Calculate the total volume of air inhaled during one minute during the highest velocity of the treadmill in this test, giving the units.

Outline the role of the parts of an alveolus in a human lung.

Evaluate which of the two biomarkers would be the most useful indicator of COPD severity.

Using the data presented in this question, explain the effect of hypoxia on the body.

Outline the process of inhalation.

The graph shows a spirometer trace of oxygen consumption when breathing at rest and during exercise.

[Source: Courtesy of Dr. Dafang Wang for his work at University of Utah.]

What explains the difference between the traces at regions X and Y on the graph?

A. At X, the internal intercostal muscles contract more than the external intercostal muscles.

B. At Y, the ribcage moves up and out more than at X.

C. At X, the diaphragm flattens more per breath than at Y.

D. At Y, the intercostal muscles contract more slowly than at X.

Using the data in the graph, deduce whether hypoxia increases or decreases the endurance of the rats’ diaphragm muscle.

Outline how ventilation rate could have been monitored in this study.

Other studies on pulmonary diseases have shown a wide variety of results. Apart from age, sex and severity of COPD, list two other factors that may explain the inconsistent results between studies.

Elastin is also an important component of other tissues such as arteries and ligaments. Evaluate how these other sources of elastin could affect the interpretation of the biomarker as an indicator of COPD.

Explain how a low FEV can be used to indicate emphysema.

Using all relevant data in the question, evaluate the effectiveness of the rats’ adaptation to hypoxia.

Explain the process of gas exchange taking place in the alveoli.

Hypoxia caused a 13 % increase in the surface area to volume ratio of the diaphragm. Suggest a reason for this change.

Muscle fibres are stimulated to contract by the binding of acetylcholine to receptors in their membranes and the subsequent depolarization.

Suggest a reason for increasing the concentration of sodium–potassium pumps in the membranes of diaphragm muscle fibres.

Discuss the advantages and disadvantages of using rats as models in this investigation.

Analyse the graph to obtain two conclusions about the concentration of sodium–potassium pumps.

Discuss whether measurements of desmosine concentration would be useful for monitoring changes in the health of a patient.