ABSTRACT
The paper discusses the application of direct techniques to the study of circulation--catheterization of the heart and central vessels in biomedical experiments with the participation of healthy volunteers and during examinations of pilots, athletes, etc. The experiments showed high informativeness and reliability of the techniques and demonstrated their applicability to the study of gravity effects on the circulation and metabolism of different organs of healthy men as applied to aerospace and clinical medicine. These investigations allow clinical modelling of hemodynamic and metabolic changes that may develop in various organs and tissues in weightlessness, development of pathogenetically substantiated countermeasures against its adverse effects, formulation of certain requirements for artificial organs whose function should be as close as possible to that of natural organs of a healthy man. The paper presents the protocol and results of the first study of the effects of short-term simulated weightlessness on the circulation and metabolism of various organs of a healthy man: brain, heart, lungs, liver, kidneys, and musculoskeletal formations of the lower limbs.