The heart is the body's hardest-working muscle. Whether you're awake or asleep, or exercising or resting, your heart is always at work. It pumps blood through arteries to deliver oxygen to organs and ...

Take an incredible journey inside the human body and discover how your brain, heart, blood vessels, red blood cells, and immune system work together every second. Discover how oxygen travels through ...

The adult heart may be trying to repair itself after a heart attack—it just struggles to finish the job. For decades, the adult heart was treated as an organ with almost no ability to replace the ...