Morphometrics of rapidly frozen goose lungs

摘要: To understand the structural basis of avian gas exchange better, we made a morphometric study domestic and Canada goose lungs. The volume glutaraldehyde-fixed lungs (30 cm3/kg body weight) was similar to that determined from silicone casts by Duncker (33 cm3/kg). examine finer structures, rapidly froze under physiologic conditions, fixed tissue samples freeze substitution procedure analyzed with stereological methods. From light micrographs about 55% lung is parabronchi in both species. Volume densities air capillaries, blood capillaries surface:volume ratios these same structures were electron micrographs. Our measurements agree those other laboratories. Gas surface area largest good flier (Canada goose) but birds had larger areas than comparably sized mammals. harmonic mean blood-gas barrier thickness smaller species (0.3 microns) Thus, membrane diffusing capacities for gases should be Pulmonary capillary transit time, as calculated normal levels cardiac output, are longer mammals allow more time equilibrium. Pleats folds frequently observed suggesting may not rigid previously thought volumes change conditions.