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Morphological and biochemical correlates of skeletal muscle contractility in the cat. I. Histochemical and electron microscopic studies
Author(s) -
Van Winkle W. B.,
Schwartz A.
Publication year - 1978
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.1040970110
Subject(s) - contractility , endoplasmic reticulum , ultrastructure , fiber , fiber type , anatomy , chemistry , myofibril , biophysics , sarcoplasm , skeletal muscle , electron microscope , muscle fibre , biology , endocrinology , biochemistry , physics , organic chemistry , optics
Three cat hind limb muscles have been examined, histochemically and ultrastructurally, in a multiparameter correlative study of structure and function in skeletal muscle contractility. The soleus, a histochemically pure, slow‐twitch muscle possesses ultrastructural features which are, in many cases, significantly different from those of almost pure fast twitch caudofemoralis muscle. Although stereological analysis of fiber types indicates a correlation between speed of relaxation and volume of sarcoplasmic reticulum, morphological features such as fenestrated collars and triad morphology are identical in all fiber types. The fast twitch‐oxidative‐glycolytic fiber possesses features common to both slow twitch fibers (high mitochondrial content) as well as fast twitch fibers (high sarcoplasmic reticulum content) in addition to Z band width which falls in between these two fiber types. Sarcoplasmic microtubules have been described in all three fiber types in all muscles examined. They occur in predictable orientation and their possible function (s) is described.