Chapter 15 - Respiratory System

Question 1

Characteristics of olfactory epithelium include which one of the following?
(A) It is located in the inferior region of the nasal cavity.
(B) It is classified as simple columnar.
(C) It has an underlying lamina propria
containing mucous glands.
(D) It has modified cilia, which act as receptors for odor.
(E) It is unable to regenerate.

Answer 1

D. The olfactory epithelium possesses nonmotile cilia, which act as receptors for odor. They are extensions of the bipolar nerve cells that form part of this tall, pseudostratified epithelium located in the roof of the nasal cavity. Bowman glands, which lie in the lamina propria be­ neath this epithelium, produce a watery secretion, which moistens the olfactory surface (see Chapter 15 II A).

Question 2

Which of the following statements concern­
ing terminal bronchioles is true?
(A) They are part of the conducting portion of the respiratory system.
(B) They function in gas exchange.
(C) They do not contain ciliated cells.
(D) They have cartilage plates present in their
walls.
(E) They do not contain secretory cells.

Answer 2

A. Terminal bronchioles are the most distal components of the conducting portion of the respiratory system. They lack alveoli and thus do not function in gas exchange. They are lined by an epithelium composed of two cell types: secretory (Clara) cells and ciliated cells. Cartilage is not present in bronchioles (see Chapter 15 II F).

Question 3

The trachea possesses which one of the
following components?
(A) Irregular cartilage plates in its wall
(B) Skeletal muscle in its wall
(C) An epithelium containing onlytwo cell types
(D) A thick basement membrane underlying
its epithelium
(E) Bowman glands in its lamina propria

Answer 3

D. The pseudostratified ciliated columnar epithelium lining the trachea rests on a thick base­ ment membrane and contains five cell types. The trachea possesses C-shaped cartilages with smooth muscle (the trachealis) extending between their ends. Bowman glands are found only in the nasal cavity and produce a thin watery secretion (see Chapter 15 II D).

Question 4

Which of the following statements concerning respiratory bronchioles is true?
(A) No gas exchange occurs in them.
(B) They do not have alveoli forming part of
their wall.
(C) They contain goblet cells in their lining
epithelium.
(D) They are included in the conducting
portion of the respiratory system.
(E) Ciliated cells comprise a portion of their lining epithelium.

Answer 4

E. Respiratory bronchioles have alveoli interrupting their walls, so some gas exchange takes place at this level. Their remaining walls are lined by a simple cuboidal epithelium consisting of Clara cells and ciliated cells. Respiratory bronchioles are categorized as part of the respiratory portion of the system (see Chapter 15 III A).

Question 5

True statements about asthma include which one of the following?
(A) It is due to a loss of lung elasticity.
(B) It eventually causes the lungs to expand
and leads to a barrel chest.
(C) It is associated with difficulty expiring air from the lungs.
(D) It may be helped by gene therapy using recombinant a1-antitrypsin.
(E) It is usually not associated with inflammation.

Answer 5

C. Asthma results from the constriction of smooth muscle in the bronchioles, which de­ creases their diameter and makes the expiration of air very difficult. Mucus accumulates in the airways, and inflammatory cells invade the bronchiolar walls (see Chapter 15 II F Clinical Considerations).

Question 6

Which of the following statements concerning alveolar macrophages is true?
(A) They secrete a1-antitrypsin.
(B) They secrete elastase.
(C) They originate from blood neutrophils.
(D) They may play a role in causing hyaline
membrane disease.
(E) They secrete small amounts of surfactant.

Answer 6

B. Alveolar macrophages secrete elastase. Normally, a1-antitrypsin, a serum protein, interacts with elastase, thereby protecting the lung against damage that may lead to emphysema. Alveolar macrophages, like all macrophages, arise from blood monocytes; they do not secrete surfactant; and they are unrelated to the pathogenesis of hyaline membrane disease (see Chapter 15 III D Clinical Considerations).

Question 7

Which one of the following disorders may in some cases be successfully treated with antielastase (a1-antitrypsin}?
(A) Asbestosis
(B) Asthma
(C) Carbon monoxide poisoning
(D) Emphysema
(E) Hyaline membrane disease

Answer 7

D. Hereditary forms of emphysema are now being treated with recombinant a1-antitrypsin, which has antielastase activity (see Chapter 15 III D Clinical Considerations).

Question 8

Which one of the following is characterized by interstitial pulmonary fibrosis?
(A) Asbestosis
(B) Asthma
(C) Carbon monoxide poisoning
(D) Emphysema
(E) Hyaline membrane disease

Answer 8

A. Inhaling asbestos fibers causes interstitial pulmonary fibrosis in the walls of respiratory bronchioles, alveolar ducts, and alveoli. Asbestos bodies are a classic feature of asbestosis. After prolonged heavy exposure to asbestos, this disease may progress to mesothelioma (a malignant tumor) (see Chapter 15 III D Clinical Considerations).

Question 9

Which one ofthe following is associated with a barrel chest?
(A) Asbestosis
(B) Asthma
(C) Carbon monoxide poisoning
(D) Emphysema
(E) Hyaline membrane disease

Answer 9

D. A loss of lung elasticity in emphysema makes it difficult for the lungs to recoil normally during expiration. The lungs and thoracic cavity enlarge, producing a barrel chest (see Chapter 15 III D Clinical Considerations).

Question 10

Which one ofthe following is frequently
treated successfully with glucocorticoids?
(A) Asbestosis
(B) Asthma
(C) Carbon monoxide poisoning
(D) Emphysema
(E) Hyaline membrane disease

Answer 10

E. Glucocorticoids, which stimulate synthesis of pulmonary surfactant, are often administered to the expectant mother a few days prior to delivery to prevent or alleviate hyaline membrane disease in the premature infant (see Chapter 15 III D Clinical Considerations).