The Digestive and Excretory Systems

The Digestive System

The digestive system breaks down all of the substances we eat and drink into their simplest forms: lipids, carbohydrates, water, vitamins, minerals, and protein. There are two types of digestion: mechanical and chemical. Mechanical digestion is breaking food down by grinding it. Chemical digestion is breaking food down with the use of fluids, chemicals, and enzymes. Anything that is not digested or broken down is removed from the body through another system called the excretory system. The molecules that are broken down are used by cells through the efforts of the circulatory system. Like the other systems, the digestive system works collaboratively with other systems to maintain homeostasis in the body.

Main Organs

The the main organs of the digestive system include the mouth, pharynx, esophagus, stomach, small intestine, and large intestine. In this interactivity, learn more about these organs and their role in the digestive process. Click on the player button to begin.

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Accessory Organs

When you think of the parts of the digestive system, you may immediately consider the stomach and the intestines. In addition to these very important components, there are also accessory organs that aid in the digestive process. These accessory organs include the tongue, teeth, salivary glands, pancreas, liver, and gall bladder.

To tongue assists the digestive process by helping you chew and taste your food. Your teeth break down the food you eat by ripping, tearing, and crushing it. In the back of the mouth are the salivary glands, which secrete saliva. The saliva contains mostly water, but it also contains enzymes to help break down food.

The main function of the pancreas is to produce insulin and pancreatic fluid, which help to break down food in the small intestine. The liver does not process food, but it produces bile, which is stored in the gall bladder. Bile is needed in the small intestine to break down fats in the food you eat, so that they are in usable form for absorption. The liver also stores vitamins, minerals, and produces cholesterol.

 

The Excretory System

The excretory system is responsible for ridding the body of toxins and waste products. Many of these products are excreted during normal functions, for example: the lungs expel carbon dioxide and the sweat excreted from the skin expels salts and other substances. Most toxins and wastes, however, are processed through the kidneys.

The kidneys help the body maintain homeostasis, the internal balance that keeps you alive and allows your cells to function. The kidneys keep your blood healthy by removing wastes, regulating water content and volume, and monitoring pH. Your kidneys filter all of the blood in your body approximately every forty-five minutes. After blood passes through the kidneys, it is purified and can continue to circulate in the body. The wastes that have been filtered from the blood, usually water and natural products of metabolism called urea, are passed from each kidney into a tube called the ureter. The ureter carries these wastes, now known as urine, to the bladder. Urine is stored in the bladder until it is released from the urethra.

The excretory system includes the kidneys, which purify blood and rid the body of wastes.

Because the kidneys play such a major role in purifying your body, kidney disorders are a major health concern. If an individual’s kidneys become unable to function, dialysis may necessary. Dialysis helps the body maintain homeostasis by using a machine to cleanse the blood of wastes and returns the purified blood to the body. Because a healthy individual can live with only one kidney, organ donation is an option to help individuals suffering from kidney disorders. Doctors are also working to develop artificial organs, including kidneys, to help those that are waiting on kidney transplants.

 

The Digestive and Excretory Systems Review

Now that you have learned about the digestive and excretory systems, check your understanding. In this non-graded interactivity, reach each statement and select the correct response. Click the player button to get started.