ERRATA

Abstract

We examined the distribution and fine morphology
of small lymph channels in the rabbit heart, and particularly
in the ventrirular myocardium. Light microsropy showed
many small subepicardial lymphatics in both
ventricles and in the subendocardium of papillary
muscles and right side of the septum. By amtrast,
small lymphatics were scanty in the myocardium,
ventrirular endocardium and left portion of the septum.
Electron microsropy revealed that the endothelial
ultrastructure of these lymphatics was similar at different
sites. The cytoplasm exhibited frequent adluminal
expansions and amtained numerous micropinocytotic
vesicles opening both into the lumen and surrounding interstitium;
bundles of microfilaments were commonly arranged
in a parallel fashion. There were bilaminations
of the endothelial wall between which relatively dense,
finely granular material was seen. Intercellular amtacts
were characterized by cell superimpositions and interlockings,
specialized junctions and occasional marulae
adherentes. The basal membrane was disrontinuous and
often of variable thickness. In the surrounding amnective
tissue, thin filaments appeared adjacent to the abluminal surface of the endothelial wall. Although the fine structure of the walls of small lymphatics in the rabbit ventrirular myocardium was similar to that of small lymphatics at other sites, their distribution varied from other mammalian species.