Gut-associated lymphoid tissue

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The digestive tract's immune system is often referred to as gut-associated lymphoid tissue (GALT) and works to protect the body from invasion. GALT is an example of mucosa-associated lymphoid tissue.

Contents 1 Function 2 Components 3 Additional images 4 External links

[edit] Function

About 70% of the body's immune system is found in the digestive tract. The GALT is made up of several types of lymphoid tissue that produce and store immune cells, such as T amd B lymphocytes, that carry out attacks and defend against pathogens.

New research indicates that GALT may continue to be a major site of HIV activity, even if drug treatment has reduced HIV count in the peripheral blood.^{[citation needed]}

The citations you are looking for that shows that GALT is a major site of HIV activity

Viral Suppression and Immune Restoration in the Gastrointestinal Mucosa of HIV Type 1-Infected Patients Initiating Therapy during Primary or Chronic Infection Journal of Virology, August 2006, p. 8236-8247, Vol. 80, No. 16 Moraima Guadalupe,1 Sumathi Sankaran,1 Michael D. George,1 Elizabeth Reay,1 David Verhoeven,1 Barbara L. Shacklett,1 Jason Flamm,4 Jacob Wegelin,3 Thomas Prindiville,2 and Satya Dandekar and AIDS. 2003 Jan 3;17(1):53-63.Multiple measures of HIV burden in blood and tissue are correlated with each other but not with clinical parameters in aviremic subjects.Anton PA, Mitsuyasu RT, Deeks SG, Scadden DT, Wagner B, Huang C, Macken C, Richman DD, Christopherson C, Borellini F, Lazar R, Hege KM.

[edit] Components

Lymphoid tissue in the gut is comprised of the following :

• Tonsils (Waldeyer's ring)
• Adenoids (Pharyngeal tonsils)
• Peyer's patches
• Lymphoid aggregates in the appendix and large intestine
• Lymphoid tissue accumulating with age in the stomach
• Small lymphoid aggregates in the oesophagus
• Diffusely distributed lymphoid cells and plasma cells in the lamina propria of the gut

[edit] Additional images

Lymphatics of colon.

Section of the human esophagus.

Transverse section of human vermiform process. X 20.

Section of mucous membrane of human rectum. X 60.

[edit] External links

• Histology at BU 12502loa - "Digestive System: Alimentary Canal: colon, taenia coli"
• Histology at BU 11102loa - "Digestive System: Alimentary Canal: esophageal/stomach junction"

v • d • e Anatomy of torso, digestive system: Gastrointestinal tract Upper GI: to stomach Mouth • Pharynx (nasopharynx, oropharynx, hypopharynx) • Esophagus • Crop Upper GI: stomach rugae – gastric pits – cardia/gland – fundus/gland – pylorus/gland – pyloric antrum – pyloric canal – greater curvature – lesser curvature – angular incisure Lower GI: intestines Small intestine: Duodenum (Suspensory muscle, Major duodenal papilla, Minor duodenal papilla) • Duodenojejunal flexure • Jejunum • Ileum • continuous (intestinal villus, crypts of Lieberkühn, circular folds) Junction: Vermiform appendix • Ileocecal valve Large intestine: Cecum • Colon (ascending colon, hepatic flexure, transverse colon, splenic flexure, descending colon, sigmoid colon) • continuous (taenia coli, haustra, epiploic appendix) Lower GI: termination Rectum: Houston valve • rectal ampulla • pectinate line Anal canal: anal valves • anal sinuses • anal columns • Hilton's white line Anus: Sphincter ani internus muscle • Sphincter ani externus muscle Lower GI: lymph GALT: Peyer's patches (M cells)

v • d • e Immune system: Lymphatic system (Lymph, Lymphocytes) Primary Bone marrow – Thymus (Hassall's corpuscles) Secondary: Spleen (blood) Hilum – Trabeculae Red pulp (Cords of Billroth, Marginal zone) White pulp (Periarteriolar lymphoid sheaths, Germinal center) Trabecular arteries – Trabecular veins Secondary: Lymph nodes (extracellular fluid) Subcapsular sinus – Paracortex – Lymph vessels – High endothelial venules – Germinal center Secondary: MALT (mucosa) GALT – Peyer's patches – Germinal center