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Beachey: Respiratory Care Anatomy and Physiology, 3rd Edition Chapter 01: The Airways and AlveoliAnswers to Workbook QuestionsKey Terms and DefinitionsAtelectasis—an area of collapsed or airless alveoli. Edema—swelling caused by fluid collection within the interstitial space.Intubation—the insertion of an endotracheal tube into the trachea.Tracheostomy—a surgical opening in the trachea, generally located 1 to 3 cm below the cricoid cartilage.Bronchospasm—narrowing of the bronchi caused by bronchial smooth muscle constriction.Laryngospasm—laryngeal stimulation resulting in occlusion of the tracheal opening due to closure of the vocal cords.Intrapulmonary shunt—blood that travels through the pulmonary vasculature without participating in gas exchange; it is the most common cause of hypoxemia. Hypoxemia—decreased oxygen content in the blood.Humidity deficit—the difference between the water content of a gas at room temperature and the water content of a gas at body temperature.Ventilator-associated pneumonia (VAP)—new occurrence of pneumonia that develops within 48 hours after mechanical ventilation has been initiated. MatchingDECBJHGAFLabelingNasal cavityNasopharynxOropharynxLaryngopharynxLarynxTracheaLeft and right primary bronchiBronchiolesAlveoliCapillaryAlveolar sacAlveolar ductLower respiratory tractUpper respiratory tract EpiglottisCorniculate cartilageArytenoid cartilageParathyroid glandMembranous part of tracheaTracheaThyroid glandCricoid cartilageThyroid cartilageThyroid ligamentHyoid boneTracheaThyroid gland Cricoid cartilageThyroid cartilageThyrohyoid ligamentHyoid boneTracheal cartilageCricothyroid ligamentSuperior thyroid notch3.Base of tongueVocal foldsArytenoids cartilageCuneiform cartilageCorniculate cartilageTracheaVestibular foldEpiglottisvallecula4.Respiratory or gas exchange zone17–23Cartilage resembling that found in the trachea is located in levels 1–6 (conducting zone).The carina is the point of division for the mainstem bronchi. The external landmark for this division point is the fifth thoracic vertebra. Left5.I. TracheaSternumLeft superior lobeLeft primary bronchusBody of sternumOblique fissureLeft inferior lobeSternum (xiphoid process)Right inferior lobeSeventh ribOblique fissueRight middle lobeHorizontal fissureRight primary bronchusRight superior lobeFirst ribII. Superior lobeMiddle lobeMedial segmentLateral segmentMedial basal (cardiac segment)Anterior basal segmentLateral basal segmentPosterior basal segmentSuperior segmentInferior lobeAnterior segmentPosterior segmentApical segmentIII. Apicoposterior segmentSuperior segmentPosterior basal segmentInferior lobeLateral basal segmentAnterior basal segmentMedial basal (cardiac) segmentInferior lingular segmentSuperior lingular segmentAnterior segmentSuperior lobe6. Smooth muscleAlveolar ductPores of kohnAlveolusAlveolar sacRespiratory bronchiolesTerminal bronchiole7.Goblet cellMucous glandSmooth muscleCapillariesCapillariesAventiaSubmucosaLamina propriaEpitheliumMucous blanketMucosa8.The mucus blanket is formed by secretions from goblet cells and submucosal glands.The mucus blanket is composed of two layers. The upper portion is called the gel layer; the function of this layer is to trap particles. The lower portion is called the sol layer. Cilia lining the airway epithelium propel the mucus blanket toward the mouth with each beat.100 mLDisorders that produce abnormal amounts of thick secretions: ciliary disorders; inadequate humidity; infection; and smoking.Short Answer/Critical Thinking QuestionsVentilation—the process of moving gas into and out of the lungRespiration—the transfer of oxygen and CO2 between air and bloodExternal respiration—the exchange of oxygen and CO2 between air and bloodInternal respiration—the exchange of oxygen and CO2 between blood and body fluids (cells)All of the airways down to the level of, but not including, the respiratory zone. Because no gas exchange occurs at this level, gas is simply transported to and from the gas-exchanging units.The turbinates provide an increased surface area of the nasal cavity allowing inhaled gas to pick up more heat and humidity. The turbulent flow of the gas increases the chance that particles will adhere to the mucus for improved filtration.Heating the gas will increase its capacity to hold water, thereby reducing relative humidity. When room air is inspired, the nasopharynx warms the gas, increasing the water vapor capacity. The gas also picks up moisture from the nasal mucosa, increasing the water vapor content and relative humidity of the gas. Conditions that will cause water to evaporate include low body temperature (<37oC); inhaling cold air (below room temperature); and delivery of dry medical gas that bypasses the upper airway. If an artificial airway is in place and supplemental humidity is not added to the inspired gas, water will evaporate from the mucus to make up for the humidity deficit. This will cause the mucus to become thick, making it more difficult to remove.Loss of normal pharyngeal muscle tone during sleep causes the tongue to fall back and partially occlude the upper airway, increasing airway resistance. Abnormal enlargement of soft tissue can further narrow the airway, causing further obstruction, which leads to periods of apnea. Stridor is caused by the vibration of air flowing through a narrowed upper airway. Edema and swelling due to infection or trauma partially obstruct the upper airway, causing the high-pitched crowing sound. Croup is a viral infection that leads to edema and swelling of the glottis. Epiglottitis is a life-threatening bacterial infection that leads to edema and swelling of the epiglottis. The vocal cords play an important role in the generation of the high pressure needed to produce an effective cough. Their ability to open wider during deep inspiration decreases airway resistance, allowing for a deeper inspiration. Cartilage gives rigidity to the large airways, preventing collapse from external pressure during coughing. Because of the angle of the right bronchus, if the endotracheal tube is placed too deep into the trachea it will be more likely to enter the right bronchus, which will prevent gas flow into the left lung. The tethering retractile forces of elastic parenchymal tissue. They are called bronchioles.About 30–40%. So that most of the inhaled gas can come into contact with the gas-exchanging membrane. An endotracheal tube would decrease dead space because it bypasses the upper airway. The acinus consists of the airways distal to the terminal bronchioles (respiratory bronchioles, alveolar ducts, and alveolus). Pores of Kohn and canals of Lambert are present in the acinus; their function is to provide collateral air passage to nearby alveoli in the event of mucus plugging. All of the upper airways combined, because the lower airways have a greater cross-sectional surface area. Tobacco smoke decreases motility of the cilia and causes the mucus glands to proliferate and spread into small bronchioles.True. Upper airway reflexes along with the mucociliary clearance mechanism and cough work to keep the lower airways free of microorganisms. Bacterial infection. Neutrophils are white blood cells (also called pus cells) that migrate to the airway to rid it of bacteria by phagocytosis. Allergic asthma. Allergic asthma is caused by an IgE-mediated immune response where an inhaled irritant causes an abnormal antigen response and subsequent increase in the production of IgE. IgE binds to specific receptor sites on the mast cell surface sensitizing the mast cell. The antigen combines with IgE molecules on the mast cell surface inactivating the antigen and causing the mast cell to rupture. Rupture of the mast cell releases histamine and other inflammatory mediators that lead to bronchoconstriction, inflammation, and increased mucus production. Secretion of chloride ions is necessary for the osmotic forces that move water into the airway lumen to hydrate mucus and facilitate ciliary function. In cystic fibrosis, there is a defect in chloride ion secretion that leads to thick dehydrated secretions. Beta-adrenergic drugs cause smooth muscle relaxation by stimulating the sympathetic nervous system. Sympathetic stimulation produces watery secretions, which enhance mucociliary clearance.Alveolar airway epithelium contains flat type I cells and polygon-shaped type II cells that provide an alveolar-capillary membrane that is highly permeable to gas but impermeable to liquid solutions. Type II cells produce surfactant, a substance essential for preventing alveolar collapse.Conducting airway epithelium consists of tall, columnar, ciliated, pseudo-stratified epithelial cells interspersed with numerous mucus-secreting cells. These cells are essential for mucociliary clearance. Alveolar macrophages engulf and digest microorganisms and foreign material. Some phagocytized material is dissolved, and some is simply surrounded and isolated. After ingestion of foreign material one of the following may occur: macrophages may migrate into the airways, where ciliary activity removes the particles; they may migrate to the interstitial space and remain there; they may enter the lymphatic system; or they may simply die and remain in the alveolus.Pulmonary interstitium is the space between the alveolar epithelium and capillary endothelium.Tobacco smoke increases phagocytosis and the release of proteases (enzymes) that eventually degrade and destroy cellular protein and elastic tissue, leading to a state of chronic inflammation and alveolar destruction—the primary feature of emphysema. Case StudyYou need to determine the correct placement of the endotracheal tube in the trachea. Intubation of the esophagus rather than the trachea.The left lung most likely has no breath sounds since the left mainstem bronchus has a sharper angle than the right, making it easier for the tube to enter the right mainstem and ventilate the right lung. Pulling back on the endotracheal tube until breath sounds are heard in the both the left and right lung fields will correct the problem. The use of a device to detect CO2 will ensure that the endotracheal tube is in the trachea. A chest x-ray will ensure correct positioning of the endotracheal tube. An artificial airway will prevent upper airway obstruction caused by relaxation of pharyngeal muscles. Ensure the provision of adequate heat and humidity to prevent mucus plugging, which can lead to obstruction and infection. Key Concept QuestionsB. This maneuver pulls the tongue forward and aligns the oral and nasal cavities with the pharynx-larynx axis, allowing easier passage of air into the lungs.C. Mast cell degranulation and airway inflammation are features of asthma; therefore, the use of a drug that inhibits mast cell breakdown would be an effective treatment for asthma.D. Increased permeability of the alveolar-capillary membrane causes fluid to move into the interstitial spaces and eventually into the alveoli.A. Decreased levels of surfactant cause alveoli to collapse and make the lung harder to ventilate, thus requiring increased pressure for delivery of each breath. ................
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