Heart, Section Through the Middle

The interior of the heart is composed of valves, chambers, and associated vessels.

Heart, Front View

The external structures of the heart include the ventricles, atria, arteries and veins. Arteries carry blood away from the heart while veins carry blood into the heart. The vessels colored blue indicate the transport of blood with relatively low content of oxygen and high content of carbon dioxide. The vessels colored red indicate the transport of blood with relatively high content of oxygen and low content of carbon dioxide.

Transposition of the Great Vessels

Transposition of the great vessels is a congenital heart defect in which the position of the two major vessels that carry blood away from the heart - the aorta and the pulmonary artery - is switched (transposed). This defect is classified as a cyanotic heart defect because the condition results in insufficiently oxygenated blood pumped to the body which leads to cyanosis (a bluish-purple coloration to the skin) and shortness of breath.