. A text-book of human physiology . tothe traction which strives to re-store it to its original form, withextreme slowness (Funke). Inthe series represented in a muscle kept perfused withblood was stimulated every Only the first ten ofevery fifty contractions are herereproduced, the six series rejire- senting all told some three hundred separate movements. When the intervalbetween stimuli is made still shorter, say second, as fatigue continues thedescending limb of the curve does not reach the base line, before it is met bythe following stimulus, and the curve becomes m
. A text-book of human physiology . tothe traction which strives to re-store it to its original form, withextreme slowness (Funke). Inthe series represented in a muscle kept perfused withblood was stimulated every Only the first ten ofevery fifty contractions are herereproduced, the six series rejire- senting all told some three hundred separate movements. When the intervalbetween stimuli is made still shorter, say second, as fatigue continues thedescending limb of the curve does not reach the base line, before it is met bythe following stimulus, and the curve becomes much like an incomplete a longer interval, say six seconds, the contraction is not prolonged, or onlyslightly so. and the reduction in the height of the curve is the only expressionof fatigue. The muscle of warm-hJooded animals, kept perfused with blood, show, accord-ing to Rollet, only this latter form of fatigue, with no material increase inthe duration of the contraction even when the interval between stimuli is verj. Fig. 177.—Changes in the character of the contractionproduced by fatigue, after Rollet. •This condition is called contracture—Ed. 442 THE FUNCTIONS OF CROSS-STRIATED MUSCLES short. Consequently in these muscles the above-mentioned incomplete tetani areentirely wanting. [According to F. S. Lee this difference in the mode of fatigue between theexcised muscles of cold-blooded and of warm-blooded animals is due to a realphysiological difference and not, as had been supposed by Sehenck and Lohmann,to a mere difference of temperature. Lee finds that the muscles of the formerexhibit the same characteristic slowing of the contraction process (cf. Fig. 178)both at low and at high temperatures (though at the high temperature to some-what less extent than at the low); whereas the muscles of the latter do notexliibit this phenomenon at either high or low temperatures. The poikilother-mal condition (cf. page 46) is more primitive than the homoiothermal, an
Size: 1455px × 1718px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, booksubjectphysiology, bookyear1
