. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. INVERTEBRATE CELL VOLUME CONTROL 407 stress, but with time in the reduced salinity will at least partially recover the original volume (Fig. 1). The recovery time course varies from species to species. In general, the more euryhaline an animal the more rapid the recovery. Osmoregulators may show a similar response or may simply swell less than predicted (see Oglesby, 1981, for a thorough review). These whole animal responses are the result of water balance mechanisms which function at two levels within an organism. First, th
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. INVERTEBRATE CELL VOLUME CONTROL 407 stress, but with time in the reduced salinity will at least partially recover the original volume (Fig. 1). The recovery time course varies from species to species. In general, the more euryhaline an animal the more rapid the recovery. Osmoregulators may show a similar response or may simply swell less than predicted (see Oglesby, 1981, for a thorough review). These whole animal responses are the result of water balance mechanisms which function at two levels within an organism. First, the extracellular systems mentioned above, bulk movement of extracellular water by the excretory system, ion transport by various epithelia, and integumental water permeability all function in some combination to remove the excess water (again, see Oglesby, 1981). In addition, the osmotic influx of water into the extracellular compartments results, perforce, in a dilution of the extracellular environment. This dilution places an osmotic stress on the cells. Thus, although it can not be distinguished by whole animal measurements, the second level of response is at each cell. All cells tested to date have some volume regulatory ability. Like the whole animal, when the isolated cell is exposed to a hypoosmotic stress, it swells. With time in the reduced osmotic concentration the cell returns toward its original volume (Fig. 2a, b). Few cells, if any, are able to recover the exact original volume. Rather, an incomplete volume regulation is the rule. The cells of euryhaline osmoconforming invertebrates, often naturally exposed several times daily to wide and rapid osmotic fluctuations, are excellent volume regulators, but the cells from invertebrate species have no monopoly on this response. Vertebrate cells also regulate volume albeit usually over comparatively narrow ranges of osmotic concentration (mammalian e _3 "o r= 130 o "o O 120- 110- 100-. A 30 60 90 Time(min) 120 I
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
