Chapter 08: The Respiratory System Test Bank

Limited, short-term spontaneous ventilation is possible in a patient with a paralyzed diaphragm. a. True b. False c. unable to determine

ANS: A Although the diaphragm is the primary ventilatory muscle, it is not essential for survival. Limited, short-term ventilation is possible using accessory muscles, even if the diaphragm is paralyzed. The diaphragm does not actively participate in exhalation. During exhalation, it returns to its resting position during the passive recoil of the lungs and thorax. During forced exhalation, abdominal wall muscles compress the abdominal cavity and increase pressure in the abdominal cavity. This forces the diaphragm upward and compresses the lungs and forces gas from them. The diaphragm performs important functions other than ventilation. It aids in generating high intra-abdominal pressures by remaining fixed while the abdominal muscles contract. This facilitates vomiting, coughing, sneezing, defecation, and parturition.

At what point does the trachea branch into two mainstem bronchi? a. carina b. cricoid cartilage c. glottis d. manubrium

ANS: A At the base of the trachea, the last cartilaginous ring that forms the bifurcation for the two bronchi is called the carina. The carina is an important landmark that is used to identify the level at which the two mainstem bronchi branch off from the trachea.

Which of the following have been shown to injure the alveolar-capillary membrane? 1. excessive pressures 2. excessive tidal volumes 3. increased intracranial pressures 4. pulmonary hypertension a. 1, 2, and 4 b. 2 and 3 c. 4 only d. 1, 2, 3, and 4

ANS: A Conditions of pulmonary hypertension (e.g., capillary pressure greater than 30 mm Hg during congestive heart failure and high-altitude pulmonary edema) and excessive tidal volume and airway pressure during positive-pressure ventilation (e.g., tidal volume greater than 6 ml/kg and airway pressures greater than 30 cm H2O) can result in stress failure of the blood-gas membrane. Stress failure results in endothelial and/or type I cell stretching and shearing injuries.

Which of the following help comprise the defense system of the nose? 1. clearance of foreign matter by ciliary action 2. gross filtration by the large hairs of the nasal vestibule 3. impaction of particulate foreign matter on the nasal mucosa 4. laminar flow through the concha a. 1, 2, and 3 b. 2 and 4 c. 3 only d. 1, 2, 3, and 4

ANS: A Filtration of inhaled air is carried out by the hair in the anterior portion of the cavity and the sticky mucous membrane that covers the complex surface of the cavity. Filtration is enhanced by the flow pattern through the nasal cavity. Inspired gas is accelerated to a high velocity through the anterior nares. It then changes direction sharply as it enters the internal nasal cavity. This pattern causes particles larger than 10 m in diameter to impact on the nasal mucosa. Ciliary action or nose blowing then clears these particles. Past the external nares, the cross-sectional area increases. This results in a decrease in gas velocity. Turbulence increases because of the narrow convolutions of the passages. Low velocity and turbulence combine to remove any remaining particles.

Compared to a normal diaphragm, contraction of a diaphragm that is low and flat may result in which of the following? a. compression of the thoracic cavity b. enhanced venous return and thus cardiac output c. greater diaphragmatic efficiency d. larger than normal change in thoracic volume

ANS: A Increased lung volume causes the diaphragm to flatten out. Contraction of a flattened diaphragm can result in tension on the lower ribs that causes them to be pulled inward, which results in compression of the thoracic cavity. This condition can occur in individuals with severe gas trapping as a result of emphysema or asthma. To compensate for this, these individuals must recruit other muscles to enlarge the thorax. This results in less efficient breathing and excessive muscle work.

What is the major source of respiratory tract secretions in the normal lung? a. bronchial glands b. Clara cells c. goblet cells d. mast cells

ANS: A Normally, the respiratory tract produces about 100 ml of mucus per day. Most of the mucus formed in the larger airways is produced by the bronchial glands.

What is your primary concern if you discover that a patient does not have a gag reflex? a. fear of aspiration of bacteria or food b. that their tonsilar tissues are grossly swollen c. that they will not be able to breathe adequately d. tracheal collapse

ANS: A Reflexes of the mouth, pharynx, and larynx help to protect the lower respiratory tract during swallowing. These protective functions can be severely compromised during anesthesia or unconsciousness. Loss or compromise of these important reflexes can result in aspiration of bacteria colonized saliva or food and can cause pulmonary infection and asphyxiation in severe cases.

How does the body compensate for a pulmonary embolus that occludes a branch of the pulmonary artery? a. increased bronchial arterial flow to the area b. increased cardiac output c. pulmonary arteriole and metarteriole vasodilation d. release of prostaglandins to fight inflammation

ANS: A The bronchial and pulmonary circulations share an important compensatory relationship. Decreased pulmonary arterial blood pressure tends to cause an increase in bronchial artery blood flow to the affected area. This minimizes the danger of pulmonary infarction, as sometimes occurs when a blood clot (pulmonary embolus) enters the lung.

During which phase of fetal development do mature alveoli appear? a. alveolar b. canalicular c. pseudoglandular d. saccular

ANS: A The development of mature alveoli, accompanied by capillary proliferation within the walls, marks the final phase of lung development and is known as the alveolar period.

Which accessory muscles are active during resting and active inspiration and pull up on all the ribs expanding the thorax? a. external intercostals b. internal intercostals c. scalenes d. sternocleidomastoids

ANS: A The external intercostals (Figure 8-22) originate on the upper ribs and attach to the lower ribs. The fibers of these muscles run at an oblique angle between the ribs. When they generate tension, they lift the ribs upward and cause the thoracic cavity to enlarge the thorax.

Changes in the tension on the vocal cords, allowing phonation, are produced by the interaction of the laryngeal muscles and the movement of which cartilage? a. arytenoids b. corniculates c. cricoid d. cuneiforms

ANS: A The laryngeal component of speech is called phonation. It requires the adjustment of vocal cord tension and position relative to one another. The action of the posterior cricoarytenoid muscles causes the arytenoid cartilages to rotate and opens the vocal cords. Closure of the vocal cords is carried out by rotating the arytenoids in the opposite direction through the action of the lateral cricoarytenoid and oblique arytenoid muscles.

What is the most common cell type found in the mucosa of the larger airways? a. pseudostratified ciliated columnar epithelium b. pseudostratified ciliated cuboidal epithelium c. stratified ciliated squamous epithelium d. stratified unciliated serous endothelium

ANS: A The most common type of epithelia is the numerous pseudostratified, ciliated, columnar epithelia.

What strong stimulus to the infant provides the impetus for the first breath? a. acidosis b. exposure to warmth c. fright from passing through the birth canal d. high PaO2

ANS: A The newborn infant is stimulated by new tactile and thermal stimuli, all of which stimulate breathing. In addition, as placental gas transfer is suddenly interrupted, the newborn quickly becomes hypoxemic, hypercapnic, and acidotic.

What is unique regarding the blood supply to the lung? a. It receives blood from right and left ventricles. b. It requires no dedicated blood supply as it exists in a gas environment. c. Pulmonary venous drainage contributes to the normal anatomic shunt. d. The pulmonary arteries are the primary source of oxygen for lung structures.

ANS: A The respiratory system is a unique organ in that it receives a double blood supply: one from the left ventricle and one from the right ventricle.

What is the primary purpose of the respiratory system? a. continuous absorption of oxygen and excretion of carbon dioxide b. filtering to prevent allergens and microbes from reaching the lungs c. transport oxygenated blood to the tissues d. warm and humidify inspired gas

ANS: A The respiratory system's primary function is the continuous absorption of oxygen and the excretion of carbon dioxide.

What is the name of the external landmark that identifies the point at which the trachea branches into the right and left mainstem bronchi? a. angle of Louis b. cricoid cartilage c. suprasternal notch d. xiphoid process

ANS: A The sternal angle is an external marker of the point where the trachea divides into the left and right mainstem bronchi.

As ventilatory muscles, the sternocleidomastoids do which of the following? a. They elevate the upper chest, increasing chest anteroposterior diameter. b. They levate the ribs and decrease chest anteroposterior diameter. c. They increase lateral chest movement during inspiration. d. They llower the sternum, thus increasing chest anteroposterior diameter.

ANS: A The sternocleidomastoid muscles can function to lift the upper chest. They receive nerve impulses from branches of the accessory nerves (cranial nerve XI) and cervical nerves C1 and C2. These muscles are active during forceful inspiration and become visible as thick bands on either side of the neck during the inspiratory phase in an individual who is in respiratory distress. This motion increases the anteroposterior diameter of the chest.

How far is the diaphragm pulled down during tidal breathing? a. 1 to 2 cm b. 3 to 5 cm c. 6 to 8 cm d. 8 to 10 cm

ANS: A When the muscle fibers of the diaphragm are tensioned during inspiration, the dome of the diaphragm is pulled down 1 to 2 cm.

Which phospholipid ratio would indicate a neonate with a low risk of developing respiratory distress syndrome (RDS)? a. L/S ratio of 1 b. L/S ratio of 2 or more c. L/S ratio of less than 1.5 d. L/S ratio of less then 1

ANS: B An L/S ratio of 2 or more indicates a relatively low risk for the development of respiratory distress syndrome, while an L/S ratio of less than 1.5 is associated with a high risk.

The diaphragm is innervated by which of the following nerves? a. glossopharyngeal b. phrenic c. seventh cranial d. vagus

ANS: B Functionally, the diaphragm is divided into a right and left hemidiaphragm. Each hemidiaphragm is innervated by a phrenic nerve that arises from branches of spinal nerves C3, C4, and C5.

Into what structure do the eustachian tubes drain? a. larynx b. nasopharynx c. oropharynx d. vestibule

ANS: B In the lateral nasopharynx, there are two openings into the left and right eustachian tubes that link the upper airway with the middle ear (Figure 8-36). The eustachian tubes drain fluid out of the middle ear and allows gas to move in or out of the middle to equalize pressure on either side of the tympanic membrane.

What pulmonary disorder could lead to acute flattening of the diaphragm? a. adult respiratory distress syndrome b. asthma c. atelectasis d. aneumonia

ANS: B Increased lung volume causes the diaphragm to flatten out. This condition can occur in individuals with severe gas trapping as a result of emphysema or asthma.

The intercostal arteries, veins, and nerves run through which of the following? a. costal groove on the top of each rib b. costal groove on the bottom of each rib c. fibers of the intercostal musculature d. surface of the parietal pleura

ANS: B Just below each rib are a thoracic artery, vein, and nerve that supply blood flow and nerve communications to that region of the chest wall

Identify functions of airway mucus in the normal lung. 1. increased mucus production decreases bronchospasm 2. protect the airways from excessive water loss 3. shield the airway from toxic particles 4. trap inhaled contaminants a. 1, 2, and 3 b. 2, 3, and 4 c. 1 and IV4 d. 3, and 4

ANS: B Mucus functions to protect the underlying tissue. It helps to prevent excessive amounts of water from moving into and out of the epithelia. It shields the epithelia from direct contact with potentially toxic materials and microorganisms. It acts like sticky flypaper to trap particles that make contact with it. This makes mucus an important part of the pulmonary defenses.

Which of the following is an index commonly used to determine relative lung maturity? a. FRC/TLC ratio b. L:S ratio c. RQ ratio d. SP-A

ANS: B Quantification of these phospholipids (the L:S ratio and PG concentration) provides a predictive index of the lung maturity in the fetus before birth and the risks of developing respiratory disease.

Which of rib pairs connect directly to the sternum? a. 1 through 4 b. 1 through 7 c. 1 through 12 d. 11 through 12

ANS: B Rib pairs 1 through 7 are known as the true ribs because they are attached directly to the sternum.

Which of the following statements about the terminal bronchioles is true? a. They are generally five divisions below the segmental bronchi. b. They are the smallest of the purely conducting airways. c. They average 3 to 4 mm in diameter. d. They have well-defined and predictable amounts of cartilage.

ANS: B Terminal bronchioles are the smallest conducting airways and function to supply gas to the respiratory zone of the lung.

Which of the following muscles are considered primary muscles of ventilation? 1. diaphragm 2. intercostals 3. scalenes 4. Sternomastoid a. 1, 3, and 4 b. 1 and 2 c. 3 only d. 1, 2, 3, and 4

ANS: B The diaphragm and intercostal muscles are the primary muscles of ventilation.

What is the space that separates the true vocal cords? a. epiglottis b. glottis c. vallecula d. vestibule

ANS: B The opening formed between the vocal cords is called the glottis

Why is the left lung narrower than the right lung? a. Liver compresses the left lung. b. Mediastinal organs push laterally into the left hemithorax. c. There is poorer blood flow during fetal development. d. There is upward pressure of the abdominal contents.

ANS: B The organs within the mediastinum bulge into the left hemithorax, resulting in a narrower and slightly smaller left lung.

What is the name of the upper portion of the sternum? a. angle of Louis b. manubrium c. vertebral process d. xiphoid process

ANS: B The sternum is a long, vertical flat bone found on the anterior side (Figure 8-18). It is comprised of three bones including the manubrium which comprises the upper portion

What is the name given to the action produced by the forward stroking of millions of cilia? a. coughing b. mucociliary escalator c. mucus stroking d. the wave

ANS: B The stroking action of millions of cilia propels the surrounding mucus at a speed of about 2 cm per minute. This action is commonly referred to as the mucociliary escalator.

Which of the following statements is NOT true regarding the pulmonary circulation? a. Pulmonary blood flow is highly dependent on gravity. b. The pulmonary circulation is a low-pressure system. c. Toward the top of the upright lung, blood flow is high. d. Toward the top of the upright lung, blood flow is low.

ANS: C As a consequence of having a low blood pressure and being susceptible to gravity, blood flow is much higher in the lung bases in resting upright subjects. Gravity-related effects also occur in recumbent positions but are less pronounced.

Which of the following can impair or inhibit ciliary activity? 1. drying of the respiratory tract mucosa 2. exposure to smoke 3. parasympatholytic drugs a. 1 and 2 b. 1 only c. 1, 2, and 3 d. 2 and 3

ANS: C Ciliary beating can be effectively slowed or even stopped if the viscosity of the sol layer is increased by exposure to dry gas. Ciliary motion is also stopped following exposure to smoke, high concentrations of inhaled oxygen, and drugs like atropine.

What results in partial or total obstruction of the airway in an unconscious patient? a. closed mouth coexistent with nasal congestion b. epiglottis relaxes and occludes the laryngeal opening c. relaxation of tongue and hypopharyngeal muscles. d. the uvula occluding the airway

ANS: C During unconsciousness, the muscles of the tongue and hypopharynx can relax and allow the tongue and other soft tissues to collapse and occlude the opening of the hypopharynx. This condition can result in partial to complete blockage of the upper airway and limit air movement to and from the respiratory tract. This is a primary cause of obstructive sleep apnea.

What is a primary function of the larynx? a. cover the glottic opening during forced expiration b. house Waldeyer's ring of tonsilar material for airway defense c. protect airway during eating or drinking d. provide a common passageway for food and gas

ANS: C Generally, it functions to protect the respiratory tract during eating and drinking and in phonation.

What is the only complete circular cartilage of the larynx? a. arytenoid b. corniculate c. cricoid d. Thyroid

ANS: C Just below the thyroid cartilage is the cricoid cartilage, which is the only laryngeal structure that forms a complete ring of cartilage around the airway and is the narrowest region of the upper airway in infants.

What is the name of the negative feedback reflex associated with the termination of inspiration? a. carotid sinus b. Head's paradoxical c. Hering-Breuer d. vagovagal

ANS: C Pulmonary stretch receptors progressively discharge during lung inflation and are linked to inhibition of further inflation. This is a type of negative feedback known as the inflation reflex or the Hering-Breuer inflation reflex

What are rib pairs 11 and 12 known as? a. false ribs b. faux ribs c. floating ribs d. true ribs

ANS: C Rib pairs 11 and 12 are called floating ribs because they are not attached to the sternum.

What intercommunicating channels permit collateral ventilation between adjacent alveoli and primary lobules? 1. bronchial anastomoses 2. canals of Lambert 3. pores of Kohn 4. terminal bronchioles a. 1, 2, and 3 b. 1 and 4 c. 2 and 3 d. 1, 2, 3, and 4

ANS: C Small openings are located in the alveolar septa. Some of the openings allow gas to move from one alveolus to another. These are called the pores of Kohn. Other openings connect alveoli with secondary respiratory bronchioles. These passageways are called the canals of Lambert. All of these alveolar openings and passageways facilitate the collateral movement of gas and help maintain alveolar volume.

What type of alveolar cells cover over 90% of the surface area of the alveolar-capillary membrane? a. alveolar macrophages b. granular pneumocytes c. type I cells d. type II cells

ANS: C The alveolar septa are covered with extremely flat squamous epithelia called type I pneumocytes (Figure 8-54). While they represent only about 8% of all the cells found in the alveolar region, the type I cells cover about 93% of the alveolar surface.

What is the name of the thin serous membrane that covers the inner layer of the thoracic wall? a. cupula b. mesothelioma c. parietal pleura d. visceral pleura

ANS: C The inner layer of the thoracic wall is lined with a serous membrane called the parietal pleura.

Running vertically down each hemithorax anteriorly is an imaginary line that is used as an anatomical landmark. What is that line called? a. anterior axillary line b. midaxillary line c. midclavicular line d. midsternal line

ANS: C The left and right midclavicular lines are parallel to the midsternal line. These are drawn through the midpoints of the left and right clavicles, respectively

Which of the following is NOT a primary function of the nasal cavity? a. conduction of gases b. filtration and defense c. gas exchange d. heat and humidify

ANS: C The primary functions of the nasal cavity are to serve as a gas passageway, and to filter, humidifier, and heat inhaled gases.

What is the function of the thorax? a. facilitate digestion b. heat, humidify, and filter gases c. protect the vital organs d. vocalization

ANS: C The thorax is a cone-shaped cavity that houses the lungs and the contents of the mediastinum (Figure 8-16). It functions to protect the vital organs within and has the capability of changing shape to enable air to be moved into and out of the lungs.

Which of the following is the most important ventilatory function of the scalene muscles? a. Activate if intrathoracic pressure falls to -40 cm H2O. b. Elevate and fix the first seven ribs. c. Lift upper chest particularly during times of high ventilatory demand. d. Support the trachea within the thorax during heavy exercise.

ANS: C Three pairs of scalene muscles (scalenus anterior, scalenus medius, and scalenus posterior) arise from the lower five or six cervical vertebrae and insert on the clavicle and first two ribs (Figure 8-23). They lift the upper chest when active.

Pulmonary surfactant is secreted by which type of lung cells? a. alveolar macrophages b. type I cells (pneumocytes) c. type II pneumocytes d. type III pneumocytes

ANS: C Type II cells do not function as gas exchange membranes like the type I cells. They manufacture surfactant, store it in vesicles called lamellated bodies, and secrete it onto the alveolar surface.

Which of the muscles below when stimulated will contract and push up on the diaphragm? 1. external intercostals 2. external obliques 3. internal obliques 4. rectus abdominous a. 1, 2, and 3 b. 1 and 4 c. 2, 3, and 4 d. 1, 2, 3, and 4

ANS: C When the abdominal wall muscles contract, they compress the abdominal cavity. This forces the diaphragm upward and compresses the thoracic cavity. The abdominal muscles include pairs of external oblique, internal oblique, transverse abdominis, and rectus abdominous muscles (Figure 8-27).

Approximately what percent of the normal changes in thoracic volume during quiet inspiration is due to the action of the diaphragm? a. 15 b. 25 c. 50 d. 75

ANS: D During quiet breathing, the diaphragm is responsible for approximately 75% of the change in thoracic volume.

Which of the following statements describes a normal adult lung? a. The left lung is bisected by two fissures. b. The left lung has an upper, a middle, and a lower lobe. c. The right lung has only an upper and a lower lobe. d. The right lung has three lobes and two fissures.

ANS: D Each lung is divided into two or three lobes (Figure 8-28), which are separated by one or more fissures. The right lung has upper, middle, and lower lobes. The left lung has only an upper and a lower lobe. Both lungs have an oblique fissure that begins on the anterior chest at approximately the sixth rib at the midclavicular line. These fissures extend laterally and upward until they cross the fifth rib on the lateral chest in the midaxillary line. The fissures continue on the posterior chest to approximately the third thoracic vertebra. The right lung also has a horizontal or "minor" fissure that separates the upper and middle lobes.

The nerves that innervate the diaphragm arise from which area? a. lumbar region of the spine b. sacral vertebrae 4 and 5 c. spinal plexuses at T2 to T11 d. spinal nerves C3 to C5

ANS: D Functionally, the diaphragm is divided into a right and left hemidiaphragm. Each hemidiaphragm is innervated by a phrenic nerve that arises from branches of spinal nerves C3, C4, and C5

What factor contributes to increased likelihood of an upper airway obstruction in an infant compared to an adult? a. higher percentage of body fat b. higher volumes of sinus discharge c. relatively smaller head size d. tongue that is proportionally larger

ANS: D Infant neck flexion causes acute airway obstruction. Although the head is larger, an infant's nasal passages are proportionately smaller than are an adult's. In addition, the infant's jaw is much rounder and the tongue is much larger relative to the size of the oral cavity. These anatomic differences increase the likelihood of airway obstruction when an infant becomes unconscious and loses muscle tone.

If premature delivery is anticipated, all of the following will help determine lung maturity, except: a. the presence of oligohydramnios b. ecithin-sphingomyelin (L:S) ratio c. phosphatidylglycerol (PG) concentration d. body mass index (BMI)

ANS: D Quantification of these phospholipids (the L/S ratio and PG concentration) provides a predictive index of the lung maturity in the fetus before birth and the risks of the development of respiratory distress.14 For example, an L/S ratio of 2 or more indicates a relatively low risk for the development of respiratory distress syndrome while an L/S ratio of less than 1.5 is associated with a high risk. Conditions that lead to reduced fetal breathing and amniotic fluid formation (oligohydramnios) are linked to incomplete inflation of the lung with fluid and poorly developed (hypoplastic) lungs.

Why is pulmonary surfactant such an important biologic substance? a. It clears out cellular debris. b. It is an alveolar macrophage. c. It promotes lung contraction aiding exhalation. d. It promotes lung stability.

ANS: D Surfactant functions to reduce the surface tension of the alveolus, which results in shedding water from the alveolar surface; helps to prevent alveolar surface tensiondriven collapse; improves lung compliance; and reduces the work of breathing.

Approximately how many alveoli are there in a 10-year-old's lung? a. 50 million b. 200 million c. 350 million d. 500 million

ANS: D The human lung continues to develop alveoli for years until it reaches a stable stage where the total number have increased to about 480 million alveoli. All of the development is complete by 10 years of age. (he says 300 million)

What is the mediastinum? a. membranous sac surrounding the heart and great vessels b. middle layer of muscle fibers constituting the heart c. point of division of the trachea into the bronchi d. structure separating the right and left thoracic cavities

ANS: D The mediastinum lies between the left and right pleural cavities that contain the lungs (Figure 8-16).

To what structures do the parietal pleural membranes adhere or cover? a. fissures b. intrapulmonary bronchi c. lung d. mediastinum

ANS: D The parietal pleural membrane lines the chest wall and mediastinum, while the lungs are covered by the visceral pleura.

Why do most aspirated objects and fluids end up in the right mainstem bronchus instead of the left mainstem bronchus? a. The left bronchus is more in line with the trachea. b. The left bronchus is shorter than the right. c. The right bronchus is larger than the left. d. The right bronchus is more in line with the trachea.

ANS: D The right bronchus branches off from the trachea at an angle of about 20 to 30 degrees, and the left bronchus branches with an angle of about 45 to 55 degrees (Figure 8-44). The right bronchus's lower angle of branching results in a greater frequency of foreign body passage into the right lung because of the more direct pathway.

What is the cartilage that is commonly referred to as the Adam's apple? a. arytenoid b. cricoid c. cuneiform d. thyroid

ANS: D The thyroid cartilage forms most of the upper portion of the larynx and is generally referred to as the Adam's apple.

By what mechanism does gas exchange across the lung occur? a. active transport b. facilitated diffusion c. facilitated transport d. simple diffusion

ANS: D This close "match" of gas and blood across a large but extremely thin blood-gas barrier membrane enables efficient gas exchange to occur by simple diffusion.

What is meant by "internal respiration"? a. any gas exchange that occurs inside the body b. consumption of oxygen in the mitochondria c. continuous absorption of oxygen and excretion of carbon dioxide d. exchange of gases between the blood and the tissue

ANS: D This process supports internal respiration, which is the exchange of gases between blood and tissues.

What is the primary mechanism that stops the lungs from collapsing at the end of exhalation? a. Radial tethers, stretched to their maximum length, then halt lung collapse. b. Surfactant neutralizes the tendency of the lung to collapse. c. There is a tendency of the chest wall to lock at the level of FRC. d. There is an equal opposing tendency of the chest wall to expand.

ANS: D This tendency of the lung to collapse is counteracted by the thoracic wall's tendency to spring outward and to hold the lung inflated.

What may happen if the irritant receptors in the lung are stimulated? 1. bronchoconstriction 2. reflex closure of the glottis 3. reflex slowing of the heart (bradycardia) a. 2 and 3 b. 1 and 3 c. 2 only d. 1, 2, and 3

ANS: D When the irritant receptors are stimulated, it can result in bronchoconstriction, hyperpnea, glottic closure, cough, and sneeze. Stimulation of these receptors can also cause a reflex slowing of the heart rate (bradycardia).

What maintains lung inflation during fetal development? a. fetal lung fluid b. radial tethering c. rigidity of the chest wall d. surfactant

ANS: A Fetal lung fluid is constantly produced and keeps the fetal lung inflated at a slight positive pressure with respect to amniotic fluid pressure and is important in promoting normal lung development.

What are the free-wandering phagocytic cells that ingest foreign material in the respiratory zone of the lungs? a. alveolar macrophages b. granular pneumocytes c. type I cells d. type II cells

ANS: A Macrophages are another common cell found in the alveolar region. They can move from the pulmonary capillary circulation by squeezing through openings in the alveolar septa and then move out onto the alveolar surface. They are defensive cells that patrol the alveolar region and phagocytize foreign particles and cells (e.g., bacteria).

What is the lowest level on the spinal cord that an injury could cause diaphragmatic impairment or paralysis? a. C3 b. L2 c. S5 d. T4

ANS: A Spinal cord injuries at or above the level of the third cervical vertebrae result in diaphragmatic paralysis.

What is the common name given to classify the airway from the nares to the terminal bronchioles? a. conducting airways b. respiratory airways c. transitional airways d. upper airway

ANS: A The airways from the nares to and including the terminal bronchioles comprise the conducting zone airways, which do not participate in gas exchange.

What position is used to open the airway in an unconscious patient? a. neck extension b. neck flexion c. recovery position d. sniff position

ANS: D With loss of consciousness, the head flexes forward, which can partially or completely obstruct the upper airway. (Figure 8-41, A). Extension of the head and lower jaw into the "sniff" position alleviates this obstruction (Figure 8-41, C). Extension of the head moves the tongue away from the rear of the pharynx. This technique is used to maintain the airway in unconscious patients and facilitates placement of artificial airways.