(MOS) Digestion Lesson
Digestion Lesson
Like the Circulatory System, the Digestive System has an important role to play in keeping the body healthy. What components make up the digestive system? What is its function? How is this system structured to do its job efficiently? For answers to the questions above, watch the presentation about the Digestive System.
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Food provides us with energy. Whether you are a vegetarian or an omnivore, your body needs food to carry out metabolic processes and maintain homeostasis. Our bodies break down food into smaller substances that can be used by our cells.
These tiny substances are called nutrients. The six major nutrients essential for maintaining a healthy body are carbohydrates, fats, proteins, vitamins, minerals, and water. We get our carbohydrates from sugary foods and items that contain starch such as bread and pasta. Dairy products, eggs, fish, and meats are fatty foods. Meats as well as eggs, grains, and beans provide a great source of protein in your diet. Vitamins and minerals are only needed in small amounts. You can obtain vitamin C from citrus fruits and dark green vegetables. Dairy products contain vitamins A, D, and B12. Vitamin K helps your blood to clot when you get a scrape or cut. Folic acid, a vitamin found in green leafy vegetables, is needed for red blood cell formation. You obtain minerals by eating plants. Calcium, iron, and potassium are just a few minerals you need in your body to carry out chemical processes. Calcium is needed for strong bones and teeth. Eating a banana is a good source of potassium which also helps maintain muscle and nerve function. Water is the most vital nutrient. It is the most abundant substance in your body. Water is found in blood, sweat, and tears. Substances and other nutrients are dissolved and transported in the watery portion of blood. Digestion is the process by which the body breaks down food particles into nutrients that can be used by the organism.
There are three major stages of the digestive system.
- The breakdown of food particles
- The absorption of food molecules into the blood
- The elimination of unwanted waste particles
Digestion begins inside the mouth. Teeth break down food particle into smaller pieces. The salvia inside your mouth has chemicals that not only moisten food but also aid in the breakdown of food particles. When you swallow, the food particles travel from your mouth down the esophagus to the stomach. The smooth muscles that line the stomach contract to churn and break down the food particles. Pepsin and hydrochloric acid are digestive enzymes within the stomach that help to continue the digestion process by breaking down proteins in the food particles until it is transformed into a thick liquid. This liquid form of food leaves the stomach and ends up in the small intestines. This is where absorption of nutrients takes place in your body. The liver releases bile into the small intestine to break down fats. The pancreas also produces an enzyme to flow into the small intestine to break down not only the remaining fat droplets but also starches and proteins. Water is absorbed into the bloodstream as it is removed from the undigested food when it enters the large intestine. The undigested food or waste is now ready to exit your body through a short tube at the end of the large intestine called the rectum. Finally, the waste material is removed from your body through a muscular opening at the end of the rectum called the anus.
Major Organs Self-Assessment
Complete the following activity to test your knowledge of what you've learned in this module thus far.
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