Confocal image of villi from the human small intestine. The finger-like shape increases the surface area of the intestine, improving the efficiency of food absorption. The intestinal crypts (enzyme se...

Human duodenal epithelium, at the level of the crypt. Fixation was performed in buffered formal-calcium. Peroxisomes are stained with DAB by their catalase activity at pH 10.5, postosmicated and embed...