[Analysis of the imperative stimulus restricting voluntary breath holding].
In 5 healthy young men, the maximal voluntary breath holding--was studied under conditions of different initial values of PACO2--after oxygen inhalation at ordinary minute volume of respiration or at hyperventilation, or after breathing with oxygen mixtures with 2, 4, 6, 8 or 10% CO2. PACO2 was recorded at the moment of resuming of the intercostal muscles electric activity and at the point of breaking up the apnoea. A mathematical model was constructed. The hypothesis of participation of two independent factors (chemo- and mechanoreceptive) in genesis of the imperative stimulus for breathing was checked. The data obtained suggest that, in fact, the only factor restricting the duration of voluntary breath holding--is the summed up in time chemoreceptive stimulation. The involuntary contractions of respiratory muscles observed during apnoea are, apparently, a connecting link in formation of the imperative stimulus which breaks up the cessation of breathing.
D000328:Adult; D002245:Carbon Dioxide; D002628:Chemoreceptor Cells / Q000502:physiology*; D004576:Electromyography; D006801:Humans; D007366:Intercostal Muscles / Q000502:physiology; D008297:Male; D008465:Mechanoreceptors / Q000502:physiology*; D010100:Oxygen; D012119:Respiration; D013997:Time Factors
D002245:Carbon Dioxide; D010100:Oxygen
K analizu imperativnogo stimula, ogranichivaiushchego proizvol'nuiu zaderzhku dykhaniia