. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. FREE ENERGY IN MUSCLE 147 is 11,000 calories (Meyerhof, 1944) and according to the theory discussed, this energy is needed for relaxation. According to the curve in Figure 1, the expenditure of energy in contraction reaches 11,000 calories at 47° in the frog and at 53° in the rabbit, and exceeds 11,000 calories above these temperatures. If the theory is cor- rect, therefore, the muscle should be unable to relax at these temperatures and should persist in the full)' contracted state. In the frog, experiments were performed in
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. FREE ENERGY IN MUSCLE 147 is 11,000 calories (Meyerhof, 1944) and according to the theory discussed, this energy is needed for relaxation. According to the curve in Figure 1, the expenditure of energy in contraction reaches 11,000 calories at 47° in the frog and at 53° in the rabbit, and exceeds 11,000 calories above these temperatures. If the theory is cor- rect, therefore, the muscle should be unable to relax at these temperatures and should persist in the full)' contracted state. In the frog, experiments were performed in the following way: the sartorius of Rana pipiens was provided with a ligature at both ends, was excised and loaded in one series with 2 g. (Fig. 4, circles) and in another series with 20 g. (triangles). The length between ligatures was measured and the muscle dipped into Ringer solution of varying temperature. Above 40° a rapid contraction ensued which was measured at the end of the second minute. The contraction reached its maximum at 47° C. The muscle remained in this maximally contracted state. The gradual lengthening at higher temperatures is due to the denaturation which takes place above 47° C. rather rapidly. 12000 10000 8000 6000 4000 20OO. FIGURE 4. Heat contracture in the frog sartorius. The coordinate net corresponds to the right-hand side of Figure 1. The sloping straight line is the A F curve, and corresponds to the left-hand side ordinate. The points mark per cent of shortening and relate to the right-hand side ordinate of Figure 4. Abscissa : temperature in centrigrades. FIGURE 5. Same as Figure 2. Strips of the musculus gracilis of the Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Marine Biological Laboratory (Woods Hole, Mass. ); Marine Biological Laboratory (Woods Hole, Mas
Size: 1702px × 1469px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
