A cyclist ingests a sports drink containing carbohydrates and electrolytes during hour three of a four-hour training ride.
Explain how the digestive and endocrine systems interact with the circulatory and respiratory systems to maintain performance during this prolonged exercise. (5 marks)
--- 15 WORK AREA LINES (style=lined) ---
Show Answers Only
Sample Answer
Digestive-Circulatory Interaction:
- Sports drink carbohydrates absorb rapidly in the small intestine.
- As a result, blood glucose levels rise to support continued muscle function.
- This enables the circulatory system to deliver fuel while electrolytes maintain fluid balance.
Endocrine-Circulatory Interaction:
- Insulin release regulates glucose uptake from blood into muscle cells.
- This hormonal control ensures steady energy delivery via circulation.
- When blood glucose drops, glucagon triggers liver glucose release into bloodstream.
Circulatory-Respiratory Interaction:
- Heart rate and breathing rate increase together during intense cycling.
- Consequently, oxygen-rich blood reaches working muscles efficiently.
- Vasodilation in muscles combined with increased ventilation maximises oxygen delivery.
All Systems Working Together:
- Digestive absorption provides fuel while endocrine hormones regulate its use.
- These processes enable circulatory and respiratory systems to maintain energy production.
- Therefore, all four systems coordinate to sustain performance in the final hour.
Show Worked Solution
Sample Answer
Digestive-Circulatory Interaction:
- Sports drink carbohydrates absorb rapidly in the small intestine.
- As a result, blood glucose levels rise to support continued muscle function.
- This enables the circulatory system to deliver fuel while electrolytes maintain fluid balance.
Endocrine-Circulatory Interaction:
- Insulin release regulates glucose uptake from blood into muscle cells.
- This hormonal control ensures steady energy delivery via circulation.
- When blood glucose drops, glucagon triggers liver glucose release into bloodstream.
Circulatory-Respiratory Interaction:
- Heart rate and breathing rate increase together during intense cycling.
- Consequently, oxygen-rich blood reaches working muscles efficiently.
- Vasodilation in muscles combined with increased ventilation maximises oxygen delivery.
All Systems Working Together:
- Digestive absorption provides fuel while endocrine hormones regulate its use.
- These processes enable circulatory and respiratory systems to maintain energy production.
- Therefore, all four systems coordinate to sustain performance in the final hour.