Digestive System (Grade 10)
Students model the digestive system, learning about some of the digestive enzymes and physiology along the way.
What You Need
Activity 1: Travelling Through the Digestive System
Per class:
- 2 plastic cups (one for "bile" and one for "saliva"
- 1 disposable pipette
- green food colouring
- Photo showing the digestive system
- Paper towel roll or napkins
Per pair of students:
- 1 piece of table cloth cut the size of a desk
- 1/3 of a banana
- 2 graham crackers
- 1 ziplock bag
- 1 Dixie-type cup (3 oz.) with a hole in the bottom
- 1 Dixie-type cup (3 oz.) with no hole in the bottom
Activity 2: Creating a Paper Artwork of the Digestive System
- Glue
- Scissors
- Cardstock with digestive system parts
- White cardstock
PowerPoint:
Activity Guides:
See attached activity guide for alternative activity supply list and instructions for virtual learners.
Safety Notes
As a Let’s Talk Science volunteer, safety must be foremost in our minds during all activities. As STEM role models, volunteers must always also model safe science practices.
Always keep in mind the following precautions:
- Emphasize and demonstrate appropriate safety procedures throughout the presentation.
- Be professional but have fun.
- Keep workspaces clean to avoid tripping hazards.
- Allergens should have been checked before reserving the kit (e.g. allergies to latex).
What To Do
Pre-Activity Preparation
- Make bile by adding a few drops of green food colouring to one of the plastic cups, then add about 1/2 full of water (place the pipette near or in this cup)
- Fill the 2nd plastic cup with 3/4 cup of water (saliva)
- Fill each paper cup (the ones without the hole in the bottom) about 2/3 full of water
- Cut bananas into 3 or 4 – enough for each pair to have 1/4 - 1/3 of a banana
- Place a piece of tablecloth on each pair of students desk.
- Distribute to each pair of students – one paper cup with a hole in the bottom; one paper cup 1/2 filled with water; one pantyhose leg, 1 plastic baggie, 2 graham crackers; piece of banana.
Activity 1: Travelling Through the Digestive System
Complete this activity over a table cloth to help with clean-up. Discuss each part and function of the digestive system as they move through each step.
- Have the students ‘chew’ the graham cracker (1 per person), by placing it in their hand and squishing it. They should keep the cracker bits in their hand just as they would their real mouth.
- Pour a bit of water (saliva) into each of their hands as they are ‘chewing’. They should end up with a ball of food (bolus) when they are done ‘chewing’ just like we do in our mouths.
- Have them put the banana, both of their chewed-up graham crackers, and the water from the cup (stomach acid) into the bag (stomach). Have them seal the bag tightly without much air in the bag.
- Have them mush up the food and water in the stomach (until it’s fairly liquid and no big chunks). Remind them to be careful not to break the bag.
- Have them cut a hole in the bottom of the bag (valve called the pyloric sphincter), and pour it into only the top 1/3 of the panty hose leg. This will take 2 people. One cuts the hole in the bag and the other holds the panty hose leg open and places their other hand to keep the food going through the whole leg.
- When they have the food in the top 1/3 of the panty hose leg, add the bile (green food coloured water) using a pipette. You can let them know the teacher is squirting in bile.
- Also remind them again that most of the digestion takes place here.
- Have them squeeze the food through the pantyhose – it’s messy.
- Have the students cut valve (ileocecal sphincter), so the food can go into the large intestine (cup with the hole in it) and squeeze the food into the cup (large intestine).
- Have the students close the top of the cup and squeeze their waste through the hole (anus/anal sphincter) and poop out the undigested food onto the table cloth!
Activity 2: Creating a Paper Artwork of the Digestive System
Pass out 1 piece of white cardstock and one of each of the paper digestive system parts. Instruct students to cut these out and glue them to the paper in the proper place. They can label each organ and write something that the organ does (if time). You could have the PowerPoint slide up for this.
Discovery
Digestion begins in the mouth. Food is mechanically broken down via chewing and saliva is mixed to start digesting carbohydrates. After swallowing, food is moved down through the esophagus, through the esophageal sphincter and into the stomach. The main purpose of the stomach is to turn the food to liquid. The stomach adds acid to the food to help break it down. Afterwards, the food liquid moves through the pyloric sphincter to the small intestine. Majority of the digestion of fats, proteins and carbohydrates occur in the small intestine (broken into three parts- the duodenum, jejunum and ileum). In the duodenum, bile from the liver (and pancreatic enzymes) are added to aid in digestion. Food moves from the small intestine to the large intestine via the ileocecal valve. The purpose of the large intestine is to absorb water and eliminate undigested food (via the rectum and anus).
Our digestive system breaks down nutrients from food that we need to survive. Every system in our body uses the nutrients from our food in some way or another.
Different types of food serve different functions in our body- carbohydrates give us energy, proteins are broken into amino acids to build new proteins and fats provide energy, warmth and help with nutrient absorption.
What's Happening?
Digestion begins in the mouth. Food is mechanically broken down via chewing and saliva is mixed to start digesting carbohydrates. After swallowing, food is moved down through the esophagus, through the esophageal sphincter and into the stomach. The main purpose of the stomach is to turn the food to liquid. The stomach adds acid to the food to help break it down. Afterwards, the food liquid moves through the pyloric sphincter to the small intestine. Majority of the digestion of fats, proteins and carbohydrates occur in the small intestine (broken into three parts- the duodenum, jejunum and ileum). In the duodenum, bile from the liver (and pancreatic enzymes) are added to aid in digestion. Food moves from the small intestine to the large intestine via the ileocecal valve. The purpose of the large intestine is to absorb water and eliminate undigested food (via the rectum and anus).
Why is it Important?
Our digestive system breaks down nutrients from food that we need to survive. Every system in our body uses the nutrients from our food in some way or another.
Different types of food serve different functions in our body- carbohydrates give us energy, proteins are broken into amino acids to build new proteins and fats provide energy, warmth and help with nutrient absorption.
Resources
Activity Guides: