Elementary School Science

Input:
What is the most important content in this lesson?
To reach this lesson’s objective, students need to understand:

• The organs of the digestive system.

• The function of each organ of the digestive system.

• The process of digestion.

• Pathologies/ illnesses that can occur in the digestive system.

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How will the learning of this content be facilitated?

• The class will begin with the teacher showing the video “Digestive System- Human Body for Kids- How the Body Works” (source: https://www.youtube.com/watch?v=COQJwDcSajw). The video is about 7 minutes long and describes the process of digestion. After the video is shown, the teacher should show the students the two pieces of string and ask the students if they remember which intestine is 25 feet and which intestine is 5 feet. The teacher should next begin a discussion about the video and the students’ reactions to the video.

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• Next, the teacher should hand out the “Diagram of the Digestive System”. If it is possible, project the “Diagram of the Digestive System” onto the board using a projector or put into a PowerPoint document and project so that the teacher can point to the while they explain. As the teacher explains, the students will write the name of each organ on the line. From this activity, the students will learn about the organs of the digestive system and the function of each part.

• Organs of the Digestive System

  • Salivary Glands: glands that produce saliva or spit. The saliva moistens your food so that you can swallow it easily.

  • **It is good to mention that a bolus is what we call chewed food**

  • Tongue: our tongue helps to food down our throat.

  • Epiglottis: a flap of cartilage located at the root of the tongue; during swallowing, it covers the windpipe to prevent food from going into the lungs. If you eat or drink something too fast, the epiglottis may not have enough time to cover the windpipe; this results in coughing/choking.

  • Esophagus: about 10 inches; pipe that moves the food from the throat into the stomach. It takes about 2 to 3 seconds for the food to get from the esophagus into the stomach.

  • Liver: located on the right side of the belly. Produces a special liquid called bile that allows the body to absorb fat into the bloodstream.

  • Stomach: a pouch where the food passes through from the esophagus to the small intestine. Gastric juices located in the walls of the stomach help to break down food and kill any bacteria that may be in the food that can get us sick.

  • Gallbladder: located on the right side of the belly. Bile is stored here until the body needs it to digest fats.

  • Pancreas: a gland located behind the stomach. Secretes special hormones into the bloodstream and special digestive enzymes into the small intestine. The pancreas helps digest fats and protein.

  • Duodenum: first part of the small intestine.

  • Illeum (Small Intestine): the last portion of the small intestine. Digestion occurs in the small intestine.

  • Colon: the last place the food waste enters before being exited as stool. As waste travels through the colon, more and more water is absorbed, which is why stool is hard.

  • Caecum: pouch at the beginning of the large intestine.

  • Appendix: tiny tube located in the large intestine; serves no purpose. However, when the appendix becomes infected, it must be removed.

  • Rectum: where the stool stays until it is ready to be exited as a bowel movement..

  • Anus: the hole that you push the stool out of.

  • **It is important to note that the colon, caecum, rectum, and anus make up the large intestine. Leftover waste from digestion (waste the body does not need) goes into the large intestine. A bowel movement occurs, which is how the waste is removed**

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• Information Source: http://kidshealth.org/en/kids/digestive-system.html?ref=search#

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• Once the worksheet is explained, the teacher should tell the students they will be learning about some pathologies (illnesses) of the digestive system. The teacher should explain again that gastric acid helps to break down food as well as kill some of the bacteria that may be in the food and can cause illnesses. However, sometimes the bacteria aren’t killed and illnesses occur. The teacher should hand out the “Pathologies of the Digestive System” worksheet. If it is possible, project the “Pathologies of the Digestive System” onto the board using a projector or put into a PowerPoint document and project so that the teacher can point to the while they explain. As the teacher explains, the students will write the name of each illness in the box. From this activity, the students will learn about some of the illnesses that can occur, symptoms, and what causes them.

• The students will break into pairs. The teacher should tell the students they will be ordering the process of digestion. Each student will be given a “Process of Digestion” worksheet and “Digestion Cards”. The students will cut out the cards and glue them into the correct box to show the correct process of digestion. Allow the students about 15 minutes to work on their project. Reconvene when 15 minutes is over and review the worksheet/ activity.

Answers

1. Mouth/Teeth

2. Tongue

3. Esophagus

4. Stomach

5. Liver/Gallbladder

6. Pancreas

7. Small Intestine

8. Large Intestine

9. Rectum

• The final assessment will be for the students to answer the question:

Think about what you learned in class today. Why is the digestive system important? Is the stomach the only organ involved in digestion? What helps us break down food we eat? Does all of the food go from the small intestine to the large intestine?