Secondary Pulmonary Hypertension Anatomy
To better understand pulmonary hypertension, 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.
- Lee SH, Rubin LJ. Current treatment strategies for pulmonary arterial hypertension. J Intern Med. 2005 Sep;258(3):199-215. 
- McCrory DC, Lewis SZ. Methodology and grading for pulmonary hypertension evidence review and guideline development. Chest. 2004 Jul;126(1 Suppl):11S-13S. 
- Randall PA, Heitzman ER, Bull MJ, Scalzetti EM, Williams SK, Gordon LP, Markarian B. Pulmonary arterial hypertension: a contemporary review. Radiographics. 1989 Sep;9(5):905-27.