The Sarcoplasmic Reticulum of Skeletal and Cardiac Muscle
This paper traces the development of our present concept of the structural organization of the sarcoplasmic reticulum in striated muscle and reviews the physiologic evidence for its participation in intracellular impulse conduction. Comparative observations are presented showing that this system of membrane-limited tubules is particularly well developed in exceptionally fast-acting skeletal muscles. These findings are interpreted as evidence supporting the hypothesis that the reticulum is involved in the coupling of excitation to contraction, but it is considered likely that it also has other important functions in muscle metabolism. The sarcoplasmic reticulum of cardiac muscle is found to be much less extensive and less precisely arranged in relation to the cross-banded pattern of the myofibrils, than it is in skeletal muscle. It is believed, nevertheless, that it may prove to have a significant role in the physiology of the myocardium.
- © 1961 American Heart Association, Inc.