Peyer's patch

Peyer's patches are organized lymphoid follicles, named after the 17th-century Swiss anatomist Johann Conrad Peyer. They are part of the immune system, specifically the Gut-associated lymphoid tissue (GALT). Peyer's patches are most numerous in the ileum, the final section of the small intestine. They are also present in the jejunum and the appendix.

Structure

Peyer's patches are oval-shaped areas of raised lymphoid tissue facing the intestinal lumen. They are surrounded by a layer of epithelial cells and mucin-producing goblet cells. The patches contain follicles with germinal centers rich in B cells, along with T cells, macrophages, and dendritic cells.

Function

Peyer's patches play a crucial role in the immune response. They monitor intestinal bacteria populations and prevent the growth of pathogenic bacteria in the intestines. They generate memory lymphocytes and antibody-producing plasma cells. These cells migrate to other parts of the body and serve as a rapid response force against future infections.

Clinical significance

Peyer's patches can be a target for various diseases. For example, in typhoid fever, the Salmonella typhi bacteria invade the Peyer's patches, causing inflammation and possible perforation of the intestinal wall. In Crohn's disease, a chronic inflammatory condition of the intestines, Peyer's patches are often enlarged.

See also

• Mucosal immune system
• Gut flora
• Lymphatic system

External links

• Peyer's Patches at the US National Library of Medicine Medical Subject Headings (MeSH)