Gut-associated lymphoid tissue
Encyclopedia
Mucosa-associated lymphoid tissue
The mucosa-associated lymphoid tissue is the diffusion system of small concentrations of lymphoid tissue found in various sites of the body, such as the gastrointestinal tract, thyroid, breast, lung, salivary glands, eye, and skin.MALT is populated by lymphocytes such as T cells and B cells, as...
.
Function
The digestive tract is an important component of the body's immune systemImmune system
An immune system is a system of biological structures and processes within an organism that protects against disease by identifying and killing pathogens and tumor cells. It detects a wide variety of agents, from viruses to parasitic worms, and needs to distinguish them from the organism's own...
. In fact, the intestine possesses the largest mass of lymphoid tissue in the human body. The GALT is made up of several types of lymphoid tissue
Lymphatic system
The lymphoid system is the part of the immune system comprising a network of conduits called lymphatic vessels that carry a clear fluid called lymph unidirectionally toward the heart. Lymphoid tissue is found in many organs, particularly the lymph nodes, and in the lymphoid follicles associated...
that store immune cells, such as T and B lymphocytes, that carry out attacks and defend against pathogens.
New research indicates that GALT may continue to be a major site of HIV
HIV
Human immunodeficiency virus is a lentivirus that causes acquired immunodeficiency syndrome , a condition in humans in which progressive failure of the immune system allows life-threatening opportunistic infections and cancers to thrive...
activity, even if drug treatment has reduced HIV count in the peripheral blood.
Components
Lymphoid tissue in the gut comprises the following:- Tonsils (Waldeyer's ring)
- Adenoids (Pharyngeal tonsils)
- Peyer's patches
- Lymphoid aggregates in the appendixVermiform appendixThe appendix is a blind-ended tube connected to the cecum , from which it develops embryologically. The cecum is a pouchlike structure of the colon...
and large intestineLarge intestineThe large intestine is the third-to-last part of the digestive system — — in vertebrate animals. Its function is to absorb water from the remaining indigestible food matter, and then to pass useless waste material from the body... - Lymphoid tissue accumulating with age in the stomachStomachThe stomach is a muscular, hollow, dilated part of the alimentary canal which functions as an important organ of the digestive tract in some animals, including vertebrates, echinoderms, insects , and molluscs. It is involved in the second phase of digestion, following mastication .The stomach is...
- Small lymphoid aggregates in the esophagusEsophagusThe esophagus is an organ in vertebrates which consists of a muscular tube through which food passes from the pharynx to the stomach. During swallowing, food passes from the mouth through the pharynx into the esophagus and travels via peristalsis to the stomach...
- Diffusely distributed lymphoid cells and plasma cells in the lamina propriaLamina propriaThe lamina propria is a constituent of the moist linings known as mucous membranes or mucosa, which line various tubes in the body ....
of the gut
External links
- "Digestive System: Alimentary Canal: colonColon (anatomy)
The colon is the last part of the digestive system in most vertebrates; it extracts water and salt from solid wastes before they are eliminated from the body, and is the site in which flora-aided fermentation of unabsorbed material occurs. Unlike the small intestine, the colon does not play a...
, taenia coli
Taenia coli
The taenia coli are three separate longitudinal ribbons of smooth muscle on the outside of the ascending, transverse, descending and sigmoid colons. They are visible, and can be seen just below the serosa or fibrosa....
" - "Digestive System: Alimentary Canal: esophageal/stomach junction"