[Rhythms of the digestive system and the body's biological clocks].

A hierarchic system of short-period rhythms are supposed to exist in the gastro-intestinal tract (GIT). A periodical activity (PA) of the GIT was considered from the standpoint of its role in the control of intraintestinal transit. A hypothesis is proposed concerning the structure and mechanism of the PA rhythm clock. The daily interaction of own rhythms of the enterometa-sympathetic system with the food intake triggers the intramuscular oscillator, two physiologically significant signals of which (filling up of the stomach and transit to the colon) are under the control of higher nervous centers. On the basis of the intramuscular oscillator, a central also double one, is formed, and a mutual neuro-humoral interaction is established between them. Significance of this mechanism is emphasized not only for the GIT activity but as a "timer" for ultraradian rhythms as well.