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.

Topics to Explore


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Why do a child's bones heal faster than an adult's?

Oh, to be a kid again. Plenty of summer vacation, plenty of mud puddles and plenty of osteoblasts? There's a reason your kid can spring back from any injury while you're laid up for weeks.

Why does it take my eyes several minutes to adjust to darkness?

At night, your eyes adjust to darkness after several minutes. Do you know why it takes that long? Take a look at how your eyes adjust to darkness.

Exactly why is your thyroid so important?

Chances are rather good you've heard the news that you have a thyroid -- but chances are also pretty decent you're not completely up to speed on exactly why you have one. What can your thyroid do for you?

Why do humans have body hair?

By waxing, shaving, plucking and shearing, we manage to keep unwanted hairs at bay. But considering how much you shell out for new razors and your trips to the salon, it's a wonder that we bend over backward to groom a bunch of dead cells.

Can brain foods make you smarter?

Instead of just giving in to your food cravings, how about nourishing your brain? Take a look at the foods that kick-start your smarts. Here's a hint -- that candy bowl's not going to help.

How and why does the heart pump blood to itself?

Every second of the day, blood bustles through your body, bound for your brain, toes and everything in between. How does your heart receive its fair share of the good stuff?

What determines the rhythm of your heart?

When it comes to the heart, timing is critical. An irregular heartbeat is inefficient and deprives the body of blood. So what sets your ticker's rhythm?

What causes the sound of a heartbeat?

Lub-dub, lub-dub, lub-dub, that's usually the sound of a happy heart. But what's responsible for that steady, comforting beat, and what if your heart doesn't sound like that?

How does the body make electricity -- and how does it use it?

Everything we do is controlled and enabled by electrical signals running through our bodies. But how are those signals produced, and what happens when your electrical system breaks down?

Heart Pictures

The heart is crucial to life and the focus of love. Explore the parts of the heart and how your heart works, plus take a look at real pictures of human hearts with this gallery.

Bodily Organ Pictures

Have you ever wondered what your body looks like on the inside? Take a tour of your major bodily organs and learn about unusual organ conditions with these pictures.

Brain Teasers and Mind Games

A healthy brain works better longer, keeping memory accurate and thought processes clear. Learn more about the benefits and options of brain teasers and mind games on your health.

5 Memory Boosters

Although most people accept that some memory loss occurs with aging, it is also possible to take proactive steps to protect memory. Take a look at what we have uncovered about reversing the effects of memory loss with these 10 tips.

The Brain and Mental Health

The brain is a complex grouping of nerve cells and other structures that help us think, react to the environment, make decisions and carry them out. Take an in depth look into one of the most interesting parts of the human body.

Fantastic Facts about the Human Body

The human body is fantastic biological specimen. Learn more about the human body with these revealing and insightful facts.

How Vestigial Organs Work

Vestigial organs are like the contents of your junk drawer: an assortment of objects that once had a purpose or might come in handy. What can these evolutionary mementos tell us?

How can someone be born with organs outside the body?

It happens more often than you may think. Sometimes a baby is born with organs outside of his or her body and has a slim chance of survival. What causes this?

Why are some people born with a reversal of organs?

Most people's organs follow the same basic layout -- heart on the left, appendix on the right and stomach in the middle. But in about 1 in 10,000 births, organs end up on the opposite side.

Brain Pictures

What does your brain really look like? It depends on how it's imaged. Take a look at all the different ways we can view the human brain.

How Your Appendix Works

Does the appendix serve any purpose in the human body? Scientists are divided on the issue -- learn why.

How do broken bones heal?

Unfortunately for him, Humpty Dumpty was not blessed with the human skeletal system. Why can your skeleton do what all the king's horses and all the king's men can't?

How Osteogenesis Imperfecta Works

How could a high-five or a handshake lead to a wrist fracture? People with osteogenesis imperfecta must carefully consider these seemingly innocent actions to prevent broken bones.

Why does my stomach growl?

Whether you call it grumbling, gurgling or growling, sometimes your belly just won't keep quiet. What makes your stomach growl, and why does it seem to happen at the worst times?

Serum Creatinine Overview

Creatinine is a chemical molecule that is present in the serum (liquid portion) of the blood. The amount of creatinine produced depends on a person's muscle mass. But how is it measured?

What if I crossed my eyes for 10 minutes?

"Don't cross your eyes -- they'll stick that way!" That's something most of us have heard from our mothers at one time or another. Can your eyes really get stuck?