. The biology of marine animals. Marine animals; Physiology, Comparative. RESPIRATION 191 present, is due to blood protein. In the coelomic fluids of Aplysia and Echinus, for example, there is little protein and buffering is slight (cf. Table , p. 64). Protein content is low in Urechis plasma, but haemo- globiniferous corpuscles are present and buffering is due largely to the latter. The blood of Urechis absorbs C02 by chemical combination up to about 20 mm Hg, above which the dissociation curve becomes parallel to that for H20 and transport capacity is exhausted. In bloods containing haem
. The biology of marine animals. Marine animals; Physiology, Comparative. RESPIRATION 191 present, is due to blood protein. In the coelomic fluids of Aplysia and Echinus, for example, there is little protein and buffering is slight (cf. Table , p. 64). Protein content is low in Urechis plasma, but haemo- globiniferous corpuscles are present and buffering is due largely to the latter. The blood of Urechis absorbs C02 by chemical combination up to about 20 mm Hg, above which the dissociation curve becomes parallel to that for H20 and transport capacity is exhausted. In bloods containing haemocyanin most of the C02 is combined with this pigment, and such bloods show high buffering capacity. Haemolymphs of Palinurus, Limulus and Sepia, for example, contain from 10-20 vols of C02. Usually marine. 20 30 40 50 60 10 SO 90 Carbon dioxide tension (mm Hg) 700 Fig. Carbon dioxide Dissociation Curves for Sea Water and Different Bloods Curves: 1: sea water; 2: Aplysia fasciata; 3: Octopus macropus; 4: Palinurus vulgaris; 5: Scomber scombrus; 6: Phoca vitulina. (From various sources.) gill-bearing animals are exposed to very low C02 tensions (C02 0-23 mm Hg) and utilize the steep portion of their dissociation curves (49, 130, 134). The reaction C02 + H20 ^ H2C03 is relatively slow and is often catalysed by an enzyme, carbonic anhydrase, found in tissues and cells. Carbonic anhydrase occurs in vertebrate erythrocytes and in many invertebrate tissues. Variable, often high, concentrations are found in gills of fishes, especially in the pseudobranch; in the gills of Loligo, Limulus, Homarus and Libinia (absent, however, in Palinurus); in gills of some polychaetes; and in mantle tissue of lamellibranchs and gastropods (50, 63, 107, 146). In animals with calcareous shells and skeletons, bivalves, Crustacea and starfish, the skeleton is an important source of buffer Please note that these images are extracted from scanned page images that may have been digital
Size: 1913px × 1306px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, booksubjectmarineanimals, booksubjectphysiology
