Your heart has four valves. normally, these valves open to let blood flow through your heart, and then shut to keep it from flowing backward. sometimes the valves don't work properly, causing some or all of the following disorders. in regurgitation, blood leaks back through the valve in the wrong direction. in valve prolapse, the valves have "floppy" flaps and don't close tightly. it's one of the most common heart valve conditions. sometimes it causes regurgitation. in stenosis, the valve doesn't open enough and blocks blood flow. based on your knowledge of the heart, explain how regurgitation, valve prolapse, and stenosis each adversely affects blood flow and the oxygenation of body tissues.