Question

1. What is the function of surfactant?

To decrease compliance (stretchability)

To increase the radius of the bronchi

To decrease surface tension which prevents the alveoli from collapsing

2. Which of the following does NOT influence the loading reactions at the lungs?

Pulmonary edema

The amount of hemoglobin in the blood

The pO2 gradient across the respiratory membrane

Blood pH

3 Which of the following does NOT play a role in keeping the lungs inflated?

FEV1

Surfactant

Residual volume

Transpulmonary pressure gradient

4. H+ from lactic acid produced during anaerobic exercise stimulates peripheral chemoreceptors causing:

An increase in FEV1

A decrease in minute ventilation

A decrease in unloading at the tissues

An increase in respiratory rate

5. Why does a pneumonthorax cause the lungs to collapse?

a pneumothorax increases surface tension in the alveoli causing them to collapse

A pneumothorax abolishes the transpulmonary pressure gradient between the lungs and the intrapleural space allowing elastic recoil to pull the pleural membranes apart

A pneumothorax causes surfactant to leak out of the lungs causing the alveoli to collapse

Answers only :)

Answer 1

1. ANSWER: To decrease the surface tension which lrevents the lungs from collapsing.

Reason: Surfactant is a protein which lines the alveoli whose function is to reduce surface tension in the alveolar wall and to prevent the alveoli from collapsing.

2. ANSWER: blood ph.

3.ANSWER: FEV1.

Reason: FEV1 is the maximal amount of air that can be exhaled in one second. Hence it cannot play a role in maintaining lings in inflated state.

4. ANSWER: an increase in respiration rate.

Reason: Stimulation of peripheral chemoreceptors during exercise may increase the respiration rate of an individual.

5. ANSWER: pneumothorax abolishes the transpulmonary pressure gradient between lungs and intrapleural space allowing elastic recoil to pull the pleural membranes apart.