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...

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...