The oscillations of blood pressure in the chicken.

Abstract 1. 1. The classical oscillations described for the blood pressure in the chicken did not differ from those that have been studied on most vertebrates. The recorded arterial pressure is therefore not constant. 2. 2. There is an interdependence between the pressure in the circulatory system and respiratory movements in the chicken by the interplay of hemodynamic factors of thoracic origin. 3. 3. Many physiological factors induce blood pressure variations, such as the variations of cardiac output, the muscular work required or not required for any effort (normal or deep respiratory movements, gasping, respiratory gas and so on). 4. 4. However there often appears during the course of an experiment a fourth type of large oscillation which originates from asphyxia. 5. 5. When asphyxie conditions have set in, the reaction of the animal is that of hypertension. 6. 6. If vascular chemosensitivity appears hypothetical, that of the aerial passages seems, on the contrary, well developed.