[The human life cycle from a theoretical viewpoint].

In the view of theoretical considerations the human course of life is regarded as a generalized motion. It is made an attempt to define terms, such as chronological age, biological age and ageing. In the model of ageing irreversible alterations affecting the organism are described by a complex variable, called vitality, which represents the state of systems. The rate of vitality dV/dt and the biomorphosis of systems are equivalent terms.