Summary
1. The properties of the contractile mechanism of unstriated muscle have been studied by recording the contraction of heat killed muscle, produced by raising its temperature to 70° C.
2. The effects of heat show that the contractile mechanism of unstriated muscle consists of two components; in one the relaxation is active and in the other passive. The latter again consists of two parts one of which is activated by heat.
3. The thermal contraction of heat killed unstriated muscle resembles the phasic response of living muscle.
4. The thermal response of heat killed unstriated muscle shows staircase and fatigue effects. It increases with initial length up to a certain point, so that there is an optimum length of muscle for its production. These phenomena in living muscle are therefore properties of the contractile mechanism.
5. Starling’s law of the heart is also shown by thermal contraction of dead muscle.
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References
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—————.. Ibid., 1938b,94, 322.
—————..Proc. Ind. Acad. Sci., 1953,37, 114.
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—————.. Ibid., 1951b,33, 165.
—————.. Ibid., 1951b,33, 184.
—————.. Ibid., 1954b,40, 125.
—————.. Ibid., 1954c,40, 145.
----- ..Ibid., 1955a.
----- ..Ibid., 1955b.
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—————..Curr. Sci., 1954a,23, 126.
—————..Agra University Journ. Res., 1952,1, 135.
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Singh, S.I., Singh, I. Responses of the contractile mechanism of unstriated muscle. Proc. Indian Acad. Sci. 41, 173–182 (1955). https://doi.org/10.1007/BF03050088
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DOI: https://doi.org/10.1007/BF03050088