Aortic valve donation (image 1 of 3). Gloved hand of a surgeon dissecting a donated human heart to remove the aortic valve. The aortic valve (white, at centre) lies between the left ventricle (main pumping chamber) of the heart and the aorta, the body's largest artery. Its function is to allow blood to flow out of the chamber but to prevent backwash. The valve can be donated and transplanted into patients whose own valve is malfunctioning due to disease. (See photo number M560/246 for a picture of the dissected aortic valve, and M560/247 for the valve packaged for storage.)