Pulmonary hypertension is high blood pressure in the pulmonary arteries.
It heart is a contracting muscle that pumps oxygenated blood to all parts of the body. After the blood has left the heart, it must first pass through the lungs to ‘load up’ oxygen for cells in the rest of the body.
On the way from the heart to the lungs the blood travels through the pulmonary artery, and then through a network of smaller and smaller pulmonary blood vessels. The diameter of these vessels is regulated by endothelin, a hormone that travels with the bloodstream.
The pulmonary condition hypertension characterized by a strong increase in the amount of endothelin in the bloodstream. This high endothelin content narrows the small pulmonary arteries. As the pulmonary arteries narrow, the resistance of the blood to flow increases, forcing the heart to exert more effort to pump blood to the lungs. And at the same time, the lungs have to work harder to transfer enough oxygen into the blood.
This condition causes blood pressure in the pulmonary arteries to become abnormally high. Because the heart has to expend more energy pumping blood, the right side of the heart can grow abnormally and heart failure originate.
