Human Body

The human body is an amazing structure made up of many fascinating parts and systems. Learn about the human body and how its systems work together.


Ever wondered how your stomach acid knows the difference between your stomach and the food inside it?

Millions of people have refractive vision problems -- when the eyes get blurry or can't focus on an object. Learn about four major types of refractive vision problems.

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?

We all know 20/20 vision is a good thing, but just what do those numbers mean?

Lymph is a commonly-used medical term, but what's it mean exactly?

Your appendix is really a pretty mysterious organ. Find out why you have an organ that's not necessary to your survival.

Your ears are very sensitive to the air or water pressure around them. But just what happens when you dive into that pool?

You may never have thought about it (unless your child asks), but boogers are sticky for a perfectly logical scientific reason.

You breath all day, every day. How much oxygen does this process consume?

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.

There are millions of bacteria, microbes, viruses, toxins and parasites that want to invade your body. And they'd happily do it, too -- if it weren't for your immune system.