End of Chapter 23 Questions

2. The hard palate separates the (a) nasal cavity from the larynx (b) left and right sides of the nasal cavity (c) nasal cavity and the oral cavity (d) nostrils from the choanae (e) soft palate from the nasal cavity.

(c) nasal cavity and the oral cavity

3. Air moves into the lungs because (a) the gas pressure in the lungs is less than atmospheric pressure (b) the volume of the lungs decreases with inspiration (c) the thorax is muscular (d) contraction of the diaphragm decreases the volume of the thoracic cavity (e) the respiratory control center initiates active expansion of the thorax.

(a) the gas pressure in the lungs is less than atmospheric pressure

17. An increase in the partial pressure of carbon dioxide in arterial blood causes chemoreceptors to stimulate the respiratory centers, resulting in: (a) a decreased respiratory rate (b) an increased respiratory rate (c) hypocapnia (d) hypercapnia.

(b) an increased respiratory rate

14. Which of the following does not occur in internal respiration? (a) Oxygen diffuses from the blood to the interstitial spaces. (b) Carbon dioxide diffuses from the interstitial spaces to the blood. (c) Hemoglobin binds more oxygen. (d) Bicarbonate ions are formed in red blood cells. (e) Chloride ions diffuse into red blood cells as bicarbonate ions diffuse out.

(c) Hemoglobin binds more oxygen.

4. The glottis closes partway through an exhalation. The abdominal and internal intercostal muscles then contract suddenly, creating pressure that blasts the air out of the respiratory passages. This describes a: (a) sneeze (b) hiccough (c) cough (d) laryngeal spasm (e) gag.

(c) cough

5. When the diaphragm and external intercostal muscles contract: (a) exhalation occurs (b) intrapulmonary pressure increases (c) intrapleural pressure decreases (d) the volume of the lungs decreases (e) the size of the thoracic cavity increases.

(c) intrapleural pressure decreases

16. For any partial pressure of oxygen, if the concentration of 2,3- bisphosphoglycerate (BPG) increases: (a) the amount of oxygen released by hemoglobin will decrease (b) the oxygen levels in hemoglobin will be unaffected (c) the amount of oxygen released by hemoglobin will increase (d) the amount of carbon dioxide carried by hemoglobin will increase.

(c) the amount of oxygen released by hemoglobin will increase

1. Surfactant: (a) protects the surface of the lungs (b) phagocytizes small particulates (c) replaces mucus in the alveoli (d) helps prevent the alveoli from collapsing (e) is not found in healthy lung tissue.

(d) helps prevent the alveoli from collapsing

15. Gas exchange at the blood air barrier is efficient because (a) the differences in partial pressure are substantial (b) the gases are lipid soluble (c) the total surface area is large (d) of all of these.

(d) of all of these.