[Cytologic changes in the myocardia of rats trained to altitude hypoxia].

Rats trained to the high-altitude hypoxia displayed signs of intensification of both the plastic and lytic processes; one of these processes prevailed in different cells. There was no significant change in the mitochondrial and myofibrillar ratio. An increase of the relative volume of the microcirculatory bed on account of dilatation of small vessels without any increase of their count was noted.