June Gallery

1989 United States GP

STREETS OF PHOENIX, UNITED STATES OF AMERICA - JUNE 04: Stefan Johansson, Onyx ORE-1 Ford during the United States GP at Streets of Phoenix on June 04, 1989 in Streets of Phoenix, United States of America. (Photo by Ercole Colombo / Studio Colombo)

© Motorsport Images

F1, Formula 1, Gp, Helmet, Portrait

Artificial heart valve

False-colour angiogram (X-ray image) of the human heart, showing a mechanical Starr-Edwards aortic heart valve. A normal aortic valve regulates the flow of blood from the left ventricle into the aorta, the body's main artery, for distribution around the circulation. The valve consists of three cusps, shaped like half-moons. Malfunctions of the valve include fusion of the cusps, often the result of the scarring that follows rheumatic fever. This results in a narrowing of the valve's opening (aortic stenosis) with a consequent reduction in blood flow. An incompetent aortic valve may also cause blood to reflux back into the left ventricle (aortic regurgitation)

© SCIENCE PHOTO LIBRARY