PowerPoint PresentationRespiratory System FunctionsRespiratory System Bulk FlowFigure 17.1Respiratory System ComponentsFigure 17.2b ANATOMY SUMMARY – The Lungs and Thoracic CavityFigure 17.2a ANATOMY SUMMARY – The Lungs and Thoracic CavityFigure 17.4Conditioning AirFigure 17.5a-b (1 of 8)Figure 17.2f ANATOMY SUMMARY – The Lungs and Thoracic CavityFigure 17.2g ANATOMY SUMMARY – The Lungs and Thoracic CavityFigure 17.2h ANATOMY SUMMARY – The Lungs and Thoracic CavityPulmonary Circulation – high flow, low pressure systemFigure 17.14a (2 of 5)Figure 17.14b (3 of 5)Figure 17.14c (4 of 5)Slide 18Figure 17.8a (3 of 5)Figure 17.8b (4 of 5)Figure 17.8-1 (1 of 5)Figure 17.8-2 (2 of 5)Figure 17.8c (5 of 5)Figure 17.9Figure 17.10a (1 of 2)Figure 17.10b (2 of 2)Compliance and ElastanceFigure 17.11SurfactantTable 17.1 Factors That Affect Airway Resistance© 2013 Pearson Education, Inc.Mechanics of BreathingChapter 17Respiratory System Functions•Exchange of gases between the atmosphere and the blood•Homeostatic regulation of body pH•Protection from inhaled pathogens and irritating substances•Vocalization© 2013 Pearson Education, Inc.We also lose significant water and heat by ventilating thelungs, which must be compensated for by other physiologic processesRespiratory System Bulk Flow•Flow from regions of higher to lower pressure•Muscular pump creates pressure gradients•Resistance to flow–Diameter of tubes© 2013 Pearson Education, Inc.Figure 17.1EXTERNAL RESPIRATIONThe respiratory and circulatory systems coordinate to move oxygenand CO2 between the atmosphere and the cells by 4 processes (below).Exchange I:atmosphereto lung(ventilation)Exchange II:lung to bloodTransport ofgases inthe bloodExchange III:blood to cellsSystemiccirculationPulmonarycirculationAlveoliof lungsAirwaysCO2O2CO2O2O2CO2O2CO2CO2O2NutrientsCellularrespirationCellsATPRespiratory System Components•Conducting system, or airways•Alveoli (singular: alveolus)•Bones and muscle of thorax and abdomen© 2013 Pearson Education, Inc.Figure 17.2b ANATOMY SUMMARY – The Lungs and Thoracic CavityRight bronchusRight lungDiaphragmLeft bronchusLeft lungTracheaLarynxTongueNasal cavityPharynxVocal cordsEsophagusUpperrespiratorysystemLowerrespiratorysystemThe respiratory system is dividedinto upper and lower regions.Figure 17.2a ANATOMY SUMMARY – The Lungs and Thoracic CavityMuscles of the thorax, neck, and abdomencreate the force to move air during breathing.Sternocleido-mastoidsScalenesExternalintercostalsDiaphragmInternalintercostalsAbdominalmusclesMusclesofinspirationMusclesofexpirationFigure 17.4BRANCHING OF THE AIRWAYSConducting systemName DivisionDiameter (mm)How many?Cross-sectionalarea (cm2)TracheaPrimary bronchiSmallerbronchiBronchiolesAlveoliExchange system2412-236-1154321015-2210-151-100.5-10.32.51005  1031  1063-6  1088  1072  1041  104214Airways connect lungs to the external enviromentand warm, humidify, and filter inspired airAlveoli are the site of gas exchangeConditioning Air•Warming air to body temperature•Adding water vapor•Filtering out foreign material© 2013 Pearson Education, Inc.Figure 17.5a-b (1 of 8)Epithelial cells lining the airways and submucosalglands secrete saline and mucus.CiliatedepitheliumMovement of mucusMucus layerLumen of airwaySubmucosalglandCilia move the mucus layer toward the pharynx, removing trappedpathogens and particulate matter.BasementmembraneNucleus ofcolumnarepithelial cellGoblet cellsecretes mucus.CiliaWatery saline layerallows cilia topush mucustoward pharynx.Dust particleMucus layer trapsinhaled particles.The mucociliary elevatorFigure 17.2f ANATOMY SUMMARY – The Lungs and Thoracic CavityStructure of lung lobule. Each cluster of alveoli issurrounded by elastic fibers and a network capillaries.BronchioleBronchial artery,nerve and veinBranch ofpulmonaryveinElasticfibersCapillarybedsSmooth muscleLymphaticvesselAlveoliBranch ofpulmonary arteryAlveolar structureCapillaryType I alveolarcell for gasexchangeEndothelialcell of capillaryType II alveolarcell (surfactant cell) synthesizessurfactant.LimitedinterstitialfluidAlveolarmacrophageingests foreignmaterial.Elastic fibersFigure 17.2g ANATOMY SUMMARY – The Lungs and Thoracic CavityFigure 17.2h ANATOMY SUMMARY – The Lungs and Thoracic CavityExchange surface of alveoliBlue arrow represents gas exchangebetween alveolar air space and the plasma.AlveolarepitheliumNucleus ofendothelial cellCapillaryAlveolusEndotheliumPlasmaSurfactantAlveolarair spaceFusedbasementmembranesRBC0.1-1.5mPulmonary Circulation – high flow, low pressure system•Right ventricle  pulmonary trunk  pulmonary arteries  lungs  pulmonary veins  left atrium© 2013 Pearson Education, Inc.Pulmonary blood flow is equal to cardiac output and isControlled primarily by the factors regulating cardiac outputHypoxic vasoconstriction is a local mechanism for regulating thedistribution of pulmonary blood flow away from hypoxic alveoliImportant to match blood perfusion and ventilation in the lungFigure 17.14a (2 of 5)Normally perfusion of blood past alveoli is matched toalveolar ventilation to maximize gas exchange.ArterioleBronchioleLowoxygenbloodAlveoliAlveoliFigure 17.14b (3 of 5)Ventilation-perfusion mismatch caused byunder-ventilation alveoli.If ventilation decreasesin a group of alveoliPCO2 increases and PO2 decreases. Blood flowing past those alveoli does not get oxygenated.PCO2PO2Figure 17.14c (4 of 5)Local control mechanisms try to keep ventilationand perfusion matched.Decreased tissue PO2around underventilatedalveoli constricts theirarterioles, diverting bloodto better ventilated alveoli.Blood flow divertedto better ventilatedalveoliHypoxic vasoconstrictionRespiratory System Bulk Flow•Flow from regions of higher to lower pressure•Muscular pump creates pressure gradients•Resistance to flow–Diameter of tubes© 2013 Pearson Education, Inc.Figure 17.8a (3 of 5)At rest: Diaphragm is relaxed.Pleural spaceDiaphragmFigure 17.8b (4 of 5)Inspiration: Thoracic volume increases.Diaphragm contracts and flattens.Inspiration occurs when alveolar pressure decreasesVertebraeSternumRibSide view:“Pump handle” motion increases anterior-posterior dimensionof rib cage. Movement of the handle on a hand pump isanalogous to the lifting of the sternum and ribs.Figure 17.8-1 (1 of 5)Figure 17.8-2 (2 of 5)Front view:“Bucket handle” motion increases lateral dimension ofrib cage. The