Final answer:
Peyer's patches are large collections of lymphoid tissue found in the submucosa of the small intestine. They play a crucial role in immune responses against ingested substances and help protect against potential pathogens.
Step-by-step explanation:
Peyer's patches are large collections of lymphoid tissue found in the submucosa of the small intestine. They are a type of mucosa-associated lymphoid tissue (MALT).
Peyer's patches are important for immune responses against ingested substances and contain specialized endothelial cells called M cells that sample material from the intestinal lumen and transport it to nearby follicles for mounting adaptive immune responses to potential pathogens.