. Human physiology. and,in return, the air parts with its elements to the blood. To comprehend this mysterious process, we must be acquainted withthe pulmonary apparatus, as well as with the properties of atmosphericair, and the mode in which the contact between it and the blood iseffected. 1. ANATOMY OF TUE KESPIRATORY ORGANS. The thorax or chest contains the lungs,—the great agents of respira-tion. It is of a conical shape, the apex of the cone being formed bythe neck, and the base by a muscle, which has already been referredto more than once,—the diaphragm. The osseous framework. Fig. 76, i
. Human physiology. and,in return, the air parts with its elements to the blood. To comprehend this mysterious process, we must be acquainted withthe pulmonary apparatus, as well as with the properties of atmosphericair, and the mode in which the contact between it and the blood iseffected. 1. ANATOMY OF TUE KESPIRATORY ORGANS. The thorax or chest contains the lungs,—the great agents of respira-tion. It is of a conical shape, the apex of the cone being formed bythe neck, and the base by a muscle, which has already been referredto more than once,—the diaphragm. The osseous framework. Fig. 76, is formed, posteriorly^ of twelvedorsal vertebrse; anteriorly,^ of the sternum, originally composed ofeight or nine pieces; and laterally,, of twelve ribs on each side, passingfrom the vertebraa to, or towards, the sternum. Of these, the sevenuppermost extend the whole distance from the spine to the breast-bone,and are called true or sternal^ and at times, vertebrosternal ribs. They EESPIEATOEY ORGANS. 269 ^^^li^. become larger as they descend, and are situate more obliquely in re-gard to the spine. The other five, called false or asternal^ do not pro-ceed as fer as the sternum; the cartilages of three of them join thatof the seventh true rib, whilst the two lowest have no union with thoseabove them, and are, therefore, called floating ribs. These false ribs Fig. 76. become shorter and shorter as wedescend; so that the seventh truerib may be regarded as the com-mon base of two cones, formed bythe true and false ribs respectively. The different bones constitutingthe thorax are so articulated as toadmit of motion, and thus of dilata-tion and contraction of the motion of the vertebrae oneach other is described under an-other head. It is not materiallyconcerned in the respiratory move-ments. The articulation of the ribswith the spine and sternum de-mands attention. They are articu-lated with the spine in two places,—at the capitulum or head, and atthe tubercle. In t
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Keywords: ., bookauthordungliso, bookcentury1800, bookdecade1850, bookyear1856
