If you've ever laced your fingers together, turned your palms away from you, bent your fingers back and heard a loud crack or pop, you know what knuckle-popping sounds like. So, what would happen if you popped your knuckles all the time?
The heart is a vital organ that basically serves as a pump. Learn about heart chambers and valves, blood flow, the heart's electrical system and blood supply. Read more about how this amazing organ works.