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 ...

Heavy metals are elements that are found in soil, water, and the air we breathe. Plants take up these metals as they grow and can end up in the food we eat. Our bodies need some heavy metals (like ...

How Does Air Enter the Respiratory System? Air enters the respiratory system through the nose or the mouth. If it goes in the nostrils (also called nares), the air is warmed and humidified. Tiny hairs ...

It’s normal for people to masturbate (touch or rub their own genitals because they like the way it feels). Some people do it to relieve stress or tension. It’s nothing to be ashamed of or embarrassed ...

Is it Safe to Use Household Chemicals During Pregnancy? Some household cleaners and chemicals are safe to use during pregnancy while others are not. Chemicals like ammonia and chlorine might cause ...

Sexually transmitted diseases (STDs) are infections spread from person to person during sex (vaginal, oral, or anal) or close sexual contact. STDs are also called sexually transmitted infections, or ...

Why are my breasts different sizes? Is there anything I can do about it? It is normal to have different sized breasts. If you have just started developing breasts, one breast may grow more quickly ...

How much do you know about your bones? Find out by taking this quiz!

infection in the urinary tract irritation or injury of the genital area stones (small masses of minerals) in the urinary tract Urinary tract infections (UTIs) are the most common cause of pain during ...

Carbohydrates (car-bo-HI-drates), often called carbs, are one of the three main nutrients in food (along with fat and protein). The body breaks carbohydrates down into sugars — the major source of ...

From your nose to your toes, do you know how the body works? Take these quizzes to find out!

How much do you know about your brain? Find out by taking this quiz!