Ayettey A S, Navaratnam V
J Anat. 1978 Sep;127(Pt 1):125-40.
The T-tubule system in cardiac muscle cells has been investigated with the electron microscope in 10 adult rats after infiltration with horseradish peroxidase. All cardiac muscle cells possess a T-system, but its complexity varies according to the region of the heart. 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 (SR). The T-system and associated SR couplings are less extensive in the atrium and in the atrioventricular conducting system. It is least well developed in the nodes, particularly in the sinuatrial node, where it is restricted to primary T-tubules. There are numerous SR couplings with the sarcolemma in all types of cardiac muscle cells. Where intercalated discs occur, SR couplings are associated with non-specialized parts of the disc. The possible significance of these ultrastructural features in regard to the speed of conduction by myocardial tissues, and in the excitation-contraction sequence is discussed.
在用辣根过氧化物酶浸润10只成年大鼠后，利用电子显微镜对心肌细胞中的T小管系统进行了研究。所有心肌细胞都拥有一个T系统，但其复杂程度因心脏区域而异。在一般心室肌中最为广泛，那里有初级、次级和三级横小管以及纵向成分，并且T系统与肌浆网（SR）之间存在大量连接。T系统及相关的SR连接在心房和房室传导系统中不太广泛。在结区，尤其是窦房结中发育最差，在那里它仅限于初级T小管。在所有类型的心肌细胞中，肌浆网与肌膜之间都有大量连接。在闰盘出现的地方，SR连接与闰盘的非特化部分相关。讨论了这些超微结构特征在心肌组织传导速度以及兴奋 - 收缩序列方面的可能意义。
