What Is the Digestive System? The digestive system breaks down the food we eat into tiny parts to give us fuel and the nutrients we need to live. As food breaks down, we get amino acids from protein, ...

What Does the Heart Do? The heart is a pump, usually beating about 60 to 100 times per minute. With each heartbeat, the heart sends blood throughout our bodies, carrying oxygen to every cell. After ...

What Are the Lungs and Respiratory System? The lungs and respiratory system allow us to breathe. They bring oxygen into our bodies (called inspiration, or inhalation) and send carbon dioxide out ...

We see and hear about hearts everywhere. A long time ago, people even thought that their emotions came from their hearts, maybe because the heart beats faster when a person is scared or excited. Now ...

Allergic reactions can be triggered by foods, medicines, pets, insect stings, pollen, and other things. Most allergic reactions aren't serious. But severe reactions can be life-threatening and need ...

Which part of your body lets you read the back of a cereal box, check out a rainbow, and see a softball heading your way? Which part lets you cry when you're sad and makes tears to protect itself?

A cochlear implant is a surgically placed device that helps a person with severe hearing loss hear sounds. The cochlea is a snail-shaped part of the inner ear. It turns sound vibrations into ...

How much do you know about the urinary system, which makes pee? Find out by taking this quiz!

If you decide to have sex, it’s important to know about birth control so you can protect against unplanned pregnancy and sexually transmitted diseases (STDs). STDs are infections that can spread can ...

What Is the Respiratory System? When we breathe, the respiratory system takes in oxygen and sends out carbon dioxide. The cells in our bodies need fresh oxygen to stay alive. As cells do their jobs, ...

Your eyes see, but how does vision happen? Find out how the eyes and brain work together in this eye video.

What Is Athlete's Foot? Athlete's foot, or tinea pedis (say: TIN-ee-uh PEH-dus), is a common skin infection that is caused by a fungus (say: FUN-guss). This fungus eats old skin cells. And plenty of ...