呼吸系统教学课件：03 elastic property.ppt

单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,*,Chapter 3,Elastic Properties of the Respiratory System,1,Reference-Textbook,P 29 40,P 210-218,P 471 475,Reference Course Website,3,4,An Overview of Key Steps in Respiration,5,Key Steps in Respiration,Ventilation,:Movement of air into and out of lungs,Gas exchange,between air in lungs and blood,Transport,of oxygen and carbon dioxide in the blood,Internal respiration,:Gas exchange between the blood and tissues,Newborn RDS:Signs and Syndrome,Baby Aldridge,Premature infant(28 weeks gestation),Breathing very fast,Dyspnea,Chest was indrawing with each breath,Making a grunting sound,Question,The mechanism?,Treatment and prevention,6,Outline,Part I Intrapleural Pressure and Mechanism of the Ventilation,Part II,Lung Compliance,Part III The Effect of Disease,7,Part I Intrapleural Pressure and Mechanism of the Ventilation,8,Occurs because the thoracic cavity changes volume,Insipiration,uses external intercostals and diaphragm,Expiration,passive at rest,uses internal intercostals and abdominals during severe respiratory load,Breathing rate is 10-20 breaths/minute at rest,40-45 at maximum exercise in adults,Ventilation,10,Mechanisms of Breathing:,How do we change the volume of the rib cage?,To Inhale is an ACTIVE process,Diaphragm,Rib Cage,Contract,Diaphragm,Volume,External Intercostal Muscles,IntercostalsContractto Lift,Rib,Spine,Ribs,Volume,Both actions occur simultaneously otherwise not effective,Flail Chest,（连枷胸）,11,12,Pleura,13,Pleural fluid produced by pleural membranes,Acts as lubricant,Helps hold parietal and visceral pleural membranes together,Intrapleural Pressure,14,Penumothorax,15,Penumothorax,胸腔闭式引流术,19,Alveolar Pressure Changes,During Respiration,20,Chest Wall,(muscle,ribs),Principles of Breathing,Functional Unit:Chest Wall and Lung,Conducting,Airways,Diaphragm,(muscle),Lungs,Gas Exchange,Follows Boyles Law:Pressure(P)x Volume(V)=Constant,Pleural Cavity,Imaginary Space between,Lungs and chest wall,Pleural Cavity,Very small space,Maintained at negative pressure,Transmits pressure changes,Allows lung and ribs to slide,21,CW,Follows Boyles Law:PV=C,At Rest with mouth open P,b,=P,i,=0,D,P,i,A,PS,P,b,Airway Open,Principle of Breathing,1,22,CW,Follows Boyles Law:PV=C,At Rest with mouth open P,b,=P,i,=0,Inhalation:,Increase Volume of Rib cage,Decrease the pleural cavity pressure-Decrease in Pressure inside(P,i,)lungs,D,P,i,A,PS,P,b,Airway Open,Principle of Breathing,2,23,CW,Follows Boyles Law:PV=C,At Rest with mouth open P,b,=P,i,=0,Inhalation:,P,b,outside is now greater than P,i,-Air flows down pressure gradient,Until Pi=Pb,D,P,i,A,PS,P,b,Airway Open,Principle of Breathing,3,24,CW,Follows Boyles Law:PV=C,D,P,i,A,PS,P,b,Airway Open,At Rest with mouth open P,b,=P,i,=0,Exhalation:Opposite Process,Decrease Rib Cage Volume,Principle of Breathing,4,25,CW,Follows Boyles Law:PV=C,At Rest with mouth open P,b,=P,i,=0,Exhalation:Opposite Process,Decrease Rib Cage Volume,Increase in pleural cavity pressure -Increase P,i,D,P,i,A,PS,P,b,Airway Open,Principle of Breathing,5,26,CW,Follows Boyles Law:PV=C,At Rest with mouth open P,b,=P,i,=0,Exhalation:Opposite Process,Decrease Rib Cage Volume,Increase P,i,Pi is greater than P,b,Air flows down pressure gradient,Until P,i,=P,b,again,D,P,i,A,PS,P,b,Airway Open,Principle of Breathing,6,27,Resistance of the Ventilation,Elastic Resistance,Determined by the Compliance,Lung and Thoracic Cage Compliance,Inelastic Resistance,Airway Resistance,28,Part II Lung Compliance,29,What is lung compliance?,Change in lung volume for each unit change in transpulmonary pressure=stretchiness of lungs,D,V/,D,P,Transpulmonary pressure,is the,difference in pressure between alveolar pressure and pleural pressure.,Compliance diagram of lungs,There are 2 different curves according to different phases of respiration.,The curves are called:,Inspiratory compliance curve,Expiratory compliance curve,Shows the capacity of lungs to“adapt”to small changes of transpulmonary pressure.,Hysteresis,（滞后现象）,How do lungs adapt and why?,Compliance of lungs occurs due to elastic forces,.,Elastic forces of the,lung tissue,itself,A,B,Elastic forces of the,fluid,that lines the inside walls of alveoli and other lung air passages,Elastin+Collagen fibres,Surface Tension,Why is B the most important mechanism?,Experiment:,By adding saline solution there is no interface between air and alveolar fluid.(B forces were removed),surface tension is not present,only elastic forces of tissue(A),Transpleural pressures required to expand normal lung=3x pressure to expand saline filled lung.,Conclusion of this experiment:,Tissue elastic forces(A),=represent 1/3 of total lung elasticity,Fluid air surface tension(B),=2/3 of total lung elasticity.,Surface tension,water molecules are attracted to one another.,The force of surface tension acts in the plane of the air-liquid boundary to shrink or minimize the liquid-air interface,In lungs=water tends to attract forcing air out of alveoli to bronchi=,alveoli tend to collapse(!),surface tension elastic force,Elastic contractile force of the entire lungs(forces B),Why are we talking about surfactant?,Surface active agent in water=reduces surface tension of water on the alveolar walls,Pure water(surface pressure),72 dynes/cm,Normal fluid lining alveoli,without,surfactant(surface pressure),50 dynes/cm,Normal fluid lining alveoli,with,surfactant,5-30 dynes/cm,36,Pulmonary surfactant,Phospholipid produced by alveolar type II cells.,Develop at 24 weeks gestation,Produces surfactant at 34 weeks,Lowers surface tension.,Reduces attractive forces of hydrogen bonding,by becoming interspersed between H,2,0 molecules.,Laplaces law,“The pressure inside a balloon is calculated by twice the surface tension,divided by the radius.”,Pressure to collapse generated by alveoli is inversely affected by radius of alveoli,the smaller a bubble,the higher the pressure acting on the bubble,Smaller alveoli have greater tendency to collapse,38,Collapse,Expand,Effect of Surface Tension on Alveoli size,Air,Flow,39,Surfactant prevents alveolar collapse,Physiology Importance of Surfactant,Reduces surface tension and elastic recoil,making breathing easier,Reduces the tendency to pulmonary edema,Equalize pressure in large and small alveoli,Produces hysteresis,which“props”alveoli open,40,Compliance of thorax and lung together,The compliance of lungs+thorax=1/2 of lungs alone,.,Part III The Effect of Disease,Lung fibrosis,（肺纤维化）,Emphysema(,肺气肿）,Respiratory Distress Syndrome(RDS)of the Newborn,（新生儿呼吸窘迫综合症）,42,Lung fibrosis,The lungs are stiffened,By the laying down of collagen and fibrin bundles,Compliance is reduced,43,Emphysema,Destroy of the parenchyma,Less elastic recoil,Compliance increase,44,Newborn RDS:Signs and Syndrome,Baby Aldridge,Premature infant(28 weeks gestation),Breathing very fast,Dyspnea,Chest was indrawing with each breath,Making a grunting sound,Question,The mechanism?,Treatment and prevention,45,Newborn RDS,Most common respiratory illness in NICU,Occur in premature neonate,Surfactant deficiency,Risk factors,Asphyxia,（窒息）,Male,Acidosis,DM mother,Relationship between Gestational Age and RDS Morbidity,gestational age,(wks),morbidity,(%),2830,70,3132,4055,3335,1015,36,15,窒息,低体温,剖宫产,糖尿病母亲婴儿（,IDM,）,早产,肺泡,PS,肺泡不张,PaCO,2,通气,V/Q PaO,2,严重酸中毒,肺毛细血管通透性,气体弥散障碍,透明膜形成,呼吸性酸中毒,代谢性酸中毒,collapsed alveoli filled with hyaline membranes,Chest X-ray,Ground glass appearance,Reticulogranular,air bronchograms,diffuse and symmetrical ground glass infiltrates,Reticulogranular with air bronchograms,Before PS,treatment,After PS,treatment,Treatment:,Surfactant Replacement,Home Work,：,Case Study,Mechanics of Breathing.pdf,Pulmonary Structure and Lung Capacities.pdf,Pneumothorax.pdf,54,