Body Systems

Your body is pretty amazing. At any given point you have many biological processes going on -- circulatory, digestive, brain & central nervous systems and more. Learn about these body systems as well as the eye, ears, nose and throat.


The nervous system is a complex network of specialized tissues that regulates thoughts, emotions, actions, sensations, and body functions. It has two major divisions: the central nervous system and the peripheral nervous system.

The endocrine system comprises a number of glands that produce hormones with a varied array of vital functions. Hormones control or regulate the development or function of structures throughout the body.

Healthy digestion involves the whole body. Learn about the processes and body parts that go into digestion.

The heart is one of the strongest muscles in the body. Learn about this extremely vital part of the body.

Muscles are one of those things that most of us take completely for granted, but they're the body's engine. Without our muscles, we couldn't walk or talk -- and our blood would stop flowing.

When you donate blood, your blood type is an important factor in how useful your donation may be. Just what are blood types?

The kidneys spend 24 hours a day, seven days a week filtering gallons and gallons of blood. But that's not all these little bean-shaped organs accomplish in a day.

You breathe in and out anywhere from 15 to 25 times per minute without even thinking about it -- it just happens naturally. Learn all about your lungs, various conditions and diseases, and what makes the breath of life so crucial.

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 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.