Describe the functions of the main blood vessels connecting the heart and the lungs.

Explain the mechanics of inhalation in the lungs during exercise.

pulmonary artery goes from heart to lungs ✔

pulmonary artery carries deoxygenated blood ✔

pulmonary vein goes from lungs to heart ✔

pulmonary vein carries oxygenated blood ✔

Award [2 max] for each.

Award [2 max] if no reference to pulmonary.

Award no mark if there is no reference to the type of blood vessel.

diaphragm and <external> intercostal muscles contract <more forcefully> ✔

causing the rib cage to move <further> upwards and outwards ✔

with assistance of the accessory muscles, e.g. scaleni, sternocleidomastoid, deltoids, pectoralis ✔

therefore increasing the thoracic volume ✔

therefore reducing the thoracic pressure ✔

causes air to rush in <faster due to a greater pressure difference> ✔

increase of the depth of inhalation <per breath> ✔

increase of the frequency/rate of inhalation <per minute> ✔

Award [3 max] if no reference to mechanics of inhalation during exercise.

As a topic area, candidates were either well-prepared or completely off the mark. Some candidates struggled to make reference to the specific blood vessels or even blood vessels at all.

Many candidates were able to achieve 3 of the 4 marks. However, very few made reference to the changes in mechanics due to exercise. Many candidates described how ventilatory control occurs, rather than focusing on the specific mechanics of inhalation. However, there were also a large number of candidates who were ill-prepared for this question and unable to provide any response worth of credit.