Chap 23

Question 0

2. List the two anatomical divisions of the respiratory system.

Answer 0

The two anatomical divisions of the respiratory system are the upper respiratory system and the lower respiratory system.

Question 1

1. Identify several functions of the respiratory system.

Answer 1

Functions of the respiratory system include providing an extensive surface area for gas exchange between blood and air, moving air to and from exchange surfaces, protecting exchange surfaces from environmental variations and pathogens, producing sounds, detecting olfactory stimuli, and indirectly assisting in blood volume regulation and blood pressure through the conversion of angiotensin I to angiotensin II.

Question 2

3. What membrane lines the conducting portion of the respiratory tract?

Answer 2

The respiratory mucosa lines the conducting portion of the respiratory tract.

Question 3

4. Name the structures of the upper respiratory system.

Answer 3

The upper respiratory system consists of the nose, nasal cavity, paranasal sinuses, and pharynx.

Question 4

5. Why is the vascularization of the nasal cavity important?

Answer 4

The rich vascularization to the nose delivers body heat to the nasal cavity, so inhaled air is warmed before it leaves the nasal cavity. The heat also evaporates moisture from the epithelium to humidify the incoming air.

Question 5

6. Why is the lining of the nasopharynx different from that of the oropharynx and the laryngopharynx?

Answer 5

The lining of the nasopharynx, which receives only air from the nasal cavity, is the same as that of the nasal cavity: a pseudostratified ciliated columnar epithelium. Because the oropharynx and laryngopharynx receive both air from the nasal cavity and potentially abrasive food from the oral cavity, they have a more highly protective lining: a stratified squamous epithelium like that of the skin.

Question 6

7. Identify the paired and unpaired cartilages associated with the larynx.

Answer 6

The unpaired laryngeal cartilages include the thyroid cartilage, cricoid cartilage, and epiglottis. The paired cartilages are teh arytenoid cartilages, corniculate cartilages, and cuneiform cartilages.

Question 7

8. What are the highly elastic vocal folds of the larynx better known as?

Answer 7

The highly elastic vocal folds of the larynx are better known as the vocal cords.

Question 8

9. When the tension in your vocal folds increases, what happens to the pitch of your voice?

Answer 8

When vocal fold tension increases, the pitch of the voices is raised.

Question 9

10. List functions of the trachea.

Answer 9

The trachea transports air between the larynx and primary bronchi; cilia and the mucus produced by epithelial cells also protect the respiratory tree by trapping inhaled debris and sweeping it toward the pharynx, where it is removed through coughing or swallowing.

Question 10

11. Why are the cartilages that reinforce the trachea C-shaped?

Answer 10

The tracheal cartilages are C-shaped to allow space for expansion of the esophagus when food or liquid is swallowed.

Question 11

12. If food accidentally enters the bronchi, in which bronchus is it more likely to lodge? Why?

Answer 11

Objects are more likely to be lodged in the right bronchus because it is slightly larger and more vertical than the left bronchus.

Question 12

13. What would happen to the alveoli if surfactant were not produced?

Answer 12

Without surfactant, the alveoli would collapse as a result of surface tension in the thin layer of water that moistens the alveolar surfaces.

Question 13

14. Trace the path air takes in flowing from the glottis to the respiratory membrane.

Answer 13

Air passing through the glottis flows into the larynx and through the trachea. From there, the air flows into a primary bronchus, which supplies the lungs. In the lungs, the air passes to bronchi, bronchioles, a terminal bronchiole, a respiratory bronchial, an alveolar duct, an alveolar sac, an alveolus, and ultimately to the respiratory membrane.

Question 14

15. Which arteries supply blood to the conducting portions and respiratory exchange surfaces of the lungs?

Answer 14

The pulmonary arteries supply the gas exchange surfaces; the external carotid arteries, the thyrocervical trunks, and the bronchial arteries supply the conducting portions of the respiratory system.

Question 15

16. List the functions of the pleura.

Answer 15

The pleura is a serous membrane that secretes pleural fluid, which lubricates the opposing parietal and visceral surfaces to prevent friction during breathing.

Question 16

17. Define external respiration and internal respiration.

Answer 16

External respiration includes all the process involved in the exchange of oxygen and carbon dioxide between the body’s interstitial fluids and the external environment.

Internal respiration is the absorption of oxygen and the release of carbon dioxide by the body’s cells.

Question 17

18. name the integrated steps involved in external respiration.

Answer 17

The integrated steps involved in external respiration are pulmonary ventilation (breathing), gas diffusion, and the transport of oxygen and carbon dioxide.

Question 18

19. Define compliance and identify the factors that affect it.

Answer 18

Compliance is the ease with which lungs expand. Factors affecting compliance include:

1. the connective tissue structure of the lungs
2. the level of surfactant production, and
3. the mobility of the thoracic cage

Question 19

20. Name the various measurable pulmonary volumes.

Answer 19

The pulmonary volumes are resting tidal volume (Vt), expiratory reserve volume (ERV), residual volume, and inspiratory reserve volume (IRV).

Question 20

21. Mar breaks a rib that punctures the chest wall on his left side. What do you expect will happen to his left lung as a result?

Answer 20

When the rib penetrates Mark’s chest wall, atmospheric air enters his thoracic cavity (a condition called pneumothorax), raising the pressure within the pleural cavity. As a result, the natural elasticity of the lung may cause the lung to collapse, a condition called atelectasis.

Question 21

22. In pneumonia, fluid accumulates in the alveoli of the lungs. How would this accumulation affect vital capacity?

Answer 21

Because the fluid produced in pneumonia take up space that would normally be occupied by air, vital capacity (the greatest amount of air that can be expelled from the lungs after taking the deepest breath possible) would decrease.

Question 22

23. Define Dalton’s law.

Answer 22

Dalton’s law states that each gas in a mixture exerts a pressure equal to its relative abundance.

Question 23

24. Define Henry’s law.

Answer 23

Henry’s law states that at a constant temperature, the quantity of a particular gas that will dissolve in a liquid is directly proportional to the partial pressure of that gas.

Question 24

25. Identify the three ways that carbon dioxide is transported in the bloodstream.

Answer 24

Carbon dioxide is transported in the bloodstream as carbonic acid, bound to hemoglobin, or dissolved in the plasma.

Question 25

26. As you exercise, hemoglobin releases more oxygen to active muscles than it does when those muscles are at rest. Why?

Answer 25

The combination of increased temperature and lower pH (from heat and acidic waste products generated b active skeletal muscles) causes hemoglobin to release more oxygen than when body is at rest.

Question 26

27. How would blockage of the trachea affect blood pH?

Answer 26

Blockage of the trachea would interfere with the body’s ability to gain oxygen and eliminate carbon dioxide. Becuase most carbon dioxide is transported in blood as bicarbonate ion formed from the dissociation of carbonic acid, an inability to eliminate carbon dioxide would result in an excess of hydrogen ions, which lowers blood pH.

Question 27

28. What effect does exciting the pneumotaxic centers have on respiration?

Answer 27

Exciting the pneumataxic centers would inhibit the inspiratory and apneustic centers, which would result in shorter and more rapid breaths.

Question 28

29. Ar peripheral chemoreceptors as sensitive to levels of carbon dioxide as they are to levels of oxygen?

Answer 28

Peripheral chemoreceptors are more sensitive to carbon dioxide levels than to oxygen levels. When carbon dioxide dissolves, it produces gydrogen ions, therby lowering pH and altering cell or tissue activity.

Question 29

30. Little Johnny is angry with his mother, so he tells her that he willhold his breath until he turns blue and dies. Should Johnny’s mother worry?

Answer 29

Johnny’s mother shouldn’t worry. When Johnny holds his breath, blood carbon dioxide levels increase, causing increased stimulation of the inspiratory center and forcing Johnny to breathe again.

Question 30

32. Identify the functional relationship between the respiratory system and all other systems.

Answer 30

The respiratory system provides oxygen and eliminates carbon dioxide for all body systems.

Question 31

33. Describe the functional relationship between the respiratory system and the lymphatic system.

Answer 31

The respiratory system provides alveolar phagocytes and respiratory defenses to trap pathogens and protect deeper tissues. Tonsils within the lymphatic system protect against respiratory infection and lymph drainage from the lungs mobilizes defenses to ward off infection.

Question 32

31. Name several age-related factors that affect the respiratory system.

Answer 32

Aging results in deterioration of elastic tissue (reducing compliance), arthritic changes in rib articulations, decreased flexibility at costal cartilages, decreased vital capacity, and some degree of emphysema.

Question 33

1. Identify the structures of the respiratory system in the following figure.

Answer 33

a. nasal cavity
b. pharynx
c. right lung
d. nose
e. larynx
f. trachea
g. bronchus
h. bronchioles
i. left lung

Question 34

2. Surfactant

Answer 34

d) helps prevent the alveoli from collapsing.

Question 35

3. The hard palate separates the

Answer 35

c) nasal cavity and the oral cavity.

Question 36

4. Air moves into the lungs becuase

Answer 36

a) the gas pressure in the lungs decreases with inspiration.

Question 37

5. 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

Answer 37

c) cough.

Question 38

6. When the diaphragm and external intercostal muscles contract,

Answer 38

c) intrapleural pressure decreases

Question 39

7. During the winter, Brad sleeps in a dorm room that lacks any humidifier for the heated air. In the morning he notices that his nose is “stuffy” similar to when he has a cold, but after showering and drinking some water, the stuffiness disappears until the next morning. What might be the cause of Brad’s nasal condition?

Answer 39

Since the air Brad is breathing is dry, large amounts of moisture are leaving the mucus in his respiratory tract to humidify inhaled air. Dying makes the mucus tacky and makes it difficult for the cilia to move, so mucus builds up, producing nasal congestion by morning. When Brad showers and drinks fluids, body water is replaced, so teh mucus loosens up and can be moved along as usual.

Question 40

8. Distinguish the structures of the upper respiratory system from those of the lower respiratory system.

Answer 40

The upper respiratory system consists of the nose, nasal cavity, paranasal sinuses, and pharynx. The lower respiratory system consists of the larynx, trachea, bronchi, bronchioles, and alveoli of the lungs.

Question 41

9. Name the three regions of the pharynx. Where is each region located?

Answer 41

The regions of the pharynx are the superior nasopharynx, where the nasal cavity opens into the pharynx; the middle oropharynx, posterior to the oral cavity; and the inferior laryngopharynx, which is posterior ot the hyoid bone and glottis.

Question 42

10. List the cartilages of the larynx. What are the functions of each?

Answer 42

The thyroid cartilage forms the anterior walls of the larynx; the cricoid cartilage protects the glottis and the entrance to the trachea; the epiglottis forms a lid over the glottis; the arytenoid cartilages and corniculate cartilages are involved int eh formation of sound; and the cuneiform cartilages are found in the folds of the larynx.

Question 43

11. What three integrated steps are involved in external respiration?

Answer 43

The steps of external respiration are:

a) pulmonary ventilation (breathing)
b) gas diffusion across the respiratory membrane and between blood and interstitial fluids
c) the transport of oxygen and carbon dioxide between alveolar and peripheral capillaries.

Question 44

12. What important physiological differences exist between fetal hemoglobin and maternal hemoglobin?

Answer 44

Fetal hemoglobin has a higher affinity for oxygen than does adult hemoglobin. Thus, it binds more of the oxygen that is present, enabling it to “steal” oxygen from the maternal hemoglobin.

Question 45

13. By what three ways is carbon dioxide transported in the bloodstream?

Answer 45

Carbon dioxide is transported in the blood as carbonic acid, bound to hemoglobin, and dissolved in the plasma.

Question 46

14. Which of the following does not occur in internal respiration?

Answer 46

C

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.

Question 47

15. Gas exchange at the respiratory membrane is efficient becuase

Answer 47

d)
- the differences in partial pressure are substantial
- the gases are liquid soluble
- the total surface are is large

Question 48

16. For any partial pressure of oxygen, if the concentration of 2,3-bisphosphoglycerate (BPG) increases,

Answer 48

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

Question 49

17. An increase in the partial pressure of carbon dioxide in arterial blood causes chemoreceptors to stimulate the respiratory centers, resulting in

Answer 49

b) an increased respiratory rate.

Question 50

18. Why is breathing through the nasal cavity more desirable than breathing through the mouth?

Answer 50

The nasal cavity cleanses, moistens, and warms inhaled air, whereas the mouth does not. Drier air entering through the mouth can irritate the trachea and cause throat soreness.

Question 51

19. How would you justify the statement “The bronchioles are to the respiratory system what the arterioles are to the cardiovascular system”?

Answer 51

Smooth muscle tissue in the walls of bronchioles allows changes in airway diameter (bronchodilation or bronchoconstriction), which provides control of the flow and distribution of air within the lungs, just as vasodilation and vasocaoconstriction of the arterioles control blood flow and blood distribution.

Question 52

20. How are pneumocytes type II involved with keeping the alveoli from collapsing?

Answer 52

Pneumocytes type II (septal cells) produce surfactant, which reduces surface tension in the fluid coating the alveolar surface. Without surfactant, the surface tension would be so high that the delicate alveli would collapse.

Question 53

21. How does pulmonary ventilation differ from alveolar ventilation, and what is the function of each type of ventilation?

Answer 53

Pulmonary ventilation, the physical movement of air into and out of the respiratory tract, maintains adequate alveolar ventilation. Alveolar ventilation, air movement into and our of the alveoli, preventis the buildup of carbon dioxide in the alveoli and ensures a continuous supply of oxygen that keeps pace with absorption by the blood stream.

Question 54

22. What is the significance of:
    a) Boyles’s law
    b) Dalton’s law
    c) Henry’s law
    to the process of respiration?

Answer 54

a) Boyle’s law describes the inverse relationship between gas pressure and volume: If volume decreases, pressure rises, if volume increases, pressure falls. It is the basis for the direction of air movement in the pulmonary ventilation.
b) Dalton’s law states that each of the gases that make up a mixture of gases contributes to the total pressure in proportion to its relative abundance; that is, all the partial pressures added together eual the total pressure exerted by the gas mixture. This relationship is the basis for the calculation of the partial pressures of oxygen and carbon dioxide, and their exchange between blood and alveolar air.
c) Henry’s law states that, at a given temperature, the amount of particular gas that dissolves in a liquid proportional to the partial pressure of that gas. Henry’s law underlies the diffusion of gases between capillaries, alveoli, and interstitial fluid.

Question 55

23. What happens to the process of respiration when a person is sneezing or coughing?

Answer 55

Both sneezing and coughing involve a temporary cessation of respiration, known as apnea.

Question 56

24. What are the differences between pulmonary volumes and respiratory capacities? How are pulmonary volumes and respiratory capacities determined?

Answer 56

Pulmonary volumes are determined experimentally and include resting tidal volume (averaging 500mL), expiratory reserve volume (approximately 1200mL), residual volume (averaging 1200mL), minimal volume (30-120 mL), and inspiratory reserve volume (approximately 3600mL). Respiratory capacities include inspiratory capacity, functional residual capacity, vital capacity, and total lung capacity. The difference between the two measures is that respiratory capacites are the sums of various pulmonary volumes.

Question 57

25. What is the functional difference between the dorsal respiratory group (DRG) and the ventral respiratory group (VRG) of the medulla oblongata?

Answer 57

The DRG is the inspiratory center that contains neurons that control lower motor neurons innervating the external intercostal muscles and the diaphragm. The DRG functions in every respiratory cycle, whether quiet or forced. The VRG functions only during forced respiration - active exhalation and maximal inhalation. The neurons involved with active exhalation are sometimes said to form an expiratory center.

Question 58

27. Mr. B. has had chronic advanced emphysema for 15years. While hospitalized with a respiratory infection, he goes into respiratory distress. Without thinking, his nurse immediately administers pure oxygen, which causes Mr. B. to stop breathing. Why?

Answer 58

A person with chronic emphysema has constantly elevated blood levels of P CO2 due to an inability to eliminate CO2 efficiently because physical damage to the lungs. Over time, the brain ignores the stimulatory signals produced by the increase CO2 and begins to rely on information from peripheral chemoreceptors to set the pace of breathing. (In other words, accommodation has set occurred.) The peripheral chemoreceptors also accommodate to elevate CO2 and respond primarily to the level of O2 in the blood, increasing breathing when O2 levels are high. When pure O2 was administered, chemoreceptors respond with fewer action potentials to the medulla oblongata, so Mr. B stopped breathing.

Question 59

28. Cary hyperventilates for several minutes before diving into a swimming pool. After he enters and begins swimming underwater, he blacks out and almost drowns. What caused this to happen?

Answer 59

Cary’s hyperventilation resulted in abnormally low P CO2. This reduced his urge to breathe, so he stayed under water longer, unaware that P O2 was dropping to the point of loss of consciousness.

Question 60

29. Why do individuals who are anemic generally not exhibit an increase in respiratory rate or tidal volume, even though their blood is not carrying enough oxygen?

Answer 60

In anemia, the blood’s ability to carry oxygen is decreased due to the lack of functional hemoglobin, red blood cells, or both. Anemia does not interfere with the exchange of carbon dioxide within the alveoli, nor with the amount of oxygen that will dissolve in the plasma. Because chemoreceptors respond to dissolved gasses and pH, as long as the pH and the concentrations of dissolved carbon dioxide and oxygen are normal, ventilation patterns should not change significantly.

Question 61

30. Doris has an obstruction of her right primary bronchus. As a result, how would you expect the oxygen-hemoglobin saturation curve for her right lung to compare with that for her left?

Answer 61

The obstruction in Doris’s right lung would prevent gas exchange. Thus, blood moving through the right lung would not be oxygenated and would retain carbon dioxide, which would lead to a lower blood pH than that of blood leaving the left lung. The lower pH for blood in the right lung would shift the oxygen - hemoglobin saturation curve to the left (the Bohr effect) as compared with the curve for the left lung.