|
KMID : 0383119610090010047
|
|
Journal of Aerospace Medicine
1961 Volume.9 No. 1 p.47 ~ p.59
|
|
|
Physiological studies on the tolerance of each species of animals to negative g
|
|
|
|
|
Abstract
|
|
|
|
The tolerance of rabbits, mice, rats and pi: geons to negative g stress(tailward acceleration) were compared. The mathematical formulae expressing strength (magnitude of g) and duration(exposure time in minute) curve of each species of animals were constructed. To investigate the effect of g stress during negative g application, E E G and ECG tracings were observed. In the survived animals after exposure to negative g, general condition, and the changes of body weight were noted. Histopathological findings of animals that died after exposure to negative g were observed. On the tolerance of each species of animals to negative g, the relationship between the magnitude of g and exposure time (t) at 100 per cent survival is expressed as follows: rabbits; g= 6/t-0.73 - 2, pigeons; g= 12/t - 6.3, mice; g= 8/t- 0.2 - 7.5 rats; g= 8/t-0.2 + 4.5, where g=980 cm/sec2. The magnitude of tolerable g to negative acceleration in each species of animals is approximately the half of positive g which was previously reported. Negative tolerance is inversely related to body weight and the length of body dimension, and this relationship between tolerance and body size is identical to positive g tolerance. On the ECG tracing during exposure to negative g sinus tachycardia, ventricular rhythm were observed as time went on. On the EEG tracing tendency of synchronization, high voltage slow waves and disappearance of EEG were observed. After disappearance of EEG the heart beats of animals were still recorded regularly. It was considered that the tolerance to negative g is affected by anoxic endurance of the brain under circulatory disorder of blood and also depends upon the peripheral vascular resistance to increased blood pressure resulted from stagnation of blood due to disturbance of venous return caused by negative .
|
|
|
KEYWORD
|
|
|
|
|
|
FullTexts / Linksout information
|
|
|
|
|
|
Listed journal information
|
|
|
|
|