Esdin LS 2 Lec 9 Respiratory

Expiration no mucles elastic recoil of the lungs

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Unformatted text preview: ve expiration no mucles –  Elastic recoil of the lungs •  Active expiration –  Contraction of internal intercostals –  Contraction of abdominal muscles (causes diaphragm to be pushed up) compliance: balloon-like, ease in change in volume insured by elasticity and surfactant 9 4/21/13 Gas Transport •  How do gases cross the lung/blood media? diffusion •  How are gases transported in the blood? both capillaries and alveoli are lined w simple squamous cells Alveolar Perfusion Type II alveolar cell Type I alveolar cell Pulmonary surfactant Interstitial fluid Macrophage Alveolus Capillaries Capillaries 0.5 µm Erythrocyte 10 4/21/13 How Do Gases Cross? •  By Diffusion –  Both the capillaries and the alveoli are lined with simple squamous epithelium How Are Gases Transported? •  Once in the blood, oxygen is transported in two ways –  Dissolved in the plasma and erythrocytes –  Bound to hemoglobin 1.5% 98.5% 11 4/21/13 Erythrocytes high positive pull (Fe) negative (O) means Fe Hemoglobin polypeptide 12 4/21/13 Gas Transport Alveolus Capillary bed Alveolus O2 Erythrocyte Hb Alveolar type I cells Endothelial cells Game mechanism as Transport s Capillary bed Endothelial cells O2 Hb Erythrocyte O2 diffusion Tissue cells 13 4/21/13 Oxygen Transport •  Oxygen crosses from the alveoli to the plasma •  From plasma to erythrocytes where it binds to Hb •  Oxygen is then transported to cells where it is unloaded in the same way more active, more oxygen, need...
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