[Comparative electron microscopic study of interalveolar septa in Arctic foxes and dogs].

Structure of the interalveolar septa in the lungs of typical representatives of the Arctic Zone--Arctic foxes--has been studied electron microscopically in comparison with those of dogs from the middle zone of West Siberia. Structure and parameters of the dog pulmonary septa correspond to modern notion on ultrastructure of the respiratory system in animals of middle latitudes. In the Arctic fox a certain combination of morpho-functional peculiarities is observed contributing to an increased diffuse power of the lungs. The capillary ultrastructure of the animal is considerably changed. capillaries with double aerohematic barrier make a greater part of the capillary network (57%), area of the barrier is nearly twice as large (in dogs--37%, in Arctic foxes--65%). A great amount of Cohn's pores in the Arctic boxes (twice as great as in the dogs) is a peculiar feature for the Arctic fox pulmonary septum. The morpho-functional peculiarities stated contribute to an increased diffuse rate and to better saturation of blood with oxygen.