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Questions

1. Identify the equation to work out cardiac output (Q).
   • A) stroke volume × heart rate
   • B) blood pressure × heart rate
   • C) tidal volume × stroke volume
   • D) blood pressure × stroke volume
2. Calculate the exercising cardiac output for a 10 km runner whose heart rate increases to 180 bpm and stroke volume increases to 120 ml. (2)
3. Identify the muscle that forms an antagonistic pair with the triceps. (1)
4. Describe the action of the diaphragm when breathing in. (2)
5. Using the evidence from the graph below discuss how the cardiovascular system adapts to long term aerobic exercise participation. (8)

Answers

1. A
2. Q = HR x SV or 180 x 120 which equals Q = 21600 ml or 21.6l
3. Biceps
4. The diaphragm contracts (1) and flattens (1)
5. Answer to include:
   • decreased resting BP
   • cardiac hypertrophy – increased stroke volume (SV), increased cardiac output (Q), decreased resting heart rate (HR) , increased max Q, increased HR reserve means the athlete can train at the same intensity at lower HR
   • capillarisation around the alveoli and skeletal muscle means greater O₂ diffusion
   • increased strength of respiratory muscles, increased vital capacity, decreased breathing frequency (f), decreased tidal volume means greater amount of O₂ available to working muscle
   • increased red blood cell production, increased haemoglobin level, increased O₂ carrying capacity, increased gaseous exchange, means greater O₂ carrying capacity