General histology and cytology
Three dimensional arrangement of mitochondria and endoplasmic reticulum in the heart muscle fiber of the rat
Article first published online: 26 JAN 2005
Copyright © 1981 Wiley-Liss, Inc.
The Anatomical Record
Volume 200, Issue 2, pages 139–151, June 1981
How to Cite
Segretain, D., Rambourg, A. and Clermont, Y. (1981), Three dimensional arrangement of mitochondria and endoplasmic reticulum in the heart muscle fiber of the rat. Anat. Rec., 200: 139–151. doi: 10.1002/ar.1092000204
- Issue published online: 26 JAN 2005
- Article first published online: 26 JAN 2005
- Manuscript Accepted: 27 OCT 1980
- Manuscript Received: 13 AUG 1980
The three-dimensional arrangement of mitochondria and endoplasmic reticulum was studied in thick sections of the heart left ventricle fixed in glutaraldehyde and impregnated with the Ur-Pb-Cu technique and in thin sections of glutaraldehyde-fixed tissue post-fixed in potassium ferrocyanide-reduced osmium. Squarish flattened mitochondria, approximately the size of a sarcomere, were arranged in longitudinal columns in the clefts between the myofibrils. At the periphery of the fiber, the endoplasmic reticulum took the appearance of a subsarcolemmal network of plate-like and tubular cisternae running parallel to the cell surface. Between the myofibrils, the ER network formed longitudinally oriented repetitive units whose structure varied according to their position in relation to the A- or I- bands of the myofibrils. In front of the A-band, the endoplasmic reticulum appeared as a single layered network of anastomotic tubules compressed between the adjacent myofibrils. In front of the I-band, it formed a multilayered network the three-dimensional arrangement of which was dependent upon the presence or absence of the T-tubule. In the absence of the T-tubule, the ER cisternae were loosely anastomosed and occasionally displayed bulbous terminal swellings. In the presence of T-tubules, tubular ER cisternae were seen running parallel on both sides of the T-tubules and were continuous with sheetlike cisternae sandwiched between the distended T-tubule and adjacent extremities of longitudinally arranged mitochondria. These tubular or flattened cisternae were connected to each other by numerous bridging cisternae around the T-tubules.