呼吸系统教学课件：05 airflow.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 4 Airflow in the Respiratory System,Reference,P42-48,P218-220,Resistance of the Ventilation,Elastic Resistance,Determined by the Compliance,Lung and Thoracic Cage Compliance,Inelastic Resistance,Airway Resistance,3,Inelastic Resistance,airway resistance,Friction,80%90%,pulmonary tissue resistance,viscosity and inertia,10%20%,4,Airway Resistance,the,resistance to,air flow in,the airways,due to,internal,friction,between gas,molecules,friction,between gas molecules and the walls of the airways,5,Types of Air Flow,6,Laminar and Turbulent Airflow,The gas flow in the larger airways(nose,mouth,glottis,and bronchi)is,turbulent,Breath,sounds heard with a stethoscope reflect the turbulent,airflow,G,as flow in the smaller airway is laminar,Laminar,flow is silent,7,Laminar flow,is when concentric layers of gas flow parallel to the wall of the tube.,The velocity profile obeys Poiseuille,s Law,8,Poiseuille and Resistance,Airway Radius or diameter is KEY.,radius by 1/2 resistance by 16 FOLD,think,bronchodilator here,!,9,Factors Determining Airway Resistance,Lung volume,Bronchomotor,tone,Airflow patterns,3.Air Flow Patterns,Laminar small airways,Turbulent nose,mouse and large airways,The more turbulence,the more,resistancee,Site of Airways Resistance,Obstruction of Airway in Disease,Blocking of the airway by secretions,Bronchitis,Reduction in airway diameter due to contraction of smooth muscle or swelling,Asthma,Bronchitis,Collapse of the airway due to,disruption,of the supporting parenchyma,Emphysema,