The laws and mechanics of circulation, with the principle involved in animal movement . Fig. 29.—Front View of the Human Trachea and its Smaller Divisions.—Gray. The circular arrangement in the muscles has plain import,the rhythmical expansions and contractions in the tubing call-ing for this : they simply elongate and contract, with inspira- 106 PHYSIOLOGICAL ANATOMY. tion and expiration, the wave of expansion extending fromabove downward to the air-cells, which are last affected, whilethe wave of contraction extends from below upward. Tn thisway, an energetic circulation is produced through
The laws and mechanics of circulation, with the principle involved in animal movement . Fig. 29.—Front View of the Human Trachea and its Smaller Divisions.—Gray. The circular arrangement in the muscles has plain import,the rhythmical expansions and contractions in the tubing call-ing for this : they simply elongate and contract, with inspira- 106 PHYSIOLOGICAL ANATOMY. tion and expiration, the wave of expansion extending fromabove downward to the air-cells, which are last affected, whilethe wave of contraction extends from below upward. Tn thisway, an energetic circulation is produced through the tubingfor respiratory purposes, and cleanliness is maintained. Ofcourse, it also effects elongation and contraction in the lungsduring inspiration and expiration, enabling them to expandoutward and downward during inspiration, and to contractinward and upward during expiration, thus producing the up-. Pig. 30.—Section through a Lateral Infundibulum.— Schulze. From the lung of anadult human being, after it had been filled with and hardened in alcohol containingacetic acid, a, entrance from the alveolar passage into the infundibulum ; theupper margin of the opening has been partially removed by the section, magnified^ ; b, b, nuclei of smooth muscular fibres, magnified *£ ; c, c, framework of elasticfibres. and-down action of the organs, or the to-and-fro movement inthe long axis of the body, for which suspension by the rootsfrom the spine so as to hang free in the pleural sacs,together with the copious secretions for lubricating them, isessential; therefore readily accounted for. Finally, externalto this cylinder of muscles, we have a thick coat of elasticand connective tissue fibres (as obtains in arteries), in whichthe cartilages are imbedded, the latter, however, fading out PHYSIOLOGICAL ANATOMY. 107 and disappearing in the bronchioles ; but not the elastic coat,which contin
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Keywords: ., bookcentury1800, bookde, booksubjectblood, booksubjectrespiration
