The Human Digestive System
Understanding the Organs and Functions of the Digestive System
Learning Standards
Content Standard
The learner demonstrates understanding of the major organs and their functions in the human body system
Performance Standard
The learner should be able to describe how the digestive system works
Learning Competency
Describe the functions of the different organs of the digestive system
Code: S5LT-IIa-1
Complete Lesson Plan
Learning Objectives
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Identify the organs of the digestive system
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Describe the function of each digestive organ
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Explain the process of digestion
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Trace the path of food through the digestive system
Lesson Procedures
motivation
Ask students to think about breakfast. 'You ate rice this morning. Where is it now? What happened to it? Let's follow the journey of food through your body!'
presentation
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Explain: 'Your body is like a food processing factory! Food goes through many stations to be broken down into tiny nutrients.'
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1. MOUTH (Oral Cavity)
- Process: Mechanical digestion begins
- Functions:
- Teeth chew and grind food into smaller pieces
- Saliva moistens food and starts breaking down carbohydrates
- Tongue pushes food to the back for swallowing
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2. ESOPHAGUS
- Process: Transportation
- Function: Muscular tube that pushes food to the stomach through wave-like movements (peristalsis)
- Takes about 6-8 seconds
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3. STOMACH
- Process: Further mechanical and chemical digestion
- Functions:
- Churns and mixes food with gastric juices
- Produces acid to kill bacteria
- Breaks down proteins
- Food becomes liquid-like mixture called chyme
- Food stays for 2-4 hours
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4. SMALL INTESTINE
- Process: Main site of digestion and nutrient absorption
- Functions:
- Longest part (about 6 meters)
- Completes breakdown of carbohydrates, proteins, and fats
- Absorbs nutrients into the bloodstream
- Helped by: liver (bile), pancreas (enzymes), gallbladder
- Food stays for 3-5 hours
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5. LARGE INTESTINE (Colon)
- Process: Water absorption and waste formation
- Functions:
- Absorbs remaining water and minerals
- Forms solid waste (feces)
- Stores waste until elimination
- Waste stays for 12-24 hours
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Supporting Organs:
- Liver: Produces bile to digest fats
- Pancreas: Produces enzymes to break down all food types
- Gallbladder: Stores and releases bile
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Show complete diagram with arrows showing path
generalization
Questions:
- What is the digestive system?
- What are the main organs involved?
- Where does digestion begin?
- Where are most nutrients absorbed?
- Why is digestion important?
guided practice
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Trace the path of food together:
- Mouth → chewing and saliva
- Esophagus → pushes food down
- Stomach → churns and adds acid
- Small intestine → absorbs nutrients
- Large intestine → absorbs water, forms waste
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Fill in the blanks as a class:
- Digestion starts in the __________.
- The __________ is a long tube connecting mouth to stomach.
- Most nutrients are absorbed in the __________.
- The __________ produces bile to digest fats.
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Role play: Students act as food traveling through the system
independent practice
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Activity 1: Label the digestive system diagram:
- Mouth
- Esophagus
- Stomach
- Small intestine
- Large intestine
- Liver
- Pancreas
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Activity 2: Match organ to function:
| Organ | Function | |-------|----------| | Mouth | Absorbs nutrients | | Stomach | Chews food | | Small intestine | Churns food | | Large intestine | Absorbs water |
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Activity 3: Number the steps in order (1-5):
- ___ Food is churned in the stomach
- ___ Nutrients are absorbed
- ___ Food is chewed
- ___ Water is absorbed, waste formed
- ___ Food travels down the esophagus
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Activity 4: Draw the digestive system and trace the path of food with arrows
preliminary activities
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Prayer and greetings
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Review: Basic needs of the body (food, water, air)
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Question: What happens to the food we eat?
Assessment
answers
- Mouth, esophagus, stomach, small intestine, large intestine
- Churns food, adds acid, breaks down proteins, turns food into chyme
- Small intestine
- Produces bile to digest fats
- False, True, False, True
evaluation
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Answer:
- List the 5 main organs of the digestive system in order
- What happens in the stomach?
- Which organ absorbs most nutrients?
- What is the function of the liver?
- True or False:
- Digestion begins in the stomach (____)
- The small intestine is longer than the large intestine (____)
- The esophagus produces digestive enzymes (____)
- The large intestine absorbs water (____)
Materials & Resources
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Digestive system diagram/anatomical model
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Pictures of each organ
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Chart paper
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Colored markers
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Plastic tubing (to show path)
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Manila paper
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Worksheets with diagrams
assignment
Homework:
- Draw and label the digestive system with all major organs
- Write a short story: 'A Day in the Life of a Rice Grain' - describe its journey through the digestive system
- Research: How long does it take to digest different foods?
Remarks:
- Use digestive system models if available
- Emphasize the importance of healthy eating and proper chewing
subject matter
Topic: The Human Digestive System
Key Concepts:
- Digestive system breaks down food into nutrients the body can use
- Major organs: mouth, esophagus, stomach, small intestine, large intestine
- Supporting organs: liver, pancreas, gallbladder
- Digestion is both mechanical (chewing) and chemical (enzymes)
- Process takes about 24-72 hours from eating to waste elimination
Materials:
- Digestive system diagram/model
- Pictures of digestive organs
- Chart paper
- Markers
- Plastic tubing (to demonstrate path)
- Manila paper