Body Basics

Articles In This Section

• Metabolism

  Your body gets the energy it needs from food through a process called metabolism. Get all the facts on metabolism in this article.

• Eyes

  Although your eyes are small, their structure is incredibly complex. Find out how they work in this body basics article.

• Male Reproductive System

  What makes up a guy's reproductive system and how does it develop? Can anything go wrong? Find the answers to these questions and more in this article.

• Female Reproductive System

  Why do girls get periods? What goes on when a woman gets pregnant? What can go wrong with the female reproductive system? Find the answers to these questions and more in this article for teens.

• Lungs and Respiratory System

  Each day you breathe about 20,000 times. Find out more about the lungs and breathing process.

• Heart and Circulatory System

  The heart and circulatory system (also called the cardiovascular system) make up the network that delivers blood to the body's tissues.

• Spleen and Lymphatic System

  The lymphatic system is an extensive drainage network that helps keep bodily fluid levels in balance and defends the body against infections.

• Skin, Hair, and Nails

  Our skin protects the network of tissues, muscles, bones, nerves, blood vessels, and everything else inside our bodies. Hair and nails are actually modified types of skin.

• Kidneys and Urinary Tract

  The kidneys perform several functions that are essential to health, the most important of which are to filter blood and produce urine.

• Mouth and Teeth

  Did you know that your mouth is the first step in the body's digestive process? Or that the mouth and teeth are essential for speech? Learn about the many roles your mouth and teeth play.

• Immune System

  The immune system is made up of special cells, proteins, tissues, and organs that defend people against germs and microorganisms. It's the body's defense against organisms and substances that invade our systems and cause disease.

• Digestive System

  Most people think digestion begins when you first put food in your mouth. But the digestive process actually starts even before the food hits your taste buds.

• Blood

  Without blood, our organs couldn't get the oxygen and nutrients they need, we couldn't keep warm or cool off, we couldn't fight infections, and we couldn't get rid of our own waste products. Find out about the mysterious, life-sustaining fluid called blood.

• Endocrine System

  The endocrine system influences almost every cell, organ, and function of our bodies. It is instrumental in regulating mood, growth and development, metabolism, and sexual function, among other things.

• Bones, Muscles, and Joints

  Our bones, muscles, and joints form our musculoskeletal system and enable us to do everyday physical activities.

• The Basics on Genes and Genetic Disorders

  Genes play an important role in how we look and act, and even in whether we get sick. This article gives the lowdown on genes, genetic disorders, and new research into gene therapy.