25 Study Guide

Considering the sequence of structure through which air enters the pulmonary system, the pharynx is to the trachea as the:
A. bronchioles are to the segmental bronchi.
B. alveoli are to the alveolar ducts.
C. alveolar ducts are to the respiratory bronchioles.
D. respiratory bronchioles are to the alveolar ducts.
E. All of the above are correct.

The cilia of the bronchial wall:
A. ingest bacteria.
B. trigger the sneeze reflex.
C. trap and remove bacteria.
D. propel mucus and trapped bacteria toward the oropharynx.
E. Both a and c are correct.

As the terminal bronchioles are approached:
A. the epithelium becomes thicker.
B. the epithelium becomes thinner.
C. mucus-producing glands increase.
D. the smooth muscle layer thickens.
E. cartilaginous support increases.

The left bronchus:
A. has a course more vertical than that on the right.
B. is more angled than the right.
C. is shorter and wider than the right.
D. has more bronchial wall layers than the right.
E. is symmetrical to the right.

The respiratory unit consists of:
A. cilia.
B. bronchiolar arteries and veins.
C. goblet cells and alveoli.
D. respiratory bronchioles and alveoli.
E. All of the above are correct.

Alveoli are excellent gas exchange units because of:
A. their large surface area.
B. a very thin epithelial layer.
C. extensive vascularization.
D. Both b and c are correct.
E. a, b, and c are correct.

Surfactant:
A. facilitates O₂ exchange.
B. produces nutrients for the alveoli.
C. permits air exchange between alveolar ducts.
D. facilitates alveolar expansion during inspiration.
E. All of the above are correct.

During expiration, which relationship is true?
A. As the lung pressure increases, the number of gas molecules increases.
B. As the partial pressure increases, less gas will dissolve in a liquid.
C. As the lung volume decreases, the number of gas molecules increases.
D. As the lung volume decreases, the pressure increases.

When the diaphragm and external intercostal contract:
A. the intrathoracic volume increases.
B. the intrathoracic pressure increases.
C. the intrathoracic volume decreases.
D. None of the above is correct.

Inspiratory reserve volume
A. amount of air remaining in lungs after a forced expiration
B. includes sum of tidal, expiratory reserve, and inspiratory reserve volumes
C. the extra air pushed out during a forced exhalation
D. taking an extra-deep breath of air just before diving

Vital capacity
a. amount of air remaining in lungs after a forced expiration
b. taking an extra-deep breath of air just before diving
c. includes sum of tidal, expiratory reserve, and inspiratory reserve volumes
d. the extra air pushed out during a forced exhalation

Oxygen diffusion from the alveolus to the alveolar capillary occurs because:
A. the PaO₂ is less in the capillary than in the alveolus.
B. the Pao₂ is greater in the atmosphere than in the arterial blood.
C. the PaO₂ is higher in the capillary than in the alveolus.
D. Oxygen diffuses faster than CO₂.

A shift to the right in the oxyhemoglobin dissociation curve:
A. prevents oxygen release at the cellular level.
B. causes oxygen to bind tighter to hemoglobin.
C. improves oxygen release and increases oxygen movement into the cells.
D. Both a and b are correct.
E. None of the above is correct.

In which sequence does PaO₂ progressively decrease?
A. body tissues, alveolar air, arterial blood
B. body tissues, arterial blood, alveolar air
C. atmospheric air, aortic blood, body tissues
D. blood in aorta, atmospheric air, body tissues

Most O₂ is carried in the blood ?, most CO₂ is carried in the blood ?.
A. bound to hemoglobin; bound to albumin
B. dissolved in plasma; associated with salt or an acid
C. bound to hemoglobin; associated with bicarbonate/carbonic acid
D. combined with albumin; associated with carbonic acid and hemoglobin

Alveoli are well-suited for diffusion of respiratory gases because:
A. they contain four thick layers, preventing air leakage.
B. they contain surfactant, which helps prevent alveolar collapse.
C. they are small and thus have a small total surface area.
D. vascularization is minimal, allowing greater air circulation.

Which ordinarily brings about the greatest increase in the rate of respiration?
A. increased arterial pH
B. excess carbon dioxide
C. increased O₂
D. a sudden rise in blood pressure

Given that the oxygen content of blood equals 1.34 ml of O₂ per gram of hemoglobin times the arterial oxygen saturation percentage, if hemoglobin concentration is 15 g/dl and arterial saturation is 98%, what is the arterial oxygen content?
A. 13.2 ml/dl of blood
B. 19.7 ml/dl of blood
C. 14.7 ml/dl of blood
D. None of the above is correct.

The major muscle(s) of inspiration is (are) the:
A. diaphragm.
B. sternocleidomastoid.
C. external intercostals.
D. internal intercostals.
E. Both a and c are correct.

Stretch receptors:
A. are sensitive to volume changes in the lung.
B. are located in airway smooth muscles.
C. decrease ventilatory rate when stimulated.
D. prevent lung overinflation when stimulated.
E. All of the above are correct.

Which of the following increases the respiratory rate?
A. increased PaCO₂, increased pH, decreased PaO₂
B. decreased PaCO₂, decreased pH, increased PaO₂
C. increased PaCO₂, decreased pH, decreased PaO₂
D. decreased PaCO₂, decreased pH, decreased PaO₂

The dorsal respiratory group (DRG) of neurons:
A. sets the automatic rhythm of respiration.
B. modifies the rhythm of respiration.
C. is active when increased ventilation is required.
D. None of the above is correct.

PaCO₂ of 40 mm Hg
a. arterial blood
b. mixed venous blood

Oxygen saturation of 70%
a. arterial blood
b. mixed venous blood

Oxygen content of blood of 19 to 20 ml/dl
a. arterial blood
b. mixed venous blood