Digestive System

Detailed Lesson Plan in Science for Grade VIII Prepared By: Raslia P. Ronda I.

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Learning Outcomes: At the end of the lesson, the Grade VIII students will be able to: a. Differentiate the processes involved in Digestive System. b. Trace the flow of food as it is being digested. c. Appreciate the importance of Digestion. Learning Content: A. Topic: Digestive System B. References: 1. Textbooks: Mariano, Jan Jason. (2012) Science Links II (Biology). Sampaloc, Manila: Rex Book Store, Inc. Learner’s Module: Campo, Pia, et.al (2013) Science Grade 8 Learner’s Module. Pasis City: Vibal Publishing House, Inc. C. Instructional Materials: Visual aids (Picture of Human Digestive System), Scrambled words, Strip words, and Choey choco. D. Science Ideas: a. Human digestive system is a series of organs that converts food into essential nutrients that are absorbed into the body and moves the unused materials out of the body. b. There are five processes involved in Digestive System. These are the Ingestion, Digestion, Absorption, Assimilation, and Excretion. Ingestion is the process of taking food into mouth. Digestion is the process of breaking down food by mechanical and enzymatic action in the alimentary canal into substances that can be used by the body. Absorption is the process of absorbing nutrients into your bloodstream. Assimilation is the process of nutrients becoming part of the tissues of the body. Excretion is the process of discarding wastes from your body. Learning Strategies

Teacher’s Activity A. Preparatory Activity:

Student’s Activity

1. Prayer “Everybody, please stand for the prayer.” “Take your seats.” 2. Greetings

(The students will stand and pray) (The students will sit down)

“Good afternoon class!” “How are you doing?”

“Good Afternoon Ma’am Ras!” “We’re doing fine Ma’am.”

3. Checking of Attendance “I’m glad to hear that. Who are absent today?”

“Nobody is absent today!”

“Very good!” 4. Recapitulation “What was our topic yesterday?”

“Our topic yesterday was

B. Motivation (The teacher will give each student a choey choco and the students will eat it slowly.) “What do you think happen to chocolate when you ate it?”

“The chocolate broken down into small pieces.”

“That’s right! When you ate the chocolate, it breaks down into pieces and will be digested into the stomach.” “So, what do you think is our topic today?” “That’s right! Let’s have an activity.” Pre-Lab Activity: (The teacher will post drawing of human digestive system on the board. The students will work with two groups. The teacher will give each group a small envelope with the name of different parts of the digestive system. The teacher will blow a whistle for the teams to open their envelope and race to arrange the scramble word: Mouth, Esophagus, Stomach, Small Intestine,

“Our topic today will be digestive system.”

Large Intestine, Liver, Gallbladder, Pancreas, Rectum, and Anus. After they’ve arranged it, the students will label the human digestive system using the words they’ve arranged. ) Laboratory Proper: Post-Lab Activity:

(The students will perform the activity.)

“Mouth Ma’am.”

1. Process: “What is the first organ involved in Digestive System?” “That’s right! What process is involved when you put the food in your mouth?”

“Ingestion Ma’am.” “Ingestion is the process of the food entering the mouth.” “The digestion begins in the Mouth.”

“What is ingestion?” “Very good! Where do you think digestion begins?” “Yes. Digestion begins in the mouth specifically in the oral cavity. What is digestion?” “Yes. Digestion is simply the breakdown of food into smaller components. There are two forms of digestion. What are the two forms of digestion?”

“Digestion is the process of breaking down of food into smaller component.”

“The two forms of Digestion are Mechanical digestion and Chemical digestion.” “Mechanical Digestion is the process of breaking down of food.”

“That’s right! What is Mechanical Digestion?” “Yes. Mechanical digestion is simply the breaking down of food into progressively smaller and smaller particles through tearing, cutting, grinding, and the moving of food along the digestive tract. What is Chemical Digestion?” “Very good! Chemical digestion is the

“Chemical digestion is the process of converting food into substances.”

process where food is converted to substances usable by the body. Substances called enzymes speed up this process. Your oral cavity receives the food and begins the preparation of food for digestion. Food is torn and ground into smaller pieces through chewing. Tongue moves the food around your oral cavity so that all food can be ground up. Food is now a wet and become a bolus. Where do you think bolus will go after the mouth? ”

“The bolus will go to esophagus.”

“That’s right! The bolus will push into the pharynx with the aid of your tongue. Tongue cannot push food all the way down to the stomach. And the bolus is moved further downward by rhythmic, muscular contractions of the Pharynx, known as Peristalsis.”

“Esophagus is a long flexible-tube like structure.”

“What is esophagus?”

“The next stop is the stomach Ma’am.”

“Very good! Esophagus is where the bolus passes through to go to the stomach. Its important function is to carry food, liquids, and saliva from the mouth to the stomach. Where’s the next stop of bolus?” “Yes. The bolus continues its journey to this J shaped expanded bag called the Stomach. What is the function of Stomach?” “That’s right! The stomach is the main food storage tank of the body. It also secretes a mixture of acid, mucus, and digestive enzymes that helps to digest and sanitize our food while it is being stored. This organ is filled with gastric juices and mucus. What is gastric juice?” “Yes. Pepsin is an enzyme that breaks down the proteins found in food. The

“The function of the stomach is to digest further the bolus.”

“Gastric juice is an acidic substance composed mainly of pepsin.”

“The next stop is the small intestine.”

stomach makes a churning action by way of muscle contractions. This action increases the effectiveness of gastric juices. In the stomach bolus become semiliquid, creamy, homogeneous substance called “chyme. Where does chyme’s next stop?” “Very good! Chyme leaves the bottom of the stomach through the pyloric sphincter and travels a short way to the small intestine. There are two processes involved in the small intestine. What are these?” “Very good! What is Absorption?”

“The two processes involved in the small intestine are Absorption and Assimilation.” “Absorption is the uptake of fluids or other substances by the tissues of the body.”

“Assimilation is the process of uptake of nutrients into cells and tissues “The main function of small intestine is to absorb the nutrients and minerals.”

“Yes. Absorption is the process of the food molecules being absorbed into the blood stream. What is Assimilation?” “That’s right! Assimilation is the process by which chemicals from food are taken into the cells. What is the main function of small intestine?” “Very good! The small intestine breaks down the food mixture even more so your body can absorb all the vitamins, minerals, proteins, carbohydrates, and fats. In the small intestine digestion continues. Where’s next stop of chyme after small intestine?” “Yes. What will happen to the chyme in large intestine?” “That’s right! Nutrients not absorbed in small intestines are absorbed in the large intestine as is some of the water. It also serves as the storage and elimination structure for indigestible substances. Still

“The next stop is the large intestine.” “The large intestine will reabsorb the water from the chyme.”

“Feces is the left over solid bits of waste.” “The feces will go to rectum.”

“The main function of rectum is to act as a temporary storage site for fecal matter

in the form of chyme when it enters, but in the colon, chyme is converted into feces. What is feces?”

before it is eliminated.” “In the anus or anus canal.”

“Very good! Where does feces go after?” “Yes. When the descending colon becomes full of feces, it empties its contents into the rectum to begin the process of elimination. What is the main function of rectum?”

“Excretion is the process of discarding the waste from your body.” “Yes Ma’am.”

“That’s right! Where does feces pass through to be eliminated?” “Yes. Feces will be eliminated through your anus canal. And this is the process of excretion. What is excretion?” “Very good! Excretion is the final process of Digestive system. Did you understand?” 2. Activity (See attached activity sheet.) 3. Generalization “What have you learned from our topic today?”

“Very good! What is the importance of Digestion?” IV.

Evaluation

Identification. Direction: Write your answers on the space provided. ______ 1. The process of taking food into your mouth.

“I have learned that there are five processes involved in digestive system. These are the Ingestion, Digestion, Absorption, Assimilation, and Excretion.” “Digestion is important because

______ 2. The process of absorbing nutrients into your bloodstream. ______ 3. The process of eliminating the wastes through anus/anus canal. ______ 4. The process of nutrients becoming part of the tissues of the body. ______ 5. The process of breaking down food into smaller components. V.

Assignment Short bond paper. Make a diagram of the flow of food through the Digestive System.

Digestive System Project You are about to be assigned a starring role in the play, “The Stomach Churns.” Once the director assigns you a role, you are to write a short monologue in which you explain your role in the digestive system. You also are to create a costume with props which relates to your role and will create a visual image. Practice your role and be “dramatic!” The director will give you your cues as to when you are to appear on stage. Remember you are that organ.

“LIGHTS........CAMERAS.............ACTION” “THE STOMACH CHURNS” STARRING: “Meredith Mouth”............................. “Edwina Esophagus”......................... “Samantha Stomach”......................... “Sally Small Intestine”...................... “Lucy Large Intestine”......................

“Ricky Rectum”................................ “Director Doug”................................