Phospholipids comprise an important class of biological molecules that serve both structural and functional roles in the human body.

Vitamins and minerals are essential nutrients for a person's growth and development. Because they need to be absorbed from the bloodstream to be effective, anything that hinders this process can result in your body getting insufficient nutrients.

Your respiratory system is responsible for supplying your blood with oxygen. Your lungs allow you to absorb oxygen and breathe carbon dioxide out. Your trachea filters air you breath, while your diaphragm -- a rounded muscle -- supports healthy breathing.

When you begin a new exercise routine, you are eager to reap the health benefits. The time it can take for your body to adapt to the exercise depends on a few factors.

Little bumps on the ears might cause frustration and pain, especially if the bumps interfere with wearing glasses or earrings. If the bumps grow in size or number, ooze, change in color, cause pain or persist, seek medical evaluation as little bumps on the ear sometimes are a sign of a serious medical condition.

Before your body can use the food you eat for fuel, as well as for cell and tissue growth, the food has to go through the process of digestion. The digestive process begins in the mouth and continues in the stomach, where certain enzymes begin to break down foods into their basic components so cells can use them.

It’s rare to talk about therapy for your knees without discussing the low-impact benefits of cycling and elliptical workouts. Both are forms of exercise for knee injuries because keeping your knees mobile and strong can minimize further damage.

Ear barotrauma is the technical name for the feeling of pressure you may get that causes you to seek ways to unblock your ears. The root of the problem is simply an imbalance of pressure between your middle ear and the pressure outside your body.

Dehydration occurs when your body doesn't have as much fluid as it needs. You lose fluid through breathing, sweating, urinating, bowel movements and, when you're sick, through vomiting or diarrhea.

Calcium and phosphorus are essential minerals found in the bone, blood and soft tissue of the body and have a role in numerous body functions. Phosphorus levels can affect calcium levels in the body, and vice versa.

Female breasts come in all shapes and sizes, but dissatisfaction with breast size is a common complaint. While it's tempting for women to try gimmicks, vitamins or other supplements that claim to increase breast size, there is no scientific evidence that they work.

The human body is like a machine, with working parts that all contribute to the health and activity of the individual. Of course, this might be difficult to explain to kids -- particularly when it comes to the unseen parts, such as the muscular system.