ELECTRON MICROSCOPY: VESSELS: VASCULAR: CARDIOVASCULAR: VESSEL: Capillary. (EM-labeled); RCH/AMC33153, Capillary (transverse section), two endothelial cell nuclei are visible in the section, four segments of endothelial cells form the circumference of the vessel, a red blood cell fills the capillary lumen, rat uterus. E-red bl