5. ACID-BASE BALANCE
205
organs, especially to the function of excretory organs like the kidney.
The “buffer base” can be changed by a redistribution of electrolytes
between tissues, extracellular fluid, and plasma. In addition to the
regulatory mechanisms in mammals, in fish there is also an exchange
possible between the plasma and the surrounding seawater. Robin
et al. (1966) and Dejours (1966) point to the possibility of an active
excretion of bicarbonate by the gills. The gills also excrete ammonia
(Dejours et al., 1968), which in part is exchanged for sodium taken up
by the gills (Garcia Romeu and Motais, 1966). Long lasting exposure to
asphyxic conditions can produce an increase in hemoglobin, which is
not only observed in mammals but also in fish. All changes of variables belonging to the second group are recognized by the evaluation of the CO, combining curve or by the pH - log pco2 line. Generally
such changes are long-term.
( 3 ) There is only one quantity in this last group. This is the partial
pressure of C 0 2 which regulates the physically dissolved CO, and,
hence, according to the CO, combining curve, the pH of the arterial
blood. The pro, is adjusted by the effective irrigation of the gills since
for a given CO, production the pro, varies inversely with it. Ventilatory
changes of pco2 and pH are almost instantaneous and provide the basis
for short-term adaptations required, e.g., during muscular exercise.
Changes of the arterial pco, can be measured directly.
To put it in another way, we may also say that there are two principally different ways of regulating the acid-base balance. There is the
metabolic way, dealing chiefly with the buffer processes of the homogeneous type, and there is the respiratory way, dealing chiefly with the
buffer processes of the heterogeneous type. As an open system the fish
like all other animals is defended twofold against changes of the acidity
of its milieu intbrieur. This defense, however, appears less powerful in
fish than in mammals. Whether this is considered as a lower stage of the
phylogenetic development or as an adaptation to the ecological demands
of the aquatic life is a question the reader may decide.
REFERENCES
Albers, C. ( 1982). Die ventilatorische Kontrolle des Saure-Basen-Gleichgewichts in
Albers, C. (1966). Unpublished data.
Albers, C., and Pleschka, K. (1967). Effect of temperature on CO, transport in
Albers, C., and Pleschka, K. (1967). Unpublished data.
Albers, C., Pleschka, K., and Spaich, P. (1969). Chloride distribution between red
blood cells and plasma in the dogfish (Scyliorhinus canicula). Respiration
Physiol. 7, 295-299.
Hypothermie. Anaesthesirt 11, 43-51.
elasmobranch blood. Respiration Physiol. 2, 261-273.
205
organs, especially to the function of excretory organs like the kidney.
The “buffer base” can be changed by a redistribution of electrolytes
between tissues, extracellular fluid, and plasma. In addition to the
regulatory mechanisms in mammals, in fish there is also an exchange
possible between the plasma and the surrounding seawater. Robin
et al. (1966) and Dejours (1966) point to the possibility of an active
excretion of bicarbonate by the gills. The gills also excrete ammonia
(Dejours et al., 1968), which in part is exchanged for sodium taken up
by the gills (Garcia Romeu and Motais, 1966). Long lasting exposure to
asphyxic conditions can produce an increase in hemoglobin, which is
not only observed in mammals but also in fish. All changes of variables belonging to the second group are recognized by the evaluation of the CO, combining curve or by the pH - log pco2 line. Generally
such changes are long-term.
( 3 ) There is only one quantity in this last group. This is the partial
pressure of C 0 2 which regulates the physically dissolved CO, and,
hence, according to the CO, combining curve, the pH of the arterial
blood. The pro, is adjusted by the effective irrigation of the gills since
for a given CO, production the pro, varies inversely with it. Ventilatory
changes of pco2 and pH are almost instantaneous and provide the basis
for short-term adaptations required, e.g., during muscular exercise.
Changes of the arterial pco, can be measured directly.
To put it in another way, we may also say that there are two principally different ways of regulating the acid-base balance. There is the
metabolic way, dealing chiefly with the buffer processes of the homogeneous type, and there is the respiratory way, dealing chiefly with the
buffer processes of the heterogeneous type. As an open system the fish
like all other animals is defended twofold against changes of the acidity
of its milieu intbrieur. This defense, however, appears less powerful in
fish than in mammals. Whether this is considered as a lower stage of the
phylogenetic development or as an adaptation to the ecological demands
of the aquatic life is a question the reader may decide.
REFERENCES
Albers, C. ( 1982). Die ventilatorische Kontrolle des Saure-Basen-Gleichgewichts in
Albers, C. (1966). Unpublished data.
Albers, C., and Pleschka, K. (1967). Effect of temperature on CO, transport in
Albers, C., and Pleschka, K. (1967). Unpublished data.
Albers, C., Pleschka, K., and Spaich, P. (1969). Chloride distribution between red
blood cells and plasma in the dogfish (Scyliorhinus canicula). Respiration
Physiol. 7, 295-299.
Hypothermie. Anaesthesirt 11, 43-51.
elasmobranch blood. Respiration Physiol. 2, 261-273.