T-TUBULE SYSTEM IN SPECIALIZED AND GENERAL MYOCARDIUM OF RAT

Google Scholar
  • 1 January 1978
    • journal article
    • research article
    • Vol. 127  (SEP) , 125-140
Abstract
Ultrastructural studies on the rat heart after horseradish peroxidase infiltration show that all cardiac muscle cells possess a T-system but that its complexity varies according to the heart region. It is most extensive in the general ventricular myocardium where there are primary, secondary and tertiary transverse tubules as well as longitudinal elements, and there are numerous couplings between the T-system and the sarcoplasmic reticulum. The T-system and associated couplings are less extensive in the atrium and in the atrioventricular conducting system. It is least developed in the nodes, particularly the sinuatrial node, where it is restricted to primary T-tubules. There are numerous couplings of the sarcoplasmic reticulum with the surface sarcolemma in all types of cardiac muscle cell; where intercalated discs occur, such couplings are associated with non-specialized parts of the disc.