Aim
To study the structure and functioning of the human digestive system, including the processes of digestion and nutrient absorption.
Materials Required
- 3D model or diagram of the human digestive system
- Food samples (carbohydrates, proteins, fats)
- Test tubes and droppers
- Reagents for testing nutrients (e.g., iodine, Benedict’s solution, Biuret reagent)
Image Reference
Procedure
- Observe the model or diagram of the human digestive system and identify the organs involved, such as the mouth, esophagus, stomach, small intestine, large intestine, liver, pancreas, and gallbladder.
- Understand the role of each organ:
- Mouth: Ingestion and mechanical digestion (chewing).
- Stomach: Secretes gastric juice for protein digestion.
- Small Intestine: Absorbs nutrients through villi.
- Liver and Gallbladder: Produce and store bile for fat emulsification.
- Pancreas: Secretes enzymes for digestion of carbohydrates, proteins, and fats.
- Large Intestine: Absorbs water and forms feces.
- Perform a simple nutrient test:
- Test for starch: Add iodine solution to a food sample. A blue-black color indicates the presence of starch.
- Test for glucose: Add Benedict’s solution and heat the mixture. An orange-red precipitate indicates the presence of glucose.
- Test for proteins: Add Biuret reagent to a food sample. A violet color indicates the presence of proteins.
Observation
The human digestive system is a complex process involving:
- Mechanical digestion in the mouth and stomach.
- Chemical digestion of carbohydrates, proteins, and fats using enzymes and bile.
- Absorption of nutrients in the small intestine through specialized structures called villi.
- Water reabsorption and waste elimination in the large intestine.
Inference
The digestive system breaks down food into simpler forms that the body can absorb and use for energy, growth, and repair. Each organ plays a specific role in ensuring efficient digestion and absorption.
Precautions
- Handle reagents carefully and follow safety guidelines while performing tests.
- Label test tubes properly to avoid confusion during nutrient tests.
- Ensure accurate observation of the digestive system model or diagram.