Anatomy and Physiology of Animals/Respiratory System/Test Yourself Answers

1. What is meant by the phrase “gas exchange”?
 * Gas exchange is the addition of oxygen to the blood and the removal of carbon dioxide.

2. Where does gas exchange take place?
 * Gas exchange takes place in the alveoli of the lungs.

3. What is the process by which oxygen moves from the alveoli into the blood?
 * Oxygen moves from the alveoli into the blood by diffusion.

4. Why does this process occur?
 * This process occurs because oxygen is at a much higher concentration in the alveoli than in the blood. Diffusion always occurs from a high to low concentration.

5. How does the structure of the alveoli make gas exchange efficient?
 * The thin walls of the alveoli and the capillaries give only a small distance for the oxygen and carbon dioxide to diffuse across making gas exchange efficient.
 * 6. How is oxygen carried in the blood?
 * Oxygen is carried in the blood combined with haemoglobin in the red blood cells.

7. List the structures that air passes on its way from the nose to the alveoli:
 * On its way to the alveoli of the lungs air travels through the nasal cavity, pharynx, larynx, trachea, bronchi and bronchioles.

8. What is the function of the mucous and cilia lining the respiratory passages?
 * The mucus and cilia in the respiratory passages trap dust particles and transport them to the mouth and nose for expulsion.

9. How do movements of the ribs and diaphragm bring about inspiration? Circle the correct statement below.


 * b) The diaphragm flattens and ribs move up and out.

10. What is the function of the epiglottis?
 * The epiglottis closes the larynx during swallowing so that food cannot enter the trachea.

11. What controls the rate of breathing?
 * The concentration of carbon dioxide in the blood controls the rate of breathing.