. Embryology. Embryology; Embryology; genealogy. 254 EMBRYOLOGY Respiration of the embryo As more fat and carbohydrate become oxidized, the amount of oxygen which is taken up by the embryo increases. This increase is very rapid as de- velopment proceeds. If we plot the rate of oxygen consumption at different times during development we obtain a curve which rises very sharply, as illustrated in Figure 166. As time goes on, the rate of oxygen consumption increases rapidly, following a logarithmic curve. Similarly, the rate of carbon dioxide production increases; the tissues must get rid of carbo
. Embryology. Embryology; Embryology; genealogy. 254 EMBRYOLOGY Respiration of the embryo As more fat and carbohydrate become oxidized, the amount of oxygen which is taken up by the embryo increases. This increase is very rapid as de- velopment proceeds. If we plot the rate of oxygen consumption at different times during development we obtain a curve which rises very sharply, as illustrated in Figure 166. As time goes on, the rate of oxygen consumption increases rapidly, following a logarithmic curve. Similarly, the rate of carbon dioxide production increases; the tissues must get rid of carbon dioxide. Oxygen gets into cells by diffusion, and the amount of oxygen taken up is limited by the extent of the cell surface exposed to the gas. As the embryo in- creases in volume it is evident that some mechanism must be provided for increasing the amount of surface exposed to oxygen. Likewise, the carbon dioxide must leave the embryo by means of diffusion. In the frog an increased surface results from the development of fingerlike external gill filaments. Fig. 166. The rate at which oxygen is consumed by the develop- ing frog egg increases sharply with time. As growth and differentiation proceed, more and more oxidation of the stored foods takes place. This oxidation makes available the energy for development. TIME FROM FERTILIZATION. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Barth, Lester G. (Lester George), 1905-1979. New York, Dryden Press
Size: 1295px × 1929px
Photo credit: © Paul Fearn / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., boo, bookcentury1900, booksubjectembryology, booksubjectgenealogy
