The temporomandibular joint (TMJ) connects the lower jaw to the skull. You can feel your two TM joints and their movement by placing your fingers directly in front of your ears and opening your mouth.

Staying safe means you can have more fun! Learn how to play it safe at home, outdoors, and on the road.

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 ...

The nervous system controls everything you do, including breathing, walking, thinking, and feeling. This system is made up of your brain, spinal cord, and all the nerves of your body. The brain is the ...

Newborns and infants can't lift their heads well. So they can get stuck in a position that blocks their breathing, called smothering or suffocation. Young children have better head control, but still ...

What Is a Perforated Eardrum? A perforated eardrum is a tear or hole in the ear's tympanic membrane (the eardrum). A perforated (PER-fer-ate-id) eardrum can hurt, but most heal in a few days to weeks.

Doctors use certain milestones to tell if a preschooler is developing as expected. There's a wide range of what's considered normal, so some children gain skills earlier or later than others. Kids who ...

A wet dream — also called a nocturnal emission — is when a male ejaculates or "cums" while sleeping. During ejaculation, semen (the fluid that carries sperm) comes out of the penis. When you wake up ...

There's no cure for HIV/AIDS, but medicines can help people live long, healthy lives. HIV attacks cells in the immune system called CD4 cells (or T cells). CD4 cells help the body fight off infections ...

How Does the Brain Work? And How Does the Nervous System Work? How do you remember the way to your friend's house? Why do your eyes blink without you ever thinking about it? Where do dreams come from?

What's the Urinary System (Urinary Tract)? The urinary system (also called the urinary tract) is one of the systems our bodies use to get rid of waste products. The kidneys are the part of the urinary ...

A person also can get infected if they touch poop with the bacteria in it and then get it in their mouth. This can happen from swimming in or drinking contaminated water or by touching an infected pet ...