The encyclopædia britannica; a dictionary of arts, sciences, literature and general information . aphragm squeezesthe abdominal contents andforces blood from the liver andcistern into the heart. Theseforces take the place of _ thesinus and are far more intra-abdominal pressuremay be raised on bending orstraining till it becomes equi-valent to the pressure of acolumn of mercury 80-100 (Keith). Under such con-ditions the pericardium preventsthe right side of the heartbeing over-distended with ven-ous blood. With these facts in view, we , .. ? tit. •„ can now describe the co
The encyclopædia britannica; a dictionary of arts, sciences, literature and general information . aphragm squeezesthe abdominal contents andforces blood from the liver andcistern into the heart. Theseforces take the place of _ thesinus and are far more intra-abdominal pressuremay be raised on bending orstraining till it becomes equi-valent to the pressure of acolumn of mercury 80-100 (Keith). Under such con-ditions the pericardium preventsthe right side of the heartbeing over-distended with ven-ous blood. With these facts in view, we , .. ? tit. •„ can now describe the complete course of a cardiac cycle. We willstart at the moment when the blood is pouring from the venaecavae and pulmonary veins into the two auricles I he auricles arerelaxed and their cavities open into the ventricles by the funnel-shaped apertures formed by the dependent segments of the tricuspidand mitral valves. The blood passes freely through these aperturesinto the ventricles. The small positive pressure which is alwayspresent in the venous cistern (aided by the respiratory forces). ?fcm nng A. Keith, ia Journal of Analomy ani Fhysiolosy. Fig. II.—Diagram of the VenousCistern from which the Heart isfilled. Theabdominal or infra-diaphragmatic part of the cis-tern is indicated in black; thethoracic or supra-diaphrag-matic is stippled.
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectencyclo, bookyear1910
