The digestive system is made up of organs that break down food into protein, vitamins, minerals, carbohydrates, and fats, which the body needs for energy, growth, and repair. After food is chewed and swallowed, it goes down the esophagus and enters the stomach, where it is further broken down by powerful stomach acids. From the stomach, the food travels into the small intestine. This is where your food is broken down into nutrients that can enter the bloodstream through tiny hair-like projections called microvilli. Food that the body doesn't need or cannot digest passes to the large intestine (colon), which absorbs water. The solid waste is then eliminated from the body.

The major organs of the excretory system are the large intestine (colon), kidneys, and bladder.

The kidneys filter the blood, reabsorbing most of the water and removing waste substances. This, in turn, maintains the body’s fluid and mineral balance. The bladder is where the urine from the kidneys is stored. When the bladder is full, the urine passes through a small tube called the urethra (you REETH ruh) and is eliminated from the body.

Food that the body doesn't need or cannot digest passes to the colon (large intestine), which absorbs water. The solid waste is then eliminated from the body.

In addition to these structures, the skin plays a major role in excretion. It helps the body get rid of excess water, salts, and other wastes in perspiration, or sweat.