¿Qué hacen los cartílagos de crecimiento? Los cartílagos de crecimiento son una de las formas en las que crecen los huesos. En general, cada hueso largo tiene dos cartílagos de crecimiento. Estos ...

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 ...

Back pain is common, even in kids and teens. It can happen anywhere along the back, and might be a dull ache, a crampy feeling, or a sharp, shooting pain. Back pain often is caused by muscle strain or ...

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 ...

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 ...

Both the brain and the spinal cord are protected by bone: the brain by the bones of the skull, and the spinal cord by vertebrae, a set of ring-shaped bones. They're both cushioned by layers of ...

Flat feet are feet that do not have an arch. The middle of the foot touches the ground. Feet with no arches is the main sign of flat feet. Sometimes, flat feet can cause foot, ankle, or knee pain.

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

Walking pneumonia is a less serious form of the lung infection pneumonia. It's often caused by bacteria called Mycoplasma pneumoniae, but other bacteria or viruses can also cause it. Most kids with ...

I have lots of little bumps (almost like goosebumps or whiteheads) on my penis. Is this a sign that something is wrong? If you've never had sex, little white bumps on the shaft of the penis may be ...

A period is when blood comes out through a girl's vagina. It is a sign that she is getting close to the end of puberty. Puberty is when your body goes from looking like a kid's into looking more like ...

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 ...