You have just eaten a meal of pancakes and maple syrup. All systems are working well. What happens?

1. Pour about 15 glucose pieces on the balance and tilt the balance. Respond as directed.

2. Release 5 insulin into the blood stream.

3. Insulin is carried to the cells. Place insulin onto each receptor on the liver, fat and muscle. The insulin/receptor combination activates a channel for the glucose to move into the cell in muscle and fat cells. In the liver, the channel is always active.

4. Move glucose into the liver, fat and muscle. The muscles can take up a lot of glucose, so move more glucose into the muscles.

5. Don’t forget to feed the brain! Without insulin receptors, glucose can move freely into the brain. Give the brain one glucose.

6. Continue moving glucose into organs until blood glucose is back to the normal level (3 glucose remain on the balance).

7. Arrange the glucose in the muscle and liver into chains to represent stored glucose in the form of glycogen.

8. Once glucose in the blood is decreased, insulin can be removed from the receptors.

This is the end of Scenario One. Keep your board as it is to begin Scenario Two.

You’ve been sitting in school and haven’t eaten in hours! All systems are working well, and you are hungry. What happens?

1. Start with three glucose on the balance.

2. Your brain is hungry! Feed it one glucose from the balance and move the balance accordingly.

3. Release 5 glucagon into the blood stream.

4. Place a glucagon on its receptor on the liver. The glucagon/receptor combination results in glucose being released from the liver by breaking down glycogen.

5. Move 2 glucose out of the liver into the blood stream.

6. Your brain needs energy again. Give it another glucose.

Clear your model board. Please answer the questions about Scenarios One and Two on your Student Sheet.

A person has become overweight and eats a meal of pancakes and maple syrup. The systems that maintain blood glucose levels are starting to fail. What happens?

Insulin Resistance: When our bodies are overweight, especially around the middle, our insulin receptors become changed and do not bind insulin as well.

1. 1. 1. Place a small sticky note on each insulin receptor to show that it is insulin resistant.

      2. Pour about 15 round pasta pieces into the pan on the balance, tip the balance, and respond as directed.

      3. Release 5 insulin into the blood stream.

      4. The resistant insulin receptors cannot bind insulin at this concentration. Show that muscle, liver and fat do not take up glucose.

      5. The blood glucose levels are still high, and the balance is still tipped. The pancreas releases more insulin. Release 5 more insulin into the blood stream.

      6. At this higher insulin level, some insulin receptors bind insulin. Remove the sticky notes from two receptors and put insulin on those receptors.

      7. Liver, fat and muscle can take up some of the glucose in the blood. Move 5 glucose molecules into the tissues with insulin on the receptors.

      8. Blood glucose is still high, so the pancreas releases more insulin. Release 5 more insulin in the blood stream.

      9. More receptors bind insulin. Remove the sticky notes from the remaining receptors and put insulin on all its receptors.

      10. Liver, muscle and fat take up more glucose from the bloodstream. Move glucose out of the blood and into the liver, muscle and fat.

Clear the model board. Please answer the questions about Scenario Three on your Student Sheet.

A person has been insulin resistant for years and has consistent high levels of blood glucose. The systems that maintain blood glucose levels are continuing to fail. What happens?

Beta Cell Damage: High levels of blood glucose trigger the β (beta) cells in the pancreas to release lots of insulin, as you saw in the previous scenario. When a person becomes insulin resistant, the β cells must work hard to release enough insulin. Over time, the β cells become damaged and cannot make enough insulin. Once the damage has been done, diabetes becomes a life-long condition that will always require management.

1. 1. 1. Place a small sticky note on the pancreas to represent β cell damage.

      2. Pour about 15 glucose pieces on the balance, tip the balance, and respond as directed.

      3. Release one insulin into the blood stream. Show that muscle, liver and fat cannot take up very much glucose.

      4. Add more small sticky notes on the pancreas to represent more β cell damage.

      5. Pour 5 glucose pieces on the balance and tip the balance.

      6. Release NO insulin into the blood stream.

Clear the model board. Please answer the questions about Scenario Four on your Student Sheet.

A person goes from a sedentary lifestyle to one that includes daily exercise. What happens?

Hint: Muscles can take up about five times as much glucose as liver and fat, and can use glucose during and after exercise even if no insulin is present. Muscles also burn glucose for energy.

1. 1. Pour about 15 glucose pieces on the balance, tip the balance, respond accordingly.

   2. Release five insulin into the blood stream.

   3. Place insulin onto each receptor on the liver, fat and muscle.

   4. Move 12 glucose into the liver, fat and muscle. The muscles can take up lots of glucose, so move more glucose into the muscles.

   5. Arrange the glucose in the muscle and liver into chains to represent stored glucose in the form of glycogen. Remove insulin from the receptors.

   6. Use two sticky notes to cover some of the insulin receptors to represent insulin resistance.

   7. Use a sticky note to cover up some of the pancreas to represent minor β cell damage.

   8. Pour about 15 more glucose pieces on the balance, tip the balance, respond accordingly.

   9. Release two insulin into the blood stream.

   10. Move most of the glucose into the muscle, even if no insulin is on the receptor. During and after exercise, glucose can enter muscles even without insulin present.

   11. The muscles are working hard and use glucose for energy during exercise. Remove glucose from the muscle. You may break apart one glucose piece to illustrate that it is involved in a chemical reaction during cellular respiration.

Clear the model board. Please answer the questions about Scenario Five on your Student Sheet.

It is 3:30 pm and you are sitting on your couch binge-watching your favorite show. You dig through the kitchen cupboard and find a bag of candy corn way in the back. You open it up and before you know it, you have eaten the whole bag

1. Pour about 20 glucose pieces on the balance, tip the balance, and respond accordingly.

2. In the presence of insulin, move the glucose into the cells in the model.

3. Arrange the glucose in the liver and muscle into chains to represent stored glucose in the form of glycogen.

The liver has an excess of glycogen so insulin stimulates enzymes to convert glucose into fatty acids. Spaghetti pieces represent fatty acids.

4. Replace 3 of the glucose molecules in the liver with 6 pieces of spaghetti.

5. Move the spaghetti from the liver to the blood stream and then into fat cells. Insulin increases fatty acid uptake in fat (adipose) cells.

The glucose in the fat cells can be converted to glycerol. Marshmallows represent glycerol.

6. Replace 2 glucose molecules in the fat cells with 2 marshmallows to represent glycerol.

7. Stab 3 spaghetti pieces into one side of each marshmallow to form a triglyceride, the main component of body fat. Insulin signaling stimulates triacylglycerol synthesis within the fat cells.

8. Keep the insulin on the receptors. Insulin inhibits the breakdown of triglycerides (lipolysis) so the triglycerides are stored in fat cells.

9. Repeat the steps above in the skeletal muscle by replacing 3 of the glucose molecules in the muscles with 6 pieces of spaghetti and converting 2 glucose into 2 marshmallows. Triglycerides are stored in skeletal muscle in the same way as in fat cells.

Triglycerides are the main component of body fat. They are made when your body needs to store excess calories. When insulin is bound to receptors on fat and skeletal muscle cells, it stimulates the uptake of triglycerides from the blood.

Clear the model board. Please answer the questions about Scenario Six on your Student Sheet.