen and carbon dioxide pass between the air and the bloodstream through the wall of the alveoli.
- Centers for Disease Control and Prevention (CDC). Changing patterns of pneumoconiosis mortality--United States, 1968-2000. MMWR Morb Mortal Wkly Rep. 2004 Jul 23;53(28):627-32. 
- Fujimura N. Pathology and pathophysiology of pneumoconiosis. Curr Opin Pulm Med. 2000 Mar;6(2):140-4. 
- Pham QT. Chest radiography in the diagnosis of pneumoconiosis. Int J Tuberc Lung Dis. 2001 May;5(5):478-82.