where are mucosal associated lymphoid tissues present in the human body and why
oral passage salivary glands gastrointestinal tract breast skin thyroid lung nasopharyngeal tract eye
title: Mucosa-associated lymphoid tissue text: Mucosa-associated lymphoid tissue The mucosa-associated lymphoid tissue (MALT), also called mucosa-associated lymphatic tissue, is a diffuse system of small concentrations of lymphoid tissue found in various submucosal membrane sites of the body, such as the gastrointestinal tract, oral passage, nasopharyngeal tract, thyroid, breast, lung, salivary glands, eye, and skin. MALT is populated by lymphocytes such as T cells and B cells, as well as plasma cells and macrophages, each of which is well situated to encounter antigens passing through the mucosal epithelium. In the case of intestinal MALT, M cells are also present, which sample antigen from the lumen and title: Gut-associated lymphoid tissue text: Gut-associated lymphoid tissue Gut-associated lymphoid tissue (GALT) is a component of the mucosa-associated lymphoid tissue (MALT) which works in the immune system to protect the body from invasion in the gut. Owing to its physiological function in food absorption, the mucosal surface is thin and acts as a permeable barrier to the interior of the body. Equally, its fragility and permeability creates vulnerability to infection and, in fact, the vast majority of the infectious agents invading the human body use this route. The functional importance of GALT in body's defense relies on its large population of plasma cells, which are title: Nasal-associated lymphoid tissue text: Nasal-associated lymphoid tissue Nasal- or nasopharynx- associated lymphoid tissue (NALT) represents immune system of nasal mucosa and is a part of mucosa-associated lymphoid tissue (MALT) in mammals. It protects body from airborne viruses and other infectious agents. In humans, NALT is considered analogous to Waldeyer's ring. NALT in mice is localized on cartilaginous soft palate of upper jaw, it's situated bilaterally on the posterior side of the palate. It consists mainly of lymphocytes, T cell and B cell enriched zones, follicle-associated epithelium (FAE) with epithelial M cells and some erythrocytes. M cells are typical for antigen intake from mucosa. In title: Lymphatic system text: the mediastinum in the chest, neck, pelvis, axilla, inguinal region, and in association with the blood vessels of the intestines. Lymphoid tissue associated with the lymphatic system is concerned with immune functions in defending the body against infections and the spread of tumours. It consists of connective tissue formed of reticular fibers, with various types of leukocytes, (white blood cells), mostly lymphocytes enmeshed in it, through which the lymph passes. Regions of the lymphoid tissue that are densely packed with lymphocytes are known as "lymphoid follicles". Lymphoid tissue can either be structurally well organized as lymph nodes or may consist title: Mucosal immunology text: and its environment, a large amount of secondary lymphoid tissue is found here. The mucosa-associated lymphoid tissue, or MALT, provides the organism with an important first line of defense. Along with the spleen and lymph nodes, the tonsils and MALT are also considered to be secondary lymphoid tissue. The mucosal immune system provides three main functions: serving as the body's first line defense from antigens and infection, preventing systemic immune responses to commensal bacteria and food antigens (primarily food proteins in the Gut-associated lymphoid tissue, so-called oral tolerance), and regulating appropriate immune responses to pathogens encountered on a daily basis.