Scanning Electron Microscopic Observation of Endothelial Surface of Heart and Blood Vessels

Abstract

Details of the endothelial surface of the heart and large blood vessels were first uncovered by the scanning electron microscope. The endothelial cells form folds running along the blood stream like rifling (or spiral) in the barrel of a gun. Endothelial cells were found to be equipped with intercellular bridges which are entirely new structures not reported before. The bridges were found on the inner surface of endothelial cells, but transmission electron microscopic analysis exhibited the presence of bridges between endothelial cells on the outer surface of endothelial cells. The protoplasm of endothelial cells was sometimes found to be continuous through the bridges. The bridges seem to control the size of clefts of the intercellular junction between vascular endothelial cells and to protect the cells from tearing at the junction. Scanning electron microscopic observation of uncoated specimens was shown to be useful in observation of intercellular junctions and intracellular organelles through the transparent cell membrane.