AQA GCSE Physical Education: The Cardiovascular & Respiratory Systems

Marcus is a 1500 m runner. As he begins his race, blood is redistributed around his body so that a much greater share goes to his working leg muscles. This change is brought about by the vascular shunt mechanism.

Explain how the vascular shunt mechanism redistributes blood during Marcus's race, and explain why this redistribution benefits his performance. In your answer refer to the role of arterioles, vasoconstriction and vasodilation. (6 marks)

While exercising, a cyclist has a heart rate of 160 bpm and a stroke volume of 120 ml per beat.

(a) Calculate the cyclist's cardiac output during exercise. Use $Q = \text{SV} \times \text{HR}$Q=SV×HR. Give your answer in litres per minute and show your working. (2 marks)

(b) The cyclist's resting cardiac output is 5.4 l/min. Using your answer to part (a), calculate how many times greater their cardiac output is during exercise than at rest. (2 marks)

A spirometer is used to measure the lung volumes of a games player at rest. The results are shown below.

(a) Using the data, calculate the player's vital capacity. (Vital capacity = tidal volume + inspiratory reserve volume + expiratory reserve volume.) (2 marks)

(b) State why the residual volume in the table cannot be measured directly by a spirometer. (1 mark)

Gaseous exchange takes place at the alveoli in the lungs.

(a) Name the gas that moves from the alveoli into the blood, and the gas that moves from the blood into the alveoli. (2 marks)

(b) State one structural feature of the alveoli that makes them well suited to gaseous exchange. (1 mark)

Arteries and veins are two types of blood vessel with different structures.

State two ways in which the structure of an artery differs from the structure of a vein. (2 marks)

Name the main muscle of breathing that contracts and flattens to help draw air into the lungs during inspiration. (1 mark)