Powerful Pump

In under a minute, your heart can pump blood to every cell in your body. And over the course of a day, about 100,000 heart beats shuttle 2,000 gallons of oxygen-rich blood many times through about 60,000 miles of branching blood vessels that link together the cells of our organs and body parts. That's a hefty job for a fist-sized muscle.

Heart Mend

A love-torn heart can be painful enough to make you wish you could get a new heart or at least a cardio repair kit. Both of the latter options could some day be realities. Scientists are studying the red-spotted newt to help them develop cell therapies for humans with physically damaged hearts. This amphibian can turn its cells back in time, as if they were stem cells, in order to build up new heart muscle. In another study, scientists engineered a beating heart from embryonic stem cells in the lab.

LOL: It's Good for You

A hearty laugh e the kind that sends a stream of tears from your eyes e does more than warm the soul. Research has shown the guffaw can cause the lining of blood vessel walls called endothelium to relax, increasing blood flow for up to 45 minutes after the laugh attack. Damage to the endothelium can lead to the narrowing of blood vessels and eventually cardiovascular diseases. That's no laughing matter...or maybe it is...