Our bodies run on fuel and give off wastes much like a car uses gasoline to run and gives off exhaust fumes. Instead of gasoline, our bodies need good food for fuel. There is a long tube running the whole length inside our body, called the alimentary canal , that carries the food from the mouth, processes the nutrients from the food, and disposes of the solid wastes that are left over.

Let’s follow that hamburger from dinner through your body.

Digestive System

            The teeth break the food into small pieces in the mouth. Enzymes in the saliva from the six salivary glands start to break down starches, such as those found in the bread, into sugars. When you swallow, the epiglottis protects your windpipe, or trachea , so the food won’t "go down the wrong way". Peristalsis pushes the food through the digestive tract, or alimentary canal. The esophagus is the part of the alimentary canal that connects the mouth to the stomach. The stomach is a muscular sack that churns the food and makes digestive juices that contain acid . This acid changes the food into a pulpy material called chyme . When the food is squeezed into the small intestine, several digestive juices are added. Bile , stored in the gall bladder , is added from the liver . The pancreas adds pancreatic juice, and the walls of the intestines also make digestive juices. After the food is completely broken into its nutrients, the villi in the intestinal wall pass the nutrients into the bloodstream. These nutrients are the chemical building blocks our bodies use to make cells and give the cells the energy they need to do their work.

            The small intestines are about 22 ft. long. By the time peristalsis has pushed the material to the end of the small intestine, very little digestible material is left. The waste material is then pushed into the large intestine. There is a small sack, called the appendix , where the small and large intestine meet. Sometimes this sack gets infected. We say we are having an appendicitis attack, and we may need an appendectomy , or surgery to remove the sack.

Excretory System

            As the waste material travels through the large intestine, or colon , water is pulled out of this waste and put back into the blood stream. The waste becomes harder. It is stored in the last section of the large intestine, called the rectum , where it is held until the sphincter muscles relax at the opening at the end of the alimentary canal. This opening is called the anus .

            The colon, or large intestines, sweat glands, liver, and the kidneys make up the excretory system. It is the job of the kidneys to filter out of the blood any chemicals that can harm us. Many of these harmful chemicals are the natural result of the chemical reactions that turned the hamburger into nutrients for your cells. These chemicals act like poisons to the body and must be "washed out." As the blood travels through the kidneys these poisons are collected and sent to the bladder as urine . The liver also acts as a natural filter for harmful chemicals in the body. When a person chooses to put bad chemicals into their bodies, such as alcohol or tobacco, it is the job of the liver and kidneys to clean up the mess. That is why it is so easy to damage the liver and kidneys if a person abuses drugs. Once damaged, the kidneys cannot repair themselves. A person can live with just one kidney, but must be put on a dialysis machine to stay alive if both kidneys fail. The liver does have the ability to heal itself to some extent, or regenerate . When the kidneys or liver don’t work any more the only way that person can lead a normal life is to have a transplan t operation. These are very serious surgeries that are not always a success.

Here's to Good Health