An electron microscopic study of rabbit and human myocardium provides further evidence of the existence of two distinct components of the sarcoplasmic reticulum. A thin-walled tubular system (termed longitudinal system) is arranged in anastomosing channels sur-surrounding each sarcomere and has transverse and possibly also longitudinal connections with the tubules of adjacent sarcomeres. A thick-walled tubular system traverses the myofiber transversely at the level of the Z lines of the myofibrils. The structure of these tubules very closely resembles that of deep sarcolemmal invaginations. Indeed, the membranes of the tubules appear to be continuous with the sarcolemma in favorable sections so that there seems to be an extension of the cell membrane and extracellular fluid to all depths of the myocardial fiber. Certain physiologic data which support this concept are discussed. The calculations of A. V. Hill comparing the kinetics of diffusion and the time-distance relationships between excitation and activation in frog sartorius muscle are reconsidered for cardiac muscle.
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1 February 1963
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February 01 1963
ON THE STRUCTURAL CONTINUITIES OF THE TRANSVERSE TUBULAR SYSTEM OF RABBIT AND HUMAN MYOCARDIAL CELLS
Douglas A. Nelson,
Douglas A. Nelson
From the Department of Laboratory Medicine, University of Minnesota Medical School, Minneapolis
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Ellis S. Benson
Ellis S. Benson
From the Department of Laboratory Medicine, University of Minnesota Medical School, Minneapolis
Search for other works by this author on:
Douglas A. Nelson
From the Department of Laboratory Medicine, University of Minnesota Medical School, Minneapolis
Ellis S. Benson
From the Department of Laboratory Medicine, University of Minnesota Medical School, Minneapolis
Received:
June 11 1962
Online ISSN: 1540-8140
Print ISSN: 0021-9525
Copyright, 1963, by The Rockefeller Institute Press
1963
J Cell Biol (1963) 16 (2): 297–313.
Article history
Received:
June 11 1962
Citation
Douglas A. Nelson, Ellis S. Benson; ON THE STRUCTURAL CONTINUITIES OF THE TRANSVERSE TUBULAR SYSTEM OF RABBIT AND HUMAN MYOCARDIAL CELLS . J Cell Biol 1 February 1963; 16 (2): 297–313. doi: https://doi.org/10.1083/jcb.16.2.297
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