Lower Respiratory Tract Bronchioles Small – 1mm or less No longer contain cartilage Continue Branching Terminal Bronchioles Last passages before aveoli Still have Cilia Alveoli – where gas exchange occurs Phagocytosis removes small particles
Lower Respiratory Tract Convey air to alveoli Clean air and remove particles by mucociliary elevator Macrophages in aveoli phagocytize foreign particles – last line of defense
Airflow in the Lungs 1º Bronchi 2 º Bronchi 3 º Bronchi Bronchioles Terminal Bronchioles Alveolus GAS EXCHANGE with Capillary Bed
Mechanism of Airflow Airflow is a result in changes of pressure between two systems System 1: the outer atmosphere System 2: the pressure within the alveoli How does pressure change within the alveoli?
Mechanisms of Airflow How does pressure change within the alveoli? Boyles Law: P 1/V (Changes in Volume result in changes in Pressure!!!!!) How does volume change within the alveoli?
Mechanism of Airflow How does volume change within the alveoli? Inspiration The diaphragm expands the thoracic cavity during quiet inspiration Deep inspiration is aided by the pectoralis minor, the sternocleidomastoid and the erector spinae muscles (external intercostals)
Mechanism of Airflow Expiration Quiet Breathing: Volume changes are not caused by muscular contraction, rather the elasticity of the lungs and ribs Deep expiration: internal intercostals, abdominal muscles
Alveolar Gas Exhange O 2 loads into RBC; CO 2 unloads into the alveoli Factors involved: Concentration gradients Solubility in H 2 O Membrane thickness Membrane area
Respiratory volumes tidal volume: air inhaled or exhaled in one quiet breath inspiratory reserve volume: air in excess of tidal inspiration that can be inhaled with maximum effort expiratory reserve volume: air in excess of tidal expiration that can be exhaled with maximum effort residual volume: air remaining in lungs after maximum expiration, keeps alveoli inflated
Spirometry Exercise Each group is to measure one members tidal and expiratory reserve volume. Record on front board, indicating gender. After all groups are done, average total to get class average tidal and expiratory reserve volume and compare to known averages.
Bronchioscopy Flexible tube with camera attached Used to identify blockages in bronchi and to biopsy tumors/growths