Respiration医疗培训课件

1、Chapter 5 RespirationWhen you can not breath, nothing else matters Slogan of the American Lung Association1Respiration医疗10/3/2022Chapter 5 RespirationWhen youRespiration is the process by which the body takes in and utilizes oxygen (O2) and gets rid of carbon dioxide (CO2).2Respiration医疗10/3/2022Res

2、piration is the process by An Overview of Key Steps in Respiration3Respiration医疗10/3/2022An Overview of Key Steps in ReRespiration can be divided into four major functional eventsVentilation: Movement of air into and out of lungsGas exchange between air in lungs and bloodTransport of oxygen and carb

3、on dioxide in the bloodInternal respiration: Gas exchange between the blood and tissues4Respiration医疗10/3/2022Respiration can be divided intRespiratory System Functions Gas exchange: Oxygen enters blood and carbon dioxide leavesRegulation of blood pH: Altered by changing blood carbon dioxide levelsV

4、oice production: Movement of air past vocal folds makes sound and speechOlfaction: Smell occurs when airborne molecules drawn into nasal cavityProtection: Against microorganisms by preventing entry and removing themMetabolism: Synthesize and metabolize different compounds (Nonrespiratory Function of

5、 the Lung)5Respiration医疗10/3/2022Respiratory System Functions GSection I VENTILATION 6Respiration医疗10/3/2022Section I VENTILATION 6ROccurs because the thoracic cavity changes volumeInsipiration uses external intercostals and diaphragmExpiration is passive at rest, but uses internal intercostals and

6、abdominals during severe respiratory loadBreathing rate is 10-20 breaths / minute at rest, 40 - 45 at maximum exercise in adultsVentilation7Respiration医疗10/3/2022Occurs because the thoracic ca Thoracic Walls and Muscles of Respiration8Respiration医疗10/3/2022 Thoracic Walls and Muscles ofThoracic Volu

7、me9Respiration医疗10/3/2022Thoracic Volume9Respiration医疗1 Pleura10Respiration医疗10/3/2022 Pleura10Respiration医疗10/2/202Pleural fluid produced by pleural membranesActs as lubricantHelps hold parietal and visceral pleural membranes together11Respiration医疗10/3/2022Pleural fluid produced by pleu I. Alveola

8、r Pressure Changes During Respiration12Respiration医疗10/3/2022 I. Alveolar Pressure Changes Chest Wall(muscle, ribs)Principles of BreathingFunctional Unit: Chest Wall and Lung ConductingAirwaysDiaphragm(muscle)LungsGas Exchange Follows Boyles Law:Pressure (P) x Volume (V) = ConstantPleural CavityImag

9、inary Space betweenLungs and chest wallPleural CavityVery small space Maintained at negative pressureTransmits pressure changes Allows lung and ribs to slide 13Respiration医疗10/3/2022Chest WallPrinciples of BreathCWFollows Boyles Law: PV= CAt Rest with mouth open Pb = Pi = 0DPiAPSPbAirway OpenPrincip

10、le of Breathing114Respiration医疗10/3/2022CWFollows Boyles Law: PV= CAtCWFollows Boyles Law: PV= CAt Rest with mouth open Pb = Pi = 0Inhalation: Increase Volume of Rib cage Decrease the pleural cavity pressure- Decrease in Pressure inside (Pi) lungsDPiAPSPbAirway OpenPrinciple of Breathing215Respirati

11、on医疗10/3/2022CWFollows Boyles Law: PV= CAtCWFollows Boyles Law: PV= CAt Rest with mouth open Pb = Pi = 0Inhalation: Pb outside is now greater than Pi- Air flows down pressure gradient Until Pi = PbDPiAPSPbAirway OpenPrinciple of Breathing316Respiration医疗10/3/2022CWFollows Boyles Law: PV= CAtCWFollow

12、s Boyles Law: PV= CDPiAPSPbAirway OpenAt Rest with mouth open Pb = Pi = 0Exhalation: Opposite Process Decrease Rib Cage VolumePrinciple of Breathing417Respiration医疗10/3/2022CWFollows Boyles Law: PV= CDPCWFollows Boyles Law: PV= CAt Rest with mouth open Pb = Pi = 0Exhalation: Opposite Process Decreas

13、e Rib Cage Volume Increase in pleural cavity pressure - Increase PiDPiAPSPbAirway OpenPrinciple of Breathing518Respiration医疗10/3/2022CWFollows Boyles Law: PV= CAtCWFollows Boyles Law: PV= CAt Rest with mouth open Pb = Pi = 0Exhalation: Opposite Process Decrease Rib Cage Volume Increase Pi Pi is grea

14、ter than Pb Air flows down pressure gradient Until Pi = Pb againDPiAPSPbAirway OpenPrinciple of Breathing619Respiration医疗10/3/2022CWFollows Boyles Law: PV= CAtMechanisms of Breathing: How do we change the volume of the rib cage ?To Inhale is an ACTIVE process DiaphragmRib CageContractDiaphragmVolume

15、External Intercostal Muscles IntercostalsContractto LiftRibSpineRibsVolumeBoth actions occur simultaneously otherwise not effective20Respiration医疗10/3/2022Mechanisms of Breathing: How 21Respiration医疗10/3/202221Respiration医疗10/2/2022II Resistance of the VentilationElastic ResistanceInelastic Resistan

16、ce22Respiration医疗10/3/2022II Resistance of the Ventilati1. Elastic ResistanceA lung is an elastic sac. The thoracic wall is also an elastic element. So during inspiration the inspiratory muscles must expand the thoracic cage which are together with the elastic resistance.23Respiration医疗10/3/20221. E

17、lastic Resistance23RespiraThe elastic forces can be divided into two parts:Caused by the elastic tissue of the lung and the thoracic wall 2) Caused by surface tension of the fluid that lines the inside wall of the alveoli.The elastic forces caused by surface tension are much more complex. Surface te

18、nsion accounts for about two thirds of the total elastic forces in a normal lungs.24Respiration医疗10/3/2022The elastic forces can be diviSurface tension (表面张力）: a measure of the attraction force of the surface molecules per unit length of the material to which they are attached25Respiration医疗10/3/202

19、2Surface tension (表面张力）: a measSurface TensionForce exerted by fluid in alveoli to resist distensionLungs secrete and absorb fluid, leaving a very thin film of fluid.This film of fluid causes surface tension.H20 molecules at the surface are attracted to other H20 molecules by attractive forces.Force

20、 is directed inward, raising pressure in alveoli.26Respiration医疗10/3/2022Surface TensionForce exerted bWhat is Surface Tension ?Within Fluid All forces balanceAt surfaceUnbalanced forces Generate Tension27Respiration医疗10/3/2022What is Surface Tension ?WithiSurface TensionLaw of Laplace:Pressure in a

21、lveoli is directly proportional to surface tension; and inversely proportional to radius of alveoli.Pressure in smaller alveolus would be greater than in larger alveolus, if surface tension were the same in both.Insert fig. 16.1128Respiration医疗10/3/2022Surface TensionLaw of Laplace:CollapseExpandEff

22、ect of Surface Tension on Alveoli sizeAir Flow29Respiration医疗10/3/2022CollapseExpandEffect of SurfacSurfactant (表面活性物质）Phospholipid produced by alveolar type II cells.Lowers surface tension.Reduces attractive forces of hydrogen bonding by becoming interspersed between H20 molecules.Surface tension i

23、n alveoli is reduced.30Respiration医疗10/3/2022Surfactant (表面活性物质）PhospholipiArea dependence of Surfactant actionTensionAreaSurfactantIncrease AreaSalineSlider - Change Surface AreaSalineDecreaseAreaLow S/unit AreaHigh S/unit Area31Respiration医疗10/3/2022Area dependence of Surfactant Surfactant prevent

24、s alveolar collapse32Respiration医疗10/3/2022Surfactant prevents alveolar cVolume LRVPleural Pressure060- 30 cm H2O- 153Normal (with surfactant)Saline FilledWithout surfactantVolume-pressure curves of lungs filled with saline and with air (with or without surfactant)33Respiration医疗10/3/2022Volume LRVP

25、leural Pressure060-Physiology Importance of SurfactantReduce the work of breathingStabilize alveoliPrevent collapse and sticking of alveoliMaintain the dryness of the alveoliPrevent the edema of the alveoli34Respiration医疗10/3/2022Physiology Importance of SurfaComplianceDistensibility (Stretchability

26、, Elasticity):Ease with which the lungs can expand.The compliance is inversely proportional to elastic resistance Change in lung volume per change in transpulmonary pressure. DV/DP100 x more distensible than a balloon.Specific compliance (比顺应性, CL）: the compliance per unit volumeCL = pulmonary compl

27、iance/residual volume35Respiration医疗10/3/2022ComplianceDistensibility (Stre2. Inelastic ResistanceThe inelastic resistance comprises airway resistance (friction) pulmonary tissue resistance (viscosity and inertia). Of these the airway resistance is by far the more important both in health and diseas

28、e. It account for 80%-90% of the inelastic resistance. 36Respiration医疗10/3/20222. Inelastic Resistance36RespiAirway ResistanceAirway resistance is the resistance to flow of air in the airways and is due to : internal friction between gas molecules2) friction between gas molecules and the walls of th

29、e airways37Respiration医疗10/3/2022Airway ResistanceAirway resistTypes of Air Flow38Respiration医疗10/3/2022Types of Air Flow38RespirationLaminar flow is when concentric layers of gas flow parallel to the wall of the tube. The velocity profile obeys Poiseuilles Law39Respiration医疗10/3/2022Laminar flow is

30、 when concentrPoiseuille and ResistanceAirway Radius or diameter is KEY. radius by 1/2 resistance by 16 FOLD - think bronchodilator here!40Respiration医疗10/3/2022Poiseuille and ResistanceAirwaThe gas flow in the larger airways (nose, mouth, glottis, and bronchi) is turbulentGas flow in the smaller ai

31、rway is laminarBreath sounds heard with a stethoscope reflect the turbulent airflowLaminar flow is silent41Respiration医疗10/3/2022The gas flow in the larger aiAirway ResistanceAny factor that decreases airway diameter, or increases turbulence will increase airway resistance, eg:Rapid breathing: becau

32、se air velocity and hence turbulence increasesNarrowing airways as in asthma (哮喘）, parasympathetic stimulation, etc.Emphysema (肺气肿）, which decreases small airway diameter during forced expirationIncrease of the density and viscosity of the inspired gas also increase the airway resistance42Respiratio

33、n医疗10/3/2022Airway ResistanceAny factor thControl of Airway Smooth MuscleNeural controlAdrenergic beta receptors causing dilatationParasympathetic-muscarinic receptors causing constrictionNANC nerves (non-adrenergic, non-cholinergic)Inhibitory release VIP and NO bronchodilitationStimulatory bronchoc

34、onstriction, mucous secretion, vascular hyperpermeability, cough, vasodilation “neurogenic inflammation”43Respiration医疗10/3/2022Control of Airway Smooth MusclControl of Airway Smooth MuscleLocal factorshistamine binds to H1 receptors-constrictionhistamine binds to H2 receptors-dilationslow reactive

35、substance of anaphylaxis (过敏反应）- constriction-allergic response to pollenProstaglandins （前列腺速） E series - dilation Prostaglandins （前列腺素）F series - constriction 44Respiration医疗10/3/2022Control of Airway Smooth MusclControl of Airway Smooth Muscle (cont)Environmental pollutionsmoke, dust, sulfur dioxi

36、de, some acidic elements in smogElicit constriction of airwaysmediated by:parasympathetic reflexlocal constrictor responses45Respiration医疗10/3/2022Control of Airway Smooth MusclIII Assessment of the Pulmonary Ventilation46Respiration医疗10/3/2022III Assessment of the PulmonarI. Pulmonary Volume and Ca

37、pacity47Respiration医疗10/3/2022I. Pulmonary Volume and Capaci48Respiration医疗10/3/202248Respiration医疗10/2/2022Pulmonary VolumesTidal volume (潮气量）Volume of air inspired or expired during a normal inspiration or expiration (400 500 ml)Inspiratory reserve volume （补吸气量）Amount of air inspired forcefully af

38、ter inspiration of normal tidal volume (1500 2000 ml)Expiratory reserve volume （补呼气量）Amount of air forcefully expired after expiration of normal tidal volume (900 1200 ml)Residual volume （残气量，RV）Volume of air remaining in respiratory passages and lungs after the most forceful expiration (1500 ml in

39、male and 1000 ml in female)49Respiration医疗10/3/2022Pulmonary VolumesTidal volume 50Respiration医疗10/3/202250Respiration医疗10/2/2022Pulmonary CapacitiesA Capacity is composed of two or more volumesInspiratory capacity （深吸气量）Tidal volume plus inspiratory reserve volumeFunctional residual capacity （功能残气量

40、, FRC）Expiratory reserve volume plus the residual volumeVital capacity （肺活量, VC）Sum of inspiratory reserve volume, tidal volume, and expiratory reserve volume Total lung capacity （肺总量, TLC）Sum of inspiratory and expiratory reserve volumes plus the tidal volume and residual volume51Respiration医疗10/3/

41、2022Pulmonary CapacitiesA Capacity52Respiration医疗10/3/202252Respiration医疗10/2/2022RV/TLC Normally less than 0.25 Increase by the obstructive pulmonary disease (RV) Increase during the restrictive lung disease (TLC)53Respiration医疗10/3/2022RV/TLC53Respiration医疗10/2/2022Minute and Alveolar VentilationM

42、inute ventilation: Total amount of air moved into and out of respiratory system per minuteRespiratory rate or frequency: Number of breaths taken per minuteAnatomic dead space: Part of respiratory system where gas exchange does not take placeAlveolar ventilation: How much air per minute enters the pa

43、rts of the respiratory system in which gas exchange takes place54Respiration医疗10/3/2022Minute and Alveolar VentilatioDead SpaceArea where gas exchange cannot occurIncludes most of airway volumeAnatomical dead space (=150 ml)AirwaysPhysiological dead space= anatomical + non functional alveoli55Respir

44、ation医疗10/3/2022Dead SpaceArea where gas exchaBasic Structure of the LungVDA tube = Airway (Trachea Bronchi Bronchioles) NO GAS EXCHANGEDEAD SPACEA thin walled Sac = AlveolusBlood VesselsGAS EXCHANGEOCCURS HEREVAFormula: Total Ventilation = Dead Space + Alveolar Space VT = VD + VA 56Respiration医疗10/

45、3/2022Basic Structure of the LungVDAPhysiological = Anatomical Dead Space Dead Space + Similar Concept: Physiological Dead SpaceDiseased lungs:Healthy Lungs:BlockedVesselAdditional Dead Space Anatomical Dead Space = Airways (constant)VAVD57Respiration医疗10/3/2022Physiological = AnatomicaII. Measureme

46、nt of Expiratory Flow - FVC58Respiration医疗10/3/2022II. Measurement of Expiratory FVC - forced vital capacity (cont)Defines maximum volume of exchangeable air in lung (vital capacity)forced expiratory breathing maneuverrequires muscular effort and some patient trainingInitial (healthy) FVC values app

47、rox 4 litersslowly diminishes with normal aging59Respiration医疗10/3/2022FVC - forced vital capacity (cSignificantly reduced FVC suggests damage to lung tissuerestrictive lung disease (fibrosis，纤维化)constructive lung diseaseloss of functional alveolar tissue FVC volume reduction trend over time (years)

48、 is key indicatorIntra-subject variability factorsagesexheightethnicityFVC - forced vital capacity (cont)60Respiration医疗10/3/2022Significantly reduced FVC suggFEV1 - forced expiratory volume (1 second) Defines maximum air flow rate out of lung in initial 1 second intervalforced expiratory breathing

49、maneuverrequires muscular effort and some patient trainingFEV1/FVC rationormal FEV1 about 3 litersFEV1 needs to be normalized to individuals vital capacity (FVC)typical normal FEV1/FVC ratio = 3 liters/ 4 liters = 0.7561Respiration医疗10/3/2022FEV1 - forced expiratory volumStandard screening measure for obstructive lung disease FEV1/FVC reduction trend over time (years) is key indicatorcalculate % predicted FEV1/FVC (age and height normalized)Reduced FEV1/FVC suggests obstructive damage to lung airwaysepisodic, reversible by bronchodilator drugsprobably asthma (哮