Presentation on theme: "Chapter 23: The Respiratory System"— Presentation transcript:
1Chapter 23: The Respiratory System Copyright 2009, John Wiley & Sons, Inc.
2Respiratory System Anatomy StructurallyUpper respiratory systemNose, pharynx and associated structuresLower respiratory systemLarynx, trachea, bronchi and lungsFunctionallyConducting zone – conducts air to lungsNose, pharynx, larynx, trachea, bronchi, bronchioles and terminal bronchiolesRespiratory zone – main site of gas exchangeRespiratory bronchioles, alveolar ducts, alveolar sacs, and alveoliCopyright 2009, John Wiley & Sons, Inc.
4Copyright 2009, John Wiley & Sons, Inc. NoseExternal nose – portion visible on faceInternal nose – large cavity beyond nasal vestibuleInternal nares or choanaeDucts from paranasal sinuses and nasolacrimal ducts open into internal noseNasal cavity divided by nasal septumNasal conchae subdivide cavity into meatusesIncrease surface are and prevents dehydrationOlfactory receptors in olfactory epitheliumCopyright 2009, John Wiley & Sons, Inc.
7Copyright 2009, John Wiley & Sons, Inc. PharynxStarts at internal nares and extends to cricoid cartilage of larynxContraction of skeletal muscles assists in deglutitionFunctionsPassageway for air and foodResonating chamberHouses tonsils3 anatomical regionsNasopharynxOropharynxLaryngopharynxCopyright 2009, John Wiley & Sons, Inc.
8Copyright 2009, John Wiley & Sons, Inc. LarynxShort passageway connecting laryngopharynx with tracheaComposed of 9 pieces of cartilageThyroid cartilage or Adam’s appleCricoid cartilage hallmark for tracheotomyEpiglottis closes off glottis during swallowingGlottis – pair of folds of mucous membranes, vocal folds (true vocal cords and rima glottidis)Cilia in upper respiratory tract move mucous and trapped particles down toward pharynxCilia in lower respiratory tract move them up toward pharynxCopyright 2009, John Wiley & Sons, Inc.
9Copyright 2009, John Wiley & Sons, Inc. LarynxCopyright 2009, John Wiley & Sons, Inc.
10Structures of Voice Production Mucous membrane of larynx formsVentricular folds (false vocal cords) – superior pairFunction in holding breath against pressure in thoracic cavityVocal folds (true vocal cords) – inferior pairMuscle contraction pulls elastic ligaments which stretch vocal folds out into airwayVibrate and produce sound with airFolds can move apart or together, elongate or shorten, tighter or looserAndrogens make folds thicker and longer – slower vibration and lower pitchCopyright 2009, John Wiley & Sons, Inc.
12Copyright 2009, John Wiley & Sons, Inc. TracheaExtends from larynx to superior border of T5Divides into right and left primary bronchi4 layersMucosaSubmucosaHyaline cartilageAdventitia16-20 C-shaped rings of hyaline cartilageOpen part faces esophagusCopyright 2009, John Wiley & Sons, Inc.
13Copyright 2009, John Wiley & Sons, Inc. Location of TracheaCopyright 2009, John Wiley & Sons, Inc.
14Copyright 2009, John Wiley & Sons, Inc. BronchiSuperior border of 5th thoracic vertebra trachea divides into right and left primary bronchus.Right is more vertical, shorter, and wider – aspiration more likely to affect right sideCarina – site where bronchi divide is an internal ridgeMost sensitive area for triggering cough reflexDivide to form bronchial treeSecondary lobar bronchi (one for each lobe), tertiary (segmental) bronchi, bronchioles, terminal bronchiolesCopyright 2009, John Wiley & Sons, Inc.
15Copyright 2009, John Wiley & Sons, Inc. BronchiStructural changes with branchingMucous membrane changes – ciliated simple columnar with goblet cells in larger bronchioles to ciliated simple cuboidal with no goblet cells in smaller bronchioles to mostly nonciliated simple cuboidal in terminal bronchioles (macrophages take over)Incomplete rings of cartilage become plates and then disappear in distal bronchiolesAs cartilage decreases, smooth muscle increasesSympathetic ANS – relaxation/ dilationParasympathetic ANS and histamine have opposite effect – contraction/ constrictionCopyright 2009, John Wiley & Sons, Inc.
17Copyright 2009, John Wiley & Sons, Inc. LungsSeparated from each other by the heart and other structures in the mediastinumEach lung enclosed by double-layered pleural membraneParietal pleura – lines wall of thoracic cavityVisceral pleura – covers lungs themselvesPleural cavity is space between layersPleural fluid reduces friction, produces surface tension (stick together)Cardiac notch – heart makes left lung 10% smaller than rightCopyright 2009, John Wiley & Sons, Inc.
18Relationship of the Pleural Membranes to Lungs Copyright 2009, John Wiley & Sons, Inc.
19Copyright 2009, John Wiley & Sons, Inc. Anatomy of LungsLobes – each lung divides by 1 or 2 fissuresEach lobe receives it own secondary (lobar) bronchus that branch into tertiary (segmental) bronchiLobules wrapped in elastic connective tissue and contains a lymphatic vessel, arteriole, venule and branch from terminal bronchioleTerminal bronchioles branch into respiratory bronchioles which divide into alveolar ductsAbout 25 orders of branchingCopyright 2009, John Wiley & Sons, Inc.
21Microscopic Anatomy of Lobule of Lungs Copyright 2009, John Wiley & Sons, Inc.
22Copyright 2009, John Wiley & Sons, Inc. AlveoliCup-shaped outpouchingAlveolar sac – 2 or more alveoli sharing a common opening2 types of alveolar epithelial cellsType I alveolar cells – form nearly continuous lining, more numerous than type II, main site of gas exchangeType II alveolar cells – free surfaces contain microvilli, secrete alveolar fluid (surfactant reduces tendency to collapse)Surfactant - a combination of phospholipids and lipoproteins that reduce surface tension preventing alveoli from collapsingCopyright 2009, John Wiley & Sons, Inc.
23Copyright 2009, John Wiley & Sons, Inc. AlveolusRespiratory membraneAlveolar wall – type I and type II alveolar cellsEpithelial basement membraneCapillary basement membraneCapillary endotheliumVery thin – only 0.5 µm thick to allow rapid diffusion of gasesLungs receive blood fromPulmonary artery – “deoxygenated” bloodBronchial arteries – oxygenated blood to perfuse muscular walls of bronchi and bronchiolesCopyright 2009, John Wiley & Sons, Inc.
24Components of Alveolus Copyright 2009, John Wiley & Sons, Inc.
26Pulmonary ventilation Respiration (gas exchange) stepsPulmonary ventilation/ breathingInhalation and exhalationExchange of air between atmosphere and alveoliExternal (pulmonary) respirationExchange of gases between alveoli and bloodInternal (tissue) respirationExchange of gases between systemic capillaries and tissue cellsSupplies cellular respiration (makes ATP)Copyright 2009, John Wiley & Sons, Inc.
27Inhalation/ inspiration Pressure inside alveoli must become lower than atmospheric pressure for air to flow into lungs760 millimeters of mercury (mmHg) or 1 atmosphere (1 atm)Achieved by increasing size of lungsBoyle’s Law – pressure of a gas in a closed container is inversely proportional to the volume of the containerInhalation – lungs must expand, increasing lung volume, decreasing pressure below atmospheric pressureCopyright 2009, John Wiley & Sons, Inc.
28Copyright 2009, John Wiley & Sons, Inc. Boyle’s LawCopyright 2009, John Wiley & Sons, Inc.
29Copyright 2009, John Wiley & Sons, Inc. InhalationInhalation is active – Contraction ofDiaphragm – most important muscle of inhalationFlattens, lowering dome when contractedResponsible for 75% of air entering lungs during normal quiet breathingExternal intercostalsContraction elevates ribs25% of air entering lungs during normal quiet breathingAccessory muscles for deep, forceful inhalationWhen thorax expands, parietal and visceral pleurae adhere tightly due to subatmospheric pressure and surface tension – pulled along with expanding thoraxAs lung volume increases, alveolar (intrapulmonic) pressure dropsCopyright 2009, John Wiley & Sons, Inc.
31Exhalation/ expiration Pressure in lungs greater than atmospheric pressureNormally passive – muscle relax instead of contractBased on elastic recoil of chest wall and lungs from elastic fibers and surface tension of alveolar fluidDiaphragm relaxes and become dome shapedExternal intercostals relax and ribs drop downExhalation only active during forceful breathingCopyright 2009, John Wiley & Sons, Inc.
34Copyright 2009, John Wiley & Sons, Inc. AirflowAir pressure differences drive airflow3 other factors affect rate of airflow and ease of pulmonary ventilationSurface tension of alveolar fluidCauses alveoli to assume smallest possible diameterAccounts for 2/3 of lung elastic recoilPrevents collapse of alveoli at exhalationLung complianceHigh compliance means lungs and chest wall expand easilyRelated to elasticity and surface tensionAirway resistanceLarger diameter airway has less resistanceRegulated by diameter of bronchioles & smooth muscle toneCopyright 2009, John Wiley & Sons, Inc.
35Lung volumes and capacities The minute volume of respiration is the total volume of air taken in during one minutetidal volume x 12 respirations per minute = 6000 ml/minTidal volume is normally 500 mLDoes not account for dead spaceCopyright 2009, John Wiley & Sons, Inc.
36Copyright 2009, John Wiley & Sons, Inc. Lung VolumesOnly about 70% of tidal volume reaches respiratory zoneOther 30% remains in conducting zoneAnatomic (respiratory) dead space – conducting airways with air that does not undergo respiratory gas exchangeAlveolar ventilation rate – volume of air per minute that actually reaches respiratory zoneInspiratory reserve volume – taking a very deep breathCopyright 2009, John Wiley & Sons, Inc.
37Spirogram of Lung Volumes and Capacities Copyright 2009, John Wiley & Sons, Inc.
39LUNG VOLUMES AND CAPACITIES Air volumes exchanged during breathing and rate of ventilation are measured with a spiromometer and the record is called a spirogramAmong the pulmonary air volumes exchanged in ventilation aretidal (500 ml)inspiratory reserve (3100 ml)expiratory reserve (1200 ml)residual (1200 ml)minimal volumes.Only about 350 ml of the tidal volume actually reaches the alveoli, the other 150 ml remains in the airways as anatomic dead spaceCopyright 2009, John Wiley & Sons, Inc.
40LUNG VOLUMES AND CAPACITIES Pulmonary lung capacities, the sum of two or more volumes, includeinspiratory (3600 ml)functional residual (2400 ml)vital (4800 ml)total lung (6000 ml) capacities .Copyright 2009, John Wiley & Sons, Inc.
41Copyright 2009, John Wiley & Sons, Inc. RESPIRATORY VOLUMESTidal volume: During normal breathing about 500mL of air moves into and out of the lungs with each breath.The amount of air that can be inspired forcibly beyond the tidal volume is called inspiratory reserve volume (IRV).Copyright 2009, John Wiley & Sons, Inc.
42Copyright 2009, John Wiley & Sons, Inc. RESPIRATORY VOLUMESExpiratory reserve volume (ERV) is the amount of air that can be evacuated from the lungs after tidal expiration.Even after the most strenuous expiration only about 1200 mL of air remains in the lungs; this is the residual volume which helps to keep the alveoli patent and prevent lung collapse.Copyright 2009, John Wiley & Sons, Inc.
43RESPIRATORY CAPACITIES The inspiratory capacity is the total amount of air that can be inspired after a tidal expiration, so it is the sum of the TV + IRV.Functional residual capacity represents the amount of air remaining in the lungs after a tidal expiration and the combined RV + ERV.Copyright 2009, John Wiley & Sons, Inc.
44RESPIRATORY CAPACITIES Vital capacity is the total amount of exchangeable air. It is the sum of TV + IRV + ERV. In healthy young males VC is approximately 4800 mLTotal Lung Capacity is the sum of all lung volumes and is normally around 6 L.Copyright 2009, John Wiley & Sons, Inc.
45Copyright 2009, John Wiley & Sons, Inc. Dead Spacesome of the inspired air fills the conducting passageways and never contributes to gas exchange.The volume of these conducting zones makes up the anatomic dead space.Anatomic dead space equals a mL / # of ideal body weight.This means that in an normal 500 mL TV, only 350 ml is involved in alveolar ventilation.Copyright 2009, John Wiley & Sons, Inc.
46PULMONARY FUNCTION TESTS For evaluating losses in respiratory function and for following the course of certain respiratory diseases.It cannot provide a specific diagnosis, but it can distinguish between:obstructive pulmonary disease involving increased airway resistance such as emphysemarestrictive pulmonary diseases involving a reduction in total lung capacity resulting from structural or functional changes in the lungs (TB, fibrosis due to occupational exposure).Copyright 2009, John Wiley & Sons, Inc.
47PULMONARY FUNCTION TESTS More information can be obtained about a patient’s ventilation status by assessing the rate at which gas moves into and out of the lungs.the minute ventilation is the total amount of gas that flows into or out of the respiratory tract in 1 minute.During normal quiet breathing the minute ventilation in healthy people is about 6 L/min.During rigorous exercise the minute ventilation may reach 200 L/min.Copyright 2009, John Wiley & Sons, Inc.
48PULMONARY FUNCTION TESTS Two unusual tests are FVC and FEV.FVC, forced vital capacity, measures the amount of gas expelled when a subject takes a deep breath and the forcefully exhales maximally and as rapidly as possible.FEV, forced expiratory volume, determines the amount of air expelled during specific time intervals. The volume exhaled during the first second is the FEV1.Those with healthy lungs can exhale out 80%.Those with obstructive disease exhale considerably less while those with restrictive disease exhales 80% or more even though their FVC is reduced.Copyright 2009, John Wiley & Sons, Inc.
49PULMONARY FUNCTION TESTS Increases in TLC, FRC and RV may occur due to hyperinflation due to obstructive diseases.VC, TLC, FRC, and RV are reduced in restrictive diseases with limit lung expansion.Copyright 2009, John Wiley & Sons, Inc.
51Exchange of Oxygen and Carbon Dioxide Dalton’s LawEach gas in a mixture of gases exerts its own pressure as if no other gases were presentPressure of a specific gas is partial pressure PxTotal pressure is the sum of all the partial pressuresAtmospheric pressure (760 mmHg) = PN2 + PO2 + PH2O + PCO2 + Pother gasesEach gas diffuses across a permeable membrane from the area where its partial pressure is greater to the area where its partial pressure is lessThe greater the difference, the faster the rate of diffusionCopyright 2009, John Wiley & Sons, Inc.
52Partial Pressures of Gases in Inhaled Air PN2=0.786x 760mm Hg= mmHgPO2=0.209= mmHgPH2O=0.004= 3.0 mmHgPCO2=0.0004= 0.3 mmHgPother gases=0.0006= 0.5 mmHgTOTAL= mmHgCopyright 2009, John Wiley & Sons, Inc.
53Copyright 2009, John Wiley & Sons, Inc. Henry’s lawQuantity of a gas that will dissolve in a liquid is proportional to the partial pressures of the gas and its solubilityHigher partial pressure of a gas over a liquid and higher solubility, more of the gas will stay in solutionMuch more CO2 is dissolved in blood than O2 because CO2 is 24 times more solubleEven though the air we breathe is mostly N2, very little dissolves in blood due to low solubilityDecompression sickness (bends)Copyright 2009, John Wiley & Sons, Inc.
54External Respiration in Lungs OxygenOxygen diffuses from alveolar air (PO2 105 mmHg) into blood of pulmonary capillaries (PO2 40 mmHg)Diffusion continues until PO2 of pulmonary capillary blood matches PO2 of alveolar airSmall amount of mixing with blood from conducting portion of respiratory system drops PO2 of blood in pulmonary veins to 100 mmHgCarbon dioxideCarbon dioxide diffuses from deoxygenated blood in pulmonary capillaries (PCO2 45 mmHg) into alveolar air (PCO2 40 mmHg)Continues until of PCO2 blood reaches 40 mmHgCopyright 2009, John Wiley & Sons, Inc.
55Copyright 2009, John Wiley & Sons, Inc. Internal RespirationInternal respiration – in tissues throughout bodyOxygenOxygen diffuses from systemic capillary blood (PO2 100 mmHg) into tissue cells (PO2 40 mmHg) – cells constantly use oxygen to make ATPBlood drops to 40 mmHg by the time blood exits the systemic capillariesCarbon dioxideCarbon dioxide diffuses from tissue cells (PCO2 45 mmHg) into systemic capillaries (PCO2 40 mmHg) – cells constantly make carbon dioxidePCO2 blood reaches 45 mmHgAt rest, only about 25% of the available oxygen is usedDeoxygenated blood would retain 75% of its oxygen capacityCopyright 2009, John Wiley & Sons, Inc.
57Rate of Pulmonary and Systemic Gas Exchange Depends onPartial pressures of gasesAlveolar PO2 must be higher than blood PO2 for diffusion to occur – problem with increasing altitudeSurface area available for gas exchangeDiffusion distanceMolecular weight and solubility of gasesO2 has a lower molecular weight and should diffuse faster than CO2 except for its low solubility - when diffusion is slow, hypoxia occurs before hypercapniaCopyright 2009, John Wiley & Sons, Inc.
58Transport of Oxygen and Carbon Dioxide Oxygen transportOnly about 1.5% dissolved in plasma98.5% bound to hemoglobin in red blood cellsHeme portion of hemoglobin contains 4 iron atoms – each can bind one O2 molecule - OxyhemoglobinOnly dissolved portion can diffuse out of blood into cellsOxygen must be able to bind and dissociate from hemeCopyright 2009, John Wiley & Sons, Inc.
60Relationship between Hemoglobin and Oxygen Partial Pressure Higher the PO2, More O2 combines with HbFully saturated – completely converted to oxyhemoglobinPercent saturation expresses average saturation of hemoglobin with oxygenOxygen-hemoglobin dissociation curveIn pulmonary capillaries, O2 loads onto HbIn tissues, O2 is not held and unloaded75% may still remain in deoxygenated blood (reserve)Copyright 2009, John Wiley & Sons, Inc.
61Oxygen-hemoglobin Dissociation Curve Copyright 2009, John Wiley & Sons, Inc.
62Copyright 2009, John Wiley & Sons, Inc. Hemoglobin and OxygenOther factors affecting affinity of Hemoglobin for oxygenEach makes sense if you keep in mind that metabolically active tissues need O2, and produce acids, CO2, and heat as wastesAcidityPCO2TemperatureCopyright 2009, John Wiley & Sons, Inc.
63Copyright 2009, John Wiley & Sons, Inc. Bohr EffectAs acidity increases (pH decreases), affinity of Hb for O2 decreasesIncreasing acidity enhances unloadingShifts curve to rightPCO2Also shifts curve to rightAs PCO2 rises, Hb unloads oxygen more easilyLow blood pH can result from high PCO2Copyright 2009, John Wiley & Sons, Inc.
64Copyright 2009, John Wiley & Sons, Inc. Temperature ChangesWithin limits, as temperature increases, more oxygen is released from HbDuring hypothermia, more oxygen remains bound2,3-bisphosphoglycerateBPG formed by red blood cells during glycolysisHelps unload oxygen by binding with HbCopyright 2009, John Wiley & Sons, Inc.
65Fetal and Maternal Hemoglobin Fetal hemoglobin has a higher affinity for oxygen than adult hemoglobinHb-F can carry up to 30% more oxygenMaternal blood’s oxygen readily transferred to fetal bloodCopyright 2009, John Wiley & Sons, Inc.
66Carbon Dioxide Transport Dissolved CO2Smallest amount, about 7%Carbamino compoundsAbout 23% combines with amino acids including those in HbCarbaminohemoglobinBicarbonate ions70% transported in plasma as HCO3-Enzyme carbonic anhydrase forms carbonic acid (H2CO3) which dissociates into H+ and HCO3-Copyright 2009, John Wiley & Sons, Inc.
67Copyright 2009, John Wiley & Sons, Inc. CO2 + H2O ↔ H2CO3 ↔ H+ + HCO3-Chloride shiftHCO3- accumulates inside RBCs as they pick up carbon dioxideSome diffuses out into plasmaTo balance the loss of negative ions, chloride (Cl-) moves into RBCs from plasmaReverse happens in lungs – Cl- moves out as moves back into RBCsCopyright 2009, John Wiley & Sons, Inc.
69CONTROL OF RESPIRATION The area of the brain from which nerve impulses are sent to respiratory muscles is located bilaterally in the reticular formation of the brain stem.This respiratory center consists of a medullary rhythmicity area (inspiratory and expiratory areas), pneumotaxic area, and apneustic area (Figure 23.24).Copyright 2009, John Wiley & Sons, Inc.
71Medullary Rhythmicity Area The function of the medullary rhythmicity area is to control the basic rhythm of respiration.The inspiratory area has an intrinsic excitability of autorhythmic neurons that sets the basic rhythm of respiration.The expiratory area neurons remain inactive during most quiet respiration but are probably activated during high levels of ventilation to cause contraction of muscles used in forced (labored) expiration (Figure 23.25).Copyright 2009, John Wiley & Sons, Inc.
72Copyright 2009, John Wiley & Sons, Inc. Pneumotaxic AreaThe pneumotaxic area in the upper pons helps coordinate the transition between inspiration and expiration (Figure 23.25).The apneustic area sends impulses to the inspiratory area that activate it and prolong inspiration, inhibiting expiration.Copyright 2009, John Wiley & Sons, Inc.
74Regulation of the Respiratory Center Cortical influences allow conscious control of respiration that may be needed to avoid inhaling noxious gasses or water.Breath holding is limited by the overriding stimuli of increased [H+] and [CO2].Copyright 2009, John Wiley & Sons, Inc.
75Chemoreceptor Regulation of Respiration Central chemoreceptors (located in the medulla oblongata) and peripheral chemoreceptors (located in the walls of systemic arteries) monitor levels of CO2 and O2 and provide input to the respiratory center (Figure 23.26).Central chemoreceptors respond to change in H+ concentration or PCO2, or both in cerebrospinal fluid.Peripheral chemoreceptors respond to changes in H+, PCO2, and PO2 in blood.A slight increase in PCO2 (and thus H+), a condition called hypercapnia, stimulates central chemoreceptors (Figure 23.27).Copyright 2009, John Wiley & Sons, Inc.
77Copyright 2009, John Wiley & Sons, Inc. Central chemoreceptors respond to changes in H+ concentration or PCO2, or both in cerebrospinal fluid.Peripheral chemoreceptors respond to changes in H+, PCO2, and PO2 in blood.A slight increase in PCO2 (and thus H+), a condition called hypercapnia, stimulates central chemoreceptors (Figure 23.27).Copyright 2009, John Wiley & Sons, Inc.
79Copyright 2009, John Wiley & Sons, Inc. As a response to increased PCO2, increased H+ and decreased PO2, the inspiratory area is activated and hyperventilation, rapid and deep breathing, occursIf arterial PCO2 is lower than 40 mm Hg, a condition called hypocapnia, the chemoreceptors are not stimulated and the inspiratory area sets its own pace until CO2 accumulates and PCO2 rises to 40 mm Hg.Copyright 2009, John Wiley & Sons, Inc.
80Copyright 2009, John Wiley & Sons, Inc. Severe deficiency of O2 depresses activity of the central chemoreceptors and respiratory center.Hypoxia refers to oxygen deficiency at the tissue level and is classified in several waysHypoxic hypoxia is caused by a low PO2 in arterial blood (high altitude, airway obstruction, fluid in lungs).Copyright 2009, John Wiley & Sons, Inc.
81Copyright 2009, John Wiley & Sons, Inc. In anemic hypoxia, there is too little functioning hemoglobin in the blood (hemorrhage, anemia, carbon monoxide poisoning).Stagnant hypoxia results from the inability of blood to carry oxygen to tissues fast enough to sustain their needs (heart failure, circulatory shock).In histotoxic hypoxia, the blood delivers adequate oxygen to the tissues, but the tissues are unable to use it properly (cyanide poisoning).Copyright 2009, John Wiley & Sons, Inc.
82Copyright 2009, John Wiley & Sons, Inc. Proprioceptors of joints and muscles activate the inspiratory center to increase ventilation prior to exercise induced oxygen need.The inflation (Hering-Breuer) reflex detects lung expansion with stretch receptors and limits it depending on ventilatory need and prevention of damage.Other influences include blood pressure, limbic system, temperature, pain, stretching the anal sphincter, and irritation to the respiratory mucosaCopyright 2009, John Wiley & Sons, Inc.
84DISORDERS: HOMEOSTATIC IMBALANCES Asthma is characterized by the following: spasms of smooth muscle in bronchial tubes that result in partial or complete closure of air passageways; inflammation; inflated alveoli; and excess mucus production. A common triggering factor is allergy, but other factors include emotional upset, aspirin, exercise, and breathing cold air or cigarette smoke.Chronic obstructive pulmonary disease (COPD) is a type of respiratory disorder characterized by chronic and recurrent obstruction of air flow, which increases airway resistance. The principal types of COPD are emphysema and chronic bronchitis.Copyright 2009, John Wiley & Sons, Inc.
85DISORDERS: HOMEOSTATIC IMBALANCES Pneumonia is an acute infection of the alveoli. The most common cause in the pneumococcal bacteria but other microbes may be involved. Treatment involves antibiotics, bronchodilators, oxygen therapy, and chest physiotherapy.Tuberculosis (TB) is an inflammation of pleurae and lungs produced by the organism Mycobacterium tuberculosis. It is communicable and destroys lung tissue, leaving nonfunctional fibrous tissue behind.Copyright 2009, John Wiley & Sons, Inc.
86DISORDERS: HOMEOSTATIC IMBALANCES Cystic fibrosis is an inherited disease of secretory epithelia that affects the respiratory passageways, pancreas, salivary glands, and sweat glands.Sudden Infant Death Syndrome is the sudden death of an apparently healthy infant, usually occurring during sleep. The cause is unknown but may be associated with hypoxia, possibly resulting from sleeping position. As such, it is recommended that infants sleep on their backs for the first six months.Copyright 2009, John Wiley & Sons, Inc.
87Copyright 2009, John Wiley & Sons, Inc. End of Chapter 23Copyright 2009 John Wiley & Sons, Inc. All rights reserved. Reproduction or translation of this work beyond that permitted in section 117 of the 1976 United States Copyright Act without express permission of the copyright owner is unlawful. Request for further information should be addressed to the Permission Department, John Wiley & Sons, Inc. The purchaser may make back-up copies for his/her own use only and not for distribution or resale. The Publishers assumes no responsibility for errors, omissions, or damages caused by the use of theses programs or from the use of the information herein.Copyright 2009, John Wiley & Sons, Inc.