ELECTRON MICROSCOPY: GASTROINTESTINAL: GI: COLON: Microvillous, striate, or brush border, intestinal epithelial cell, glycocalyx, intestinal microorganisms. (EM-labeled); RCH/AMC171, mouse cecal epithelium, cytoplasmic granules may be evidence of immunoglobulin secretion. 1-intestinal microorganisms (bacteria), 2-glycocalyx, 3-immunoglobulin-containing granules, 4-mitochondria, 5-microvillus