Gas Exchange (DP IB Biology: SL)

An alveolus has several features to allow efficient gas exchange.

Which row of the table below matches each feature of gas exchange to the correct label on the alveolus?

What is the function of pulmonary surfactant?

A scientist examines a cross section of the wall of a bronchus under an electron microscope. Which of the following would be observed?

1. Smooth muscle.
2. Cartilage cells.
3. Ciliated cells.

Which row of the table correctly describes a bronchiole?

Which set of conditions is required to allow the intake of air into the lungs during ventilation?

What is an example of a pair of antagonistic muscles?

Why is it difficult to show a causal link between a risk factor and a particular disease?

What is the correct sequence of events for the development of emphysema in the lungs?

1. Phagocytes release elastase to destroy bacteria trapped in lungs.
2. Alveolar walls break down.
3. Oxygen cannot diffuse into the blood quickly enough to sustain activity.
4. Elastase breaks down elastin reducing elasticity of the alveoli.
5. Alpha 1-antitrypsin cannot counteract high levels of elastase.

What conclusions can be drawn from the data in the graph?

The diagram shows a trace recorded from a spirometer.

Which label represents the tidal volume?

During a gas exchange investigation, measurements were recorded from four animals that were observed as they breathed normally over a period of 5 minutes. Note that the efficiency of gas exchange was the same in all four animals and that tidal volume refers to the volume of air that moves into the lungs with each normal breath.

Which animal had the highest oxygen intake during five minutes of normal breathing?

Which row of the table contains five correct statements about forced expiration?

Four patients, all male and in the age range 60-65, visited their family doctor complaining of breathing difficulties. The doctor asked each man a series of questions about his symptoms and lifestyle. 

Based upon the men's lifestyles and their lists of symptoms, which patient is at the highest risk of lung cancer?

Anti-smoking groups have conducted a long-running campaign to link smoking to lung cancer in a causal relationship. This relationship was finally proved in the British Doctors Study that ran from 1951-2001.

Which is not a factor that contributed to this causal link being proven?

Some of the effects of smoking are given below. 

1. Alveolar walls become less elastic.
2. Increased nerve impulse transmission occurs in parts of the brain.
3. Heart rate increases.
4. The risk of changes to genes involved in controlling the cell cycle increases.

Which row of the table contains the smoking-related causes of effects 1-4? Note that 'tar' in this context is a term used for the combination of insoluble and viscous chemicals found in tobacco smoke.