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Unformatted text preview: Lecture 7 10/1/07 Respiration and Oxygen Transport 16/10/2007 20:30:00 Pathway of O 2 Transport ventilation (movement of air in and out of lungs) diffusion (pulmonary capillaries) convection diffusion medium gas exchange organ blood circulation (convection) tissue mitochondria Diffusion over short distances Bulk flow (convection) over long distances (Ficks) Diffustion Eq: Diffusion Rate = K A (C OUT C IN ) / L = K A * delta C / L K diffusivity constant (proportional to molecular weight) A surface area delta C: concentration difference L: barrier thickness (diffusion path) delta C / L = concentration gradient Design for Diffusion maximize surface area (A) for exchange minimize membrane thickness find effective concentration gradient Human Lung Anatomy branching tree-like distribution of airways, alveoli, blood vessels air moves through gradually smaller and smaller passageways alveoli: tiny sac-like endings, inflate and deflate during breathing to exchange gases w/ blood flowing thru capillaries in alveolar wall o reason for alveoli: increase surface area , get short diffusion path (L) o elastic, contain a protein elastin o surfactin makes alveoli more flexible o contain collagen o extremely large SA and thin air-blood barrier maximize diffusive...
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This note was uploaded on 04/29/2008 for the course LIFE SCIEN 9007 taught by Professor Georgev.lauder,andrewa.biewener,petert.ellison,anddaniele.lieberman during the Spring '08 term at Harvard.
- Spring '08