Your genes or other medical conditions can cause pulmonary hypertension. Certain medical conditions can damage, change, or block the blood vessels of the pulmonary arteries. The cause of pulmonary hypertension is not always clear.

To understand pulmonary hypertension, it is helpful to understand the flow of blood through the heart and lungs. The right side of your heart receives oxygen-poor blood from your body’s tissues. The pulmonary arteries connect your right heart and lungs. The heart pumps blood through the pulmonary arteries to the lungs to become oxygen-rich blood. The force or pressure of the blood against the walls of the pulmonary arteries is called the pulmonary pressure.

To learn more, visit How the Lungs Work and How the Heart Works.