Definitions

lymphoid tissue

lymphoid tissue

[lim-foid]

Cells, tissues, and organs composing the immune system, including the bone marrow, thymus, spleen, and lymph nodes. The most highly organized components are the thymus and lymph nodes, and the least organized are the cells that wander in the loose connective-tissue spaces under membranes lining most body systems, where they can establish lymph nodules (local lymphocyte production centre) in response to antigens. The most common lymphoid tissue cell is the lymphocyte. Others are macrophages, which engulf foreign materials and probably alter them to initiate the immune response, and reticular cells, which produce and maintain thin networks of fibres as a framework for most lymphoid organs. Seealso immunity; lymphatic system.

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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.

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 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 activity, even if drug treatment has reduced HIV count in the peripheral blood.

Components

Lymphoid tissue in the gut is comprised of the following :

Additional images

References

External links

  • - "Digestive System: Alimentary Canal: colon, taenia coli"
  • - "Digestive System: Alimentary Canal: esophageal/stomach junction"

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