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[Johann Conrad Peyer, Swiss anatomist, 1653–1712]
A group of diffuse lymphoid nodules in the mucosa of the small bowel. Part of the mucosa-associated lymphoid tissue (MALT), Peyer's patches detect and respond to foreign antigens in the gastrointestinal tract. Antibodies secreted by B cells in Peyer's patches provide a significant defense against ingested pathogens.