The encyclopædia britannica; a dictionary of arts, sciences, literature and general information . d rightauricle, (3) the slight indrawing of the chestwall. The impulse is recorded by placing asmall cup, or receiving tambour, over the spotwhere it is most evident, and connecting theinside of the cup by a tube to a recording tam-bour. The cup can be closed by a rubber dam,or an air-tight junction can be effected bypressing it upon the skin. The stroke of theheart is transmitted as a wave of compressionto the air within the system of recording tambour is brought to urite ona drum, m
The encyclopædia britannica; a dictionary of arts, sciences, literature and general information . d rightauricle, (3) the slight indrawing of the chestwall. The impulse is recorded by placing asmall cup, or receiving tambour, over the spotwhere it is most evident, and connecting theinside of the cup by a tube to a recording tam-bour. The cup can be closed by a rubber dam,or an air-tight junction can be effected bypressing it upon the skin. The stroke of theheart is transmitted as a wave of compressionto the air within the system of recording tambour is brought to urite ona drum, moved by clockwork, and covered witha paper smoked with lamp-black. From therecord so obtained we can obtain information as to the time rela-tions of the heart-beat, but no accurate information as to its energyor amount of contraction. Conus arteriosus Right anterior cusp of pulmonary valve Rigtt coronary arteryAnterior cusp of aortic Right posterior cusp of aortic finfundibular) Right fraarRiaal) cuspof tricuspid valve Po^terior cusp ot tricuspid valve Rrght ventricle. From Young and Robinson, Cunninghams Teit-Book of Armtomy. Fig. 9.—The Relation of the Heart to the Anterior Wall of the Thorax. I, II, III, IV, V, VI, the upper six costal cartilages. The movements of the heart consist of a series of contractionswhich succeed each other with a certain rhythm. The period ofcontraction is called the systole and that of relaxation jfj^ diastole. The two auricles contract and relax syn- ^gat^gfchronously, and these movements are followed by the ^^synchronous contraction and relaxation of the ventricles, ^g^^.Finally, there is a short period when the whole heart is indiastole. The whole series of movements is known as the carauic VASCULAR SYSTEM 933 cycle. Taking 75 as the average number of heart-beats per minute,each cardiac cycle wi occupy -8 seconds. Of this period auricular systole occupies • I second auricular diastole occupies •^ „ ventri
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectencyclo, bookyear1910
