The laws and mechanics of circulation, with the principle involved in animal movement . ng considerably larger than in the right, whilethe walls of the ventricle are also thicker (Fig. 3d, vg., vd.);and as this is the rule, it must relate, of course, to specialfunctions in the organ f«or which they are the relative adjust-ments. The explanation is easy : From the very nature of the mechanics in respiration, it 130 PHYSIOLOGICAL ANATOMY. follows that during expiration and the production of highpressure in the alveoli a large outpour of blood mustoccur in the plexuses, the four wide, short pulmo
The laws and mechanics of circulation, with the principle involved in animal movement . ng considerably larger than in the right, whilethe walls of the ventricle are also thicker (Fig. 3d, vg., vd.);and as this is the rule, it must relate, of course, to specialfunctions in the organ f«or which they are the relative adjust-ments. The explanation is easy : From the very nature of the mechanics in respiration, it 130 PHYSIOLOGICAL ANATOMY. follows that during expiration and the production of highpressure in the alveoli a large outpour of blood mustoccur in the plexuses, the four wide, short pulmonary veins(Fig. 39, 13, 14, 15, 16) giving it ready egress ; hence thegreat relative size of the chambers which function as receiv-ing reservoirs, But Nature is utilitarian to the last degree,here as elsewhere. Thus, the number of the muscles in theleft ventricle, together with the augmented capacity of thechamber, increases its suction and lifting force correspond-ingly for aspirating the plexuses and pumping the blood intothe arterial system for producing the high pressure in the. Fig. 39.—Diagram of the Four Cavities of the Heart.—Bernard, od, right auricle ;vd, right ventricle ; og, left auricle ; vg, left ventricle. The arrows indicate thecourse of the blood. latter, the importance of which it would be difficult to over-estimate. Then, again, during inspiration, when blood tends to ac-cumulate in the plexuses from low pressure in the alveoli,it serves for continuing the stream, acting as a strong suction-force upon it. Last, but not least, during expiration, whenblood tends to accumulate in the right side of the heart fromhigh pressure in the alveoli, the augmented energy it gives tothe outpour acts as a pulling-force upon the venous blood for PHYSIOLOGICAL ANATOMY. 131 maintaining a current through the lungs. Hence, everythingworks together for the common good. But, unlike what ob-tains in the right side, the auriculo-ventricular opening is aclosed door during systol
Size: 1548px × 1614px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookde, booksubjectblood, booksubjectrespiration
