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16 Cards in this Set
- Front
- Back
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alveoli
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scattered in walls of respiratory bronchioles
continuous in walls of alveolar ducts which lead to termial alveolar sacs smallest units in which gas exchange occurs thin walled spheriodal air filled spaces |
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type I alveolar epithilial cells
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very flattened cells
cover majority of alveolar wall sit on basement membrane terminally differentiate ( cannot divide) allow gas diffusion across cytoplasm |
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type II alveolar epithilial cells
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cuboidal
cytoplasmic granules contain surfactant divide to replace type I and type II cells |
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interalveolar septa
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seperate alveoli
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alveolar pores
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allow passage of air between alveoli
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blood-air barrier
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between the air and the blood plasam, oxygen must diffuse across:
alveolar fluid alveolar epithlial cell basement membrane of alveolar epithelium basement membrane of capilliary endothelium capiliary endothilial cells |
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blood-air barrier ___ thick
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.2-2 mico meters
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once in plasma, oxygen is taken up by
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eryhtrocytes then binds to hemaglobin
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pulmonary macrophages are present in three location
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intravascular- assocaited with endothielium (pigs, ruminants)
interstital alveolar- function to clear alveolar surface; remove via trachea or via intersitium--> lymphatic system |
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pulmonary macrophages derived from
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heamopoetic stem cells (monocyte-macrophage lineage)
can proliferate localy also recruited from blood during infection |
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intralobular septa
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collagen and elastic fibers
blood vessels |
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pleura
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squamous/cuboidal epithileium overlying elastic and collagen fibers
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partial pressure
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the pressure exerted by a given gas in a mix of gases
found by mutiplying by the total pressure |
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alveolar air
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water vapor added to air suring inspiration --- change in partial pressure of gases, although total pressure remains the same
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partial pressure of gas in liquids
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determined by concentration of gas dissolved in the fluid
oxygen bound to hemaglobin does not contribute to PO2 in blood CO2 dissolved in blood undergoes following reaction CO2+H2O <--> H+ + HCO3- |
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DR = PD X A X DC / T
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DR- diffusion rate
PD-partial pressure gradient across tissue barrier A- surface area available for diffusion DC- diffusion coefficient T-thickness of tissue barrier |
