Gas exchange: Practice Questions

Which of the following describes a structural adaptation of the alveolar epithelium that facilitates a rapid rate of gas exchange in the human lung?

During gas exchange in the human respiratory system, the antagonistic interaction of muscles causes pressure changes in the thoracic cavity. Which of the following occurs during quiet, healthy inspiration?

Stomata play a critical role in the gas exchange of dicotyledonous plants. During times of water stress, the guard cells become flaccid and the stomata close. Which statement correctly identifies a functional compromise resulting from this action?

In the tracheal system of an insect, what is the role of the spiracles?

In dicotyledonous plants, the mesophyll layer is critical for gas exchange. Which structural feature of this tissue specifically facilitates the rapid diffusion of carbon dioxide to the photosynthesising cells?

Explain how the structure of the tracheal system in insects is adapted to provide a short diffusion distance for gas exchange.

Describe how the partial pressure of oxygen in the tracheoles of an insect is lowered during intense muscle contraction, and explain how this creates a faster rate of gas exchange.

The efficiency of gas exchange in bony fish is significantly enhanced by the anatomical arrangement of the gills.

a) Describe the gross structure of the fish gas exchange system, specifically mentioning filaments and lamellae. (2 points)
b) Explain how the counter-current principle ensures that the maximum amount of oxygen is extracted from the water into the blood. (3 points)

A specific species of desert beetle has a high metabolic rate and is highly active. To balance gas exchange with the need to minimize water loss, its tracheal system undergoes specific physiological changes.

a) Explain how the presence of spiracles and their ability to open and close serves as a functional compromise between gas exchange and water loss in terrestrial insects. (2 points)
b) During flight, the fluid at the ends of the tracheoles is drawn into the surrounding muscle tissues. Explain how this movement of fluid increases the rate of gas exchange. (2 points)