6.4 Gas Exchange

1.Which type of cell is specialized to facilitate gas exchange?

2. Cladograms can be created by comparing DNA or protein sequences. The cladogram on the left is based on DNA sequences and the cladogram on the right is based on comparing protein sequences. What is the reason that cladograms based on DNA sequences are more reliable predictors of the phylogenetic relationship of species than cladograms based on protein sequences?

3. The bacterium Neisseria gonorrhoeae causes infections related to the human reproductive system. The graph shows the percentage of samples in which this bacterium showed resistance to six antibiotics over a period of ten years. What is a possible explanation for the total percentage resistance being larger than 100% in 2010?

4. Where does gas exchange occur in the lungs?  

5. The graph shows the ventilation rate and the oxygen consumption of a subject before, during and after a period of exercise. Which could be a reason for the oxygen consumption to remain high for some time after the end of the period of exercise?

6. What is the purpose of pulmonary surfactant?

7. Which conditions are correct for inspiration?

8. What changes take place in the thorax during inhalation?

9. The image shows a section of the human respiratory system. Which letter identifies a bronchiole?

10. What muscle actions cause air to be expelled from the lungs?

11. What changes occur in the thorax of a mammal when the external intercostal muscles and diaphragm muscles contract?

12. Which statement describes the movements of the rib cage during inhalation of air?

13. What is a feature of alveoli?

14. The diagram shows the ventilation system in humans. What is the function of the structure labelled X?

15. What occurs during the process of ventilation?

16. What normally prevents the membranes of the alveoli from sticking together during expiration?

17. What is the function of the structure labelled X?

18. Which of the following features of the alveoli adapt them to gaseous exchange? I.     Single layer of cells II.   Film of moisture III. Dense network of capillaries

19. What happens to the external and internal intercostal muscles and diaphragm when inhaling?

20. Which muscles contract to cause air to pass into the lungs through the trachea?

21. What change occurs to the pressure and volume of the lungs when the external intercostal muscles contract?

22. What feature of alveoli adapts them to efficient gas exchange?

23. Which muscle action is associated with an increase in the volume of the thoracic cavity when breathing in?