An autopsy-based study was made of the microcirculatory bed (MCB) of human heart in ischemic heart disease and arterial hypertension in an age-related aspect. Changes in MCB and its time course were studied in experimental models. On the basis of the studies done and data from the published literature we elaborated a morphological classification of MCB which include the following stages: compensatory; initial pathologic changes with the adaptation being maintained at the same level as before; profound pathological changes at the background of lowered adaptation; decompensation. The classification outlined above may be used in examining autopsy and biopsy material (experimental or perioperative) as well as in clinical investigations designed to study the nail bed, bulbar, conjunctiva, rectal mucous membrane. Investigation into MCB changes will enable us to properly assess adaptive potential and prescribe pathogenically substantiated surgical, internal or complex health resort treatment.