at the atrial side of the a-v junction the endocardial cells contain numerous bristle-coated vesicles , tubules of agranular endoplasmic reticulum and large inclusion bodies of moderate electron density , whereas at the ventricular side these cells are poor in bristle-coated vesicles and agranular endoplasmic reticulum , and the inclusion bodies are small and electron dense .
C0007634
cells
C0230789
agranular endoplasmic