Acid-Base Imbalance and Gas Exchange During Heavy Work1

Author(s):  
M. Scherrer
Keyword(s):  
1995 ◽  
Vol 198 (8) ◽  
pp. 1755-1763 ◽  
Author(s):  
J Harrison ◽  
N Hadley ◽  
M Quinlan

Many insects ventilate discontinuously when quiescent, exhibiting prolonged periods during which little or no gas exchange occurs. We investigated the consequences of discontinuous ventilation (DV) on haemolymph acid­base status and tested whether spiracular opening during DV is due to changes in internal gas tensions in the western lubber grasshopper Taeniopoda eques. At 15 °C, resting T. eques exhibited interburst periods of about 40 min. During the interburst period, haemolymph PCO2 rose from 1.8 to 2.26 kPa, with minimal acidification of haemolymph. Animals in atmospheres in which PCO2 was 2 kPa or below continued to exhibit DV, while atmospheres in which PCO2 was 2.9 kPa or above caused cessation of DV. These data indicate that accumulation of internal CO2 to threshold levels between 2 and 2.9 kPa induces spiracular opening in grasshoppers. In contrast to the situation in lepidopteran pupae, variation in atmospheric PO2 had no effect on interburst duration. Relative to lepidopteran pupae, the internal PCO2 of grasshoppers during DV is threefold lower, the PCO2 required for triggering spiracular opening is also threefold lower, and the open phase spiracular conductance is at least tenfold higher, demonstrating that considerable diversity exists in these aspects of insect respiratory physiology.


2019 ◽  
Vol 33 (S1) ◽  
Author(s):  
Christian Damsgaard ◽  
Monica McGrath ◽  
Chris M. Wood ◽  
Jeffrey G. Richards ◽  
Colin J. Brauner

Author(s):  
Michael I. Lindinger ◽  
George J.F. Heigenhauser

1999 ◽  
Vol 202 (3) ◽  
pp. 267-278 ◽  
Author(s):  
B. Bagatto ◽  
R.P. Henry

The dynamics of bimodal respiration, diving behaviour and blood acid-base status in the softshell turtle Trachemys scripta and the pond slider Apalone ferox were investigated at rest and under conditions of stress induced by exercise and forced submergence. During periods of forced submergence, only A. ferox doubled its aquatic gas exchange rate. Both A. ferox and T. scripta increased their aerial gas exchange profoundly following exercise and forced submergence, a pattern indicative of increased anaerobic respiration. Emersion duration increased significantly in A. ferox following forced submergence, and mean apnoeic time decreased significantly in A. ferox following exercise, indicating that a larger proportion of time at the surface was spent ventilating. Also, A. ferox maintained a one-breath breathing bout regardless of treatment. Submergence produced a respiratory acidosis in the plasma of approximately 0.2 pH units in magnitude in T. scripta and a mixed respiratory/metabolic acidosis of 0.4 pH units in A. ferox. Exercise induced an acidosis of 0.2 pH units of primarily metabolic origin in both species. Intra-erythrocyte pH was also reduced in both species in response to submergence and exercise. Both intracellular and extracellular acidoses were more severe and longer lasting in A. ferox after each treatment. Plasma [HCO3-] decreased by 25 % in both species following exercise, but only in A. ferox following submergence. Plasma lactate concentrations increased by equal amounts in each species following exercise; however, they returned to resting concentrations sooner in T. scripta than in A. ferox. A. ferox had significantly higher lactate levels than T. scripta following forced submergence as well as a slower recovery time. A. ferox, which is normally a good bimodal gas exchanger at rest, utilizes aerial respiration to a greater extent when under respiratory and/or metabolic stress. T. scripta, although almost entirely dependent on aerial respiration, is physiologically better able to deal with the respiratory and metabolic stresses associated with both forced submergence and exercise.


1989 ◽  
Vol 10 (04) ◽  
pp. 279-285 ◽  
Author(s):  
T. Yoshida ◽  
M. Udo ◽  
M. Chida ◽  
K. Makiguchi ◽  
M. Ichioka ◽  
...  

2010 ◽  
Vol 42 ◽  
pp. 40-50 ◽  
Author(s):  
M. VENGUST ◽  
H. STÄMPFLI ◽  
A. N. DE MORAES ◽  
F. TEIXEIRO-NETO ◽  
L. VIEL ◽  
...  

2018 ◽  
Vol 97 (5) ◽  
pp. 445-448
Author(s):  
Yury Yu. Byalovsky ◽  
S. V. Bulatetsky ◽  
V. A. Kiryushin ◽  
N. I. Prokhorov ◽  
V. N. Abrosimov ◽  
...  

The aim of the study was to evaluate the effect of the duration of training on the use of personal respiratory protective equipment on indices of pulmonary gas exchange. Simulation of conditions for the use of personal respiratory protective equipment was carried out at the inspiratory resistance of 40, 60, 70 and 80% Pmmax. The study included 38 healthy male subjects aged 20 to 36 years. According to the results of the study, under the use of personal protective equipment for the respiratory system, preliminary training was shown to be essential. In the subjects without preliminary training, the use of personal protective equipment was followed by a weak change in the nature of the respiratory pattern. After the preliminary training subjects had an adaptive rearrangement of the respiratory pattern, consisted of the decline in breathing movements as the respiratory resistance increased. Preliminary training to the exposure of additional resistance to breathing, altered pulmonary gas exchange and acid-base state of blood. The trained subjects had higher pCO2 blood values and lower values of pO2. They showed a greater deficit of buffer bases of plasma compared to untrained ones. This fact testified the preliminary training for the use of personal respiratory protective equipment (long-term adaptation) changed the gas composition and acid-base state of the blood to be a more economical mode of the discharge of buffer systems. On the basis of the data obtained, the preliminary training for increased respiratory resistance was suggested to be advisable before the using personal respiratory protective equipment.


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