Chapter 3. Measurements of Structural Parameters in Cardiac Muscle

  1. Ruth Porter and
  2. David W. Fitzsimons
  1. Sally G. Page

Published Online: 30 MAY 2008

DOI: 10.1002/9780470720066.ch3

Ciba Foundation Symposium 24 - Physiological Basis of Starling's Law of the Heart

Ciba Foundation Symposium 24 - Physiological Basis of Starling's Law of the Heart

How to Cite

Page, S. G. (1974) Measurements of Structural Parameters in Cardiac Muscle, in Ciba Foundation Symposium 24 - Physiological Basis of Starling's Law of the Heart (eds R. Porter and D. W. Fitzsimons), John Wiley & Sons, Ltd, Chichester, UK. doi: 10.1002/9780470720066.ch3

Author Information

  1. Biophysics Department, University College London

Publication History

  1. Published Online: 30 MAY 2008
  2. Published Print: 1 JAN 1974

ISBN Information

Print ISBN: 9789021940250

Online ISBN: 9780470720066

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Keywords:

  • cardidc tissues;
  • cardiac muscle;
  • skeletal muscle;
  • dehydration;
  • electron microscope

Summary

Earlier measurements of sarcomere lengths in cardiac tissue are reviewed, including measurements of the range of values in the intact heart and of the value corresponding to lmax in isolated preparations. The uncertainties which are inherent in such measurements due to shrinkage of the tissue during preparation for electron microscopy and to other factors are discussed and it is suggested that, because of these sources of error, many published values of sarcomere lengths are as much as 10–12% too low.

Some new measurements of the filament lengths in kitten papillary and frog atrial muscles have been made. The A filaments in both tissues have the same length as in vertebrate skeletal muscles (1.55–1.6 pm). The I filaments are longer than in frog skeletal muscles, being 1.0–1.1 pm in both frog and kitten cardiac muscles. Certain irregularities in the individual I filament lengths within any given sarcomere have been found in both cardidc tissues as well as others in the A filament lattice of the frog atrial muscle.