Chapter 34: Structure and Function of the Pulmonary System

Hypoventilation that results in the retention of carbon dioxide will stimulate which receptors in an attempt to maintain a normal homeostatic state? a. Irritant receptors b. Central chemoreceptors c. Peripheral chemoreceptors d. Stretch receptors

ANS: B Central chemoreceptors indirectly monitor arterial blood by sensing changes in the pH of cerebrospinal fluid (CSF).

Which substances cause airway epithelium to constrict? a. Epinephrine and acetylcholine b. Histamine and prostaglandin c. Bradykinin and thromboxane A d. Leukotrienes and prostacyclin

ANS: B Constriction occurs if the irritant receptors in the airway epithelium are stimulated by irritants in inspired air, by endogenous substances (e.g., histamine, serotonin, prostaglandins), by many drugs, and by humoral substances.

Which receptors are located in the smooth muscles of airways? a. Central chemoreceptors b. Stretch receptors c. Peripheral chemoreceptors d. J-receptors

ANS: B Of the options available, only the stretch receptors are located in the smooth muscles of airways.

Which term is used to identify the movement of gas and air into and out of the lungs? a. Perfusion b. Ventilation c. Respiration d. Diffusion

ANS: B Of the options available, ventilation is the only term used to identify the mechanical movement of gas or air into and out of the lungs.

How is most of the oxygen in the blood transported? a. Dissolved in plasma b. Bound to hemoglobin c. In the form of carbon dioxide (CO2) d. Bound to protein

ANS: B Oxygen is transported in the blood in two forms. A small amount dissolves in plasma, and the remainder binds to hemoglobin molecules.

Which describes the pressure in the pleural space? a. Atmospheric b. Below atmospheric c. Above atmospheric d. Variable

ANS: B Pressure in the pleural space is usually negative or subatmospheric (−4 to −10 mm Hg).

What is the purpose of the spirometry measurement? a. To evaluate the cause of hypoxia b. To measure the volume and flow rate during forced expiration c. To measures the gas diffusion rate at the alveolocapillary membrane d. To determine pH and oxygen and carbon dioxide concentrations

ANS: B Spirometry measures volume and flow rate during forced expiration.

When an individual aspirates food particles, where would the nurse expect to hear decreased or absent breath sounds? a. Left lung b. Right lung c. Trachea d. Carina

ANS: B The right mainstem bronchus extends from the trachea more vertically than the left main bronchus; therefore aspirated fluids or foreign particles tend to enter the right lung rather than the left or any of the other locations listed.

Air passage among alveoli is collateral and evenly distributed because of the function of which structures? a. Type I alveolar cells b. Pores of Kohn c. Acinus pores d. Alveolar pores

ANS: B Tiny passages called pores of Kohn permit some air to pass through the septa from alveolus to alveolus, promoting collateral ventilation and even distribution of air among the alveoli.

Which structures secrete surfactant? a. Type I alveolar cells b. Type II alveolar cells c. Alveolar macrophages d. Stretch receptors

ANS: B Two major types of epithelial cells appear in the alveolus. Type I alveolar cells provide structure, and type II alveolar cells secrete surfactant,

Stretch receptors and peripheral chemoreceptors send afferent impulses regarding ventilation to which location in the brain? a. Pneumotaxic center in the pons b. Apneustic center in the pons c. Dorsal respiratory group (DRG) in the medulla oblongata d. Ventral respiratory group (VRG) in the medulla oblongata

ANS: C The respiratory center is made up of several groups of neurons located bilaterally in the brainstem: the DRG, the VRG, the pneumotaxic center, and the apneustic center.

What pulmonary defense mechanism propels a mucous blanket that entraps particles moving toward the oropharynx? a. Nasal turbinates b. Alveolar macrophages c. Cilia d. Irritant receptors on the nares

ANS: C The submucosal glands of the bronchial lining produce mucus, contributing to the mucous blanket that covers the bronchial epithelium.

Where does the tracheal bifurcation occur? a. Larynx b. Bronchi c. Carina d. Nasopharynx

ANS: C The trachea, which is supported by U-shaped cartilage, connects the larynx to the bronchi, the conducting airways of the lungs. The trachea divides into the two main airways, or bronchi, at the carina

An increase in surface tension caused by decreased surfactant production results in which alteration? a. Decrease in alveolar macrophage production b. Increase in lung compliance c. Decrease in alveoli collapse d. Increase in alveoli fluid collection

ANS: D The decrease in surface tension caused by surfactant is also responsible for keeping the alveoli free of fluid.

Which receptors are located in the aortic bodies, aortic arch, and carotid bodies? a. Central chemoreceptors b. Stretch receptors c. J-receptors d. Peripheral chemoreceptors

ANS: D peripheral chemoreceptors are located in the aortic bodies, aortic arch, and carotid bodies at the bifurcation of the carotids, near the baroreceptors.

The adequacy of a person's alveolar ventilation is assessed best by monitoring which mechanism? a. Ventilatory rate b. Ventilatory pattern c. Respiratory effort d. Arterial blood gas

ANS: D Observation of the ventilatory rate, pattern, or effort cannot determine the adequacy of alveolar ventilation.

What is the most important cause of pulmonary artery constriction? a. Low alveolar partial pressure of arterial oxygen (PaO2) b. Hyperventilation c. Respiratory alkalosis d. Epinephrine

ANS: A The most important cause of pulmonary artery constriction is a low alveolar PaO2.

Aspiration is most likely to occur in the right mainstem bronchus because it: a. Extends vertically from the trachea. b. Is narrower than the left mainstem bronchus. c. Comes into contact with food and drink first. d. Is located at the site where the bronchi bifurcate.

ANS: A The right mainstem bronchus extends from the trachea more vertically than the left mainstem bronchus; therefore aspirated fluids or foreign particles tend to enter the right lung rather than the left.

If a patient develops acidosis, the nurse would expect the oxyhemoglobin dissociation curve to react in which manner? a. Shift to the right, causing more oxygen (O2) to be released to the cells b. Shift to the left, allowing less O2 to be released to the cells c. Show no change, allowing the O2 concentration to remain stable d. Show dramatic fluctuation, allowing the O2 concentration to increase

ANS: A A shift to the right depicts hemoglobin's decreased affinity for O2 or an increase in the ease with which oxyhemoglobin dissociates and O2 moves into the cells.

The lung is innervated by the parasympathetic nervous system via which nerve? a. Vagus b. Phrenic c. Brachial d. Pectoral

ANS: A Fibers of the parasympathetic division of the autonomic nervous system (ANS) travel only in the vagus nerve to the lung.

The sternocleidomastoid and scalene muscles are referred to as which group? a. Diaphragmatic muscles b. Muscles of expiration c. Intercostal muscles d. Muscles of inspiration

ANS: A The accessory muscles of inspiration are the sternocleidomastoid and scalene muscles.

Which part of the brainstem provides basic automatic rhythm of respiration by sending efferent impulses to the diaphragm and intercostal muscles? a. Dorsal respiratory group (DRG) b. Ventral respiratory group c. Pneumotaxic center d. Apneustic center

ANS: A The basic automatic rhythm of respiration is set by the DRG, a cluster of inspiratory nerve cells located in the medulla that sends efferent impulses to the diaphragm and inspiratory intercostal muscles.

What are the effects of aging on the pulmonary system? a. Decreased chest wall compliance b. Decreased lung recoil c. Reduced ventilatory reserve d. Decreased partial pressure of arterial oxygen (PaO2) e. Reduced respiratory rate

ANS: A, B, C, D Aging affects the mechanical aspects of ventilation by decreasing chest wall compliance and elastic recoil of the lungs.

Regarding the respiratory process referred to as remodeling, which statements are true? (Select all that apply.) a. Remodeling involves the vascular walls. b. Scarring and thickening occurs during this respiratory process. c. Remodeling results in a permanent change. d. Pulmonary artery hypotension results. e. Remodeling increases blood flow resistance.

ANS: A, B, C, E Remodeling is a process by which the vascular wall becomes scarred and thickened, thus resulting in permanent decreases in luminal diameter, increased resistance to blood flow, and permanent pulmonary artery hypertension.

Which structures belong to the upper conduction airway? (Select all that apply.) a. Oropharynx b. Larynx c. Nasopharynx d. Trachea e. Bronchi

ANS: A, C The nasopharynx, oropharynx, and related structures are often called the upper airway.

How is most carbon dioxide (CO2) in the blood transported? a. Attached to oxygen b. In the form of bicarbonate c. Combined with albumin d. Dissolved in the plasma

ANS: B Approximately 60% of the CO2 in venous blood and 90% of the CO2 in arterial blood are carried in the form of bicarbonate.

Decreased lung compliance means that the lungs are demonstrating which characteristic? a. Difficult deflation b. Easy inflation c. Stiffness d. Inability to diffuse oxygen

ANS: C A decrease in compliance indicates that the lungs or chest wall is abnormally stiff or difficult to inflate.

What event is characteristic of the function in Zone 1 of the lung? a. Blood flow through the pulmonary capillary bed increases in regular increments. b. Alveolar pressure is greater than venous pressure but not greater than arterial pressure. c. The capillary bed collapses, and normal blood flow ceases. d. Blood

ANS: C Alveolar pressure exceeds pulmonary arterial and venous pressures in Zone 1. The capillary bed collapses, and normal blood flow ceases.

Where in the lung does gas exchange occur? a. Trachea b. Segmental bronchi c. Alveolocapillary membrane d. Main bronchus

ANS: C Gas exchange occurs only across the alveolocapillary membrane.

Which structure is not associated with any lymphatic vessels? a. Trachea b. Bronchi c. Acinus d. Terminal bronchioles

ANS: C No lymphatic structures are located in the acinus.

Which normal physiologic change occurs in the aging pulmonary system? a. Decreased flow resistance b. Fewer alveoli c. Stiffening of the chest wall d. Improved elastic recoil

ANS: C Normal alterations include (1) loss of elastic recoil, (2) stiffening of the chest wall, (3) alterations in gas exchange, and (4) increases in flow resistance

Which receptors are located near the respiratory center? a. Peripheral chemoreceptors b. Stretch receptors c. Central chemoreceptors d. J-receptors

ANS: C Of the options available, only the central chemoreceptors are located near the respiratory center.

Surfactant produced by type II alveolar cells facilitates alveolar distention and ventilation by which mechanism? a. Decreasing thoracic compliance b. Attracting water to the alveolar surface c. Decreasing surface tension in the alveoli d. Increasing surface tension in the alveoli

ANS: C Surfactant, a lipoprotein produced by type II alveolar cells, has a detergent-like effect that separates the liquid molecules, thereby decreasing alveolar surface tension.

How low must the partial pressure of arterial oxygen (PaO2) drop before the peripheral chemoreceptors influence ventilation? a. Below 100 mm Hg b. Below 80 mm Hg c. Below 70 mm Hg d. Below 60 mm Hg

ANS: C The PaO2 must drop well below normal (to approximately 60 mm Hg) before the peripheral chemoreceptors have much influence on ventilation.