Standard mode uses checkpoints, data interpretation and short explanations.
School model: adrenaline raises glucose during exercise, insulin lowers it after exercise.
Normal response returns close to baseline in about 10 to 15 minutes.
Answer the prediction to unlock Start Exercise.
Use this tab to stop students just watching the line. The tasks change by difficulty.
This keeps the assessed MYP5 idea clear, but it also gives a more accurate note for students who ask about insulin during exercise.
Assessed idea: during exercise, adrenaline is released by the adrenal glands. It signals the liver to release glucose into the blood. After exercise, insulin from the pancreas helps lower blood glucose back towards the set point by making cells take up glucose and storing excess glucose as glycogen.
The nervous system detects activity quickly. The adrenal glands release adrenaline into the blood. Adrenaline reaches the liver and causes glycogen to break down into glucose. Blood glucose rises so working muscles have more glucose available for respiration.
For this course, you can use the simple model: adrenaline raises glucose during exercise and insulin lowers it after exercise. In a more realistic model, insulin does not disappear. Some is still present, but insulin secretion is usually reduced during exercise while adrenaline and sympathetic activity are high. This helps prevent glucose being lowered too quickly while muscles need fuel.
When exercise stops, adrenaline falls. If blood glucose is above the set point, the pancreas releases more insulin. Insulin causes body cells to take up glucose and causes the liver to store glucose as glycogen. This is negative feedback because the response reverses the rise and returns blood glucose towards normal.
Medium intensity starts at 4.8 mmol/L and rises to 6.5 mmol/L.
Step 1: Increase = peak value - resting value
Step 2: Increase = 6.5 - 4.8 = 1.7 mmol/L
Step 3: Blood glucose rose because adrenaline caused the liver to release glucose into the blood.
| Adrenaline | Insulin | |
|---|---|---|
| Released by | Adrenal glands | Pancreas |
| Main timing | During exercise, stress or fear | When blood glucose is above the set point |
| Effect | Raises blood glucose | Lowers blood glucose |
| How | Liver releases glucose from glycogen | Cells take up glucose, liver stores glucose as glycogen |
Run each intensity and copy the values into your practical comparison. The 10 min value is captured 10 minutes after you press Stop Exercise, not 10 minutes after the model starts.
| Stage | Low intensity | Medium intensity | High intensity |
|---|---|---|---|
| Before exercise | - | - | - |
| Immediately after exercise | - | - | - |
| 10 min after stopping exercise | - | - | - |
1. Describe the pattern using numbers.
2. Explain the rise using adrenaline, liver, glycogen and glucose.
3. Explain the fall using insulin, pancreas, cells and negative feedback.
4. Compare this model to your heart rate practical. Why are both useful during exercise?
5. Challenge: identify one limitation of this model.