. Biology of the vertebrates : a comparative study of man and his animal allies. Vertebrates; Vertebrates -- Anatomy; Anatomy, Comparative. The Release of Energy 3S5 lowing conditions: (1) the blood that is to receive oxygen must be sepa- rated from the air by a retaining cellular wall; (2) the wall must be suffi- ciently permeable to permit easy osmosis of gases; (3) the wall must be kept moist in order to permit thinness and permeability without drying up upon exposure; (4) the total walls or respiratory surfaces must be extensive enough in area to insure an adequate osmosis of oxygen for th
. Biology of the vertebrates : a comparative study of man and his animal allies. Vertebrates; Vertebrates -- Anatomy; Anatomy, Comparative. The Release of Energy 3S5 lowing conditions: (1) the blood that is to receive oxygen must be sepa- rated from the air by a retaining cellular wall; (2) the wall must be suffi- ciently permeable to permit easy osmosis of gases; (3) the wall must be kept moist in order to permit thinness and permeability without drying up upon exposure; (4) the total walls or respiratory surfaces must be extensive enough in area to insure an adequate osmosis of oxygen for the organism concerned; and (5) a current of fresh air must be made to pass repeatedly or continuously across the respiratory surface. These conditions are met in a variety of ways by different animals. 4. Different Kinds of Respiratory Mechanisms In the more primitive aquatic forms, diffuse breathing through the sur- face of the body precedes localized breathing through specific respiratory organs, such as gills or lungs, although both methods may be employed simultaneously, as in amphibians. Diffuse breathing is a decided handicap, however, since the necessarily delicate integument in animals that employ this method is not only subject to mechanical injuries, but its possessor must remain under water in order to escape the disastrous effects of exposure to drying air. The two most successful breathing mechanisms among terrestrial animals are tracheal tubes and lungs. Tracheal tubes, which have been elaborated by the great special- ized host of insects, consist essentially of ramifying tubes of inturned integument that admit air to the immediate neighborhood of the blood within the body cavity (Fig. 315). Lungs are air sacs in intimate proximity to vascular networks, with elaborate modifications for increasing the respiratory surface without harmful exposure to the desic- cating effects of the outside air. In addition to the gills, skin, and lungs of verte- brates, the tracheal
Size: 1053px × 2375px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, booksubjectanatomycomparative, booksubjectverte
