lymphoid tissue

tissue /tis·sue/ (tish´u) an aggregation of similarly specialized cells which together perform certain special functions.

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adenoid tissue  lymphoid t.

adipose tissue  connective tissue made of fat cells in meshwork of areolar tissue.

areolar tissue  connective tissue made up largely of interlacing fibers.

bony tissue  bone.

brown adipose tissue  a thermogenic type of adipose tissue containing a dark pigment, and arising during embryonic life in certain specific areas in many mammals, including humans; it is prominent in the newborn.

cancellous tissue  the spongy tissue of bone.

cartilaginous tissue  the substance of cartilage.

chromaffin tissue  a tissue composed largely of chromaffin cells, well supplied with nerves and vessels; it occurs in the adrenal medulla and also forms the paraganglia of the body.

cicatricial tissue  the dense fibrous tissue forming a cicatrix, derived directly from granulation tissue.

connective tissue  the stromatous or nonparenchymatous tissues of the body; that which binds together and is the ground substance of the various parts and organs of the body.

elastic tissue , elastic tissue, yellow connective tissue made up of yellow elastic fibers, frequently massed into sheets.

endothelial tissue  endothelium.

epithelial tissue  epithelium.

erectile tissue  spongy tissue that expands and becomes hard when filled with blood.

extracellular tissue  the total of tissues and body fluids outside the cells.

fatty tissue  adipose t.

fibrous tissue  the common connective tissue of the body, composed of yellow or white parallel fibers.

gelatinous tissue  mucous t.

glandular tissue  an aggregation of epithelial cells that elaborate secretions.

granulation tissue  the newly formed vascular tissue normally produced in healing of wounds of soft tissue, ultimately forming the cicatrix.

gut-associated lymphoid tissue  (GALT) lymphoid tissue associated with the gut, including the tonsils, Peyer's patches, lamina propria of the gastrointestinal tract, and appendix.

indifferent tissue  undifferentiated embryonic tissue.

interstitial tissue  connective tissue between the cellular elements of a structure.

lymphadenoid tissue  tissue resembling that of lymph nodes, found in the spleen, bone marrow, tonsils, and other organs.

lymphoid tissue  a latticework of reticular tissue, the interspaces of which contain lymphocytes.

mesenchymal tissue  mesenchyme.

mucous tissue  a jellylike connective tissue, as occurs in the umbilical cord.

muscle tissue , muscular tissue the substance of muscle, consisting of muscle fibers, muscle cells, connective tissue, and extracellular material.

myeloid tissue  red bone marrow.

nerve tissue , nervous tissue the specialized tissue making up the central and peripheral nervous systems, consisting of neurons with their processes, other specialized or supporting cells, and extracellular material.

osseous tissue  the specialized tissue forming the bones.

reticular tissue , reticulated tissue connective tissue consisting of reticular cells and fibers.

scar tissue  cicatricial t.

sclerous tissues  the cartilaginous, fibrous, and osseous tissue.

skeletal tissue  the bony, ligamentous, fibrous, and cartilaginous tissue forming the skeleton and its attachments.

subcutaneous tissue  the layer of loose connective tissue directly under the skin.

white adipose tissue , yellow adipose tissue the adipose tissue comprising the bulk of the body fat.

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lymphoid tissue

n.

See lymphatic tissue.

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Lymphoid tissue

Sites within the body that produce cells of the immune system, including lymph nodes, bone marrow, and the thymus.

Mentioned in: MALT Lymphoma

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lymphoid tissue

Etymology: L, lympha, water; Gk, eidos, form; OFr, tissu

tissue that consists of lymphocytes on a framework of reticular cells and fibers, as the tonsils and adenoids.

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tissue [tish´u]

a group or layer of similarly specialized cells that together perform certain special functions.

adenoid tissue lymphoid tissue.

adipose tissue connective tissue made of fat cells in a meshwork of areolar tissue.

areolar tissue connective tissue made up largely of interlacing fibers.

bony tissue osseous tissue.

brown adipose tissue (brown fat tissue) brown fat.

bursa-equivalent tissue (bursal equivalent tissue) a hypothesized lymphoid tissue in nonavian vertebrates including human beings, equivalent to the bursa of Fabricius in birds: the site of B lymphocyte maturation. It now appears that B lymphocyte maturation occurs primarily in the bone marrow.

cancellous tissue the spongy tissue of bone.

cartilaginous tissue the substance of cartilage.

chordal tissue the tissue of the notochord.

chromaffin tissue a tissue composed largely of chromaffin cells, well supplied with nerves and vessels; it occurs in the adrenal medulla and also forms the paraganglia of the body.

cicatricial tissue the dense fibrous tissue forming a cicatrix, derived directly from granulation tissue; called also scar tissue.

connective tissue the tissue that binds together and is the support of the various structures of the body; see also connective tissue.

elastic tissue connective tissue made up of yellow elastic fibers, frequently massed into sheets.

endothelial tissue peculiar connective tissue lining serous and lymph spaces.

epithelial tissue a general name for tissues not derived from the mesoderm.

erectile tissue spongy tissue that expands and becomes hard when filled with blood.

fatty tissue connective tissue made of fat cells in a meshwork of areolar tissue.

fibrous tissue the common connective tissue of the body, composed of yellow or white parallel elastic and collagen fibers.

gelatinous tissue mucous tissue.

granulation tissue material formed in repair of wounds of soft tissue, consisting of connective tissue cells and ingrowing young vessels; it ultimately forms cicatrix.

gut-associated lymphoid tissue (GALT) lymphoid tissue associated with the gut, including the tonsils, Peyer's patches, lamina propria of the gastrointestinal tract, and appendix.

indifferent tissue undifferentiated embryonic tissue.

interstitial tissue connective tissue between the cellular elements of a structure.

lymphadenoid tissue tissue resembling that of lymph nodes, spleen, bone marrow, tonsils, and lymph vessels.

lymphoid tissue a latticework of reticular tissue whose interspaces contain lymphocytes.

mesenchymal tissue embryonic connective tissue composed of stellate cells and a ground substance of coagulable fluid.

mucous tissue a jellylike connective tissue, such as occurs in the umbilical cord. Called also gelatinous tissue.

muscular tissue the substance of muscle.

myeloid tissue red bone marrow.

nerve tissue (nervous tissue) the specialized tissue forming the elements of the nervous system.

osseous tissue the specialized tissue forming the bones.

reticular tissue (reticulated tissue) connective tissue composed predominantly of reticulum cells and reticular fibers.

scar tissue cicatricial tissue.

sclerous t's the cartilaginous, fibrous, and osseous tissues.

skeletal tissue the bony, ligamentous, fibrous, and cartilaginous tissue forming the skeleton and its attachments.

splenic tissue red pulp.

subcutaneous tissue the layer of loose connective tissue directly under the skin.

tissue typing identification of tissue types for purposes of predicting acceptance or rejection of grafts and transplants. The process and purposes of tissue typing are essentially the same as for blood typing. The major difference lies in the kinds of antigens being evaluated. The acceptance of allografts depends on the hla antigens (HLA); if the donor and recipient are not HLA identical, the allograft is rejected, sometimes within minutes. The HLA genes are located in the major histocompatibility complex, a region on the short arm of chromosome 6, and are involved in cell-cell interaction, immune response, organ transplantation, development of cancer, and susceptibility to disease. There are five genetic loci, designated HLA-A, HLA-B, HLA-C, HLA-D, and HLA-DR. At each locus, there can be any of several different alleles.



Each person inherits one chromosome 6 from the mother and one from the father; that is, each parent transmits to the child one allele for each kind of antigen (A, B, C, D, and DR). If the parents are different at both alleles of a locus, the statistical chance of one sibling being identical to another is one in four (25 per cent), the chance of being identical at one allele only (half-identical) is 50 per cent, and the chance of a total mismatch is 25 per cent.

Techniques for Tissue Typing. Histocompatibility testing involves several basic methods of assay for HLA differences. The most widely used method uses the polymerase chain reaction to compare the DNA of the person, organ, or graft being tested with known pieces of the genes encoding MHC antigens. The variability of these regions of the genes determines the tissue type of the subject.



Serologic methods are used to detect serologically defined antigens on the surfaces of cells. In general, HLA-A, -B, and -C determinants are primarily measured by serologic techniques. A second method, involving lymphocyte reactivity in a mixed lymphocyte culture, for determining HLA-D or lymphocyte-defined antigens, is now only rarely used.

Essentially, the serologic method is performed by incubating target lymphocytes (isolated from fresh peripheral blood) with antisera that recognize all known HLA antigens. The cells are spread in a tray with microscopic wells containing various kinds of antisera and are incubated for 30 minutes, followed by an additional 60-minute complement incubation. If the lymphocytes have on their surfaces antigens recognized by the antibodies in the antiserum, the lymphocytes are lysed. A dye is added to show changes in the permeability of the cell membrane and cellular death. The proportion of cells destroyed by lysis indicates the degree of histologic incompatibility. If, for example, the lymphocytes from a person being tested for HLA-A3 are destroyed in a well containing antisera for HLA-A3, the test is positive for this antigen group.

white adipose tissue (yellow adipose tissue) the adipose tissue composing the bulk of the body fat.

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lymphoid

resembling or pertaining to lymph or to tissue of the lymphatic system.

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bronchus-associated lymphoid tissue (BALT)

aggregations of B and T lymphocytes in the lower respiratory tract.

lymphoid cells

lymphocytes and plasma cells.

lymphoid foci

small foci of lymphoid tissue which occur in almost all parenchymatous organs in birds. The foci are not encapsulated and blend with the surrounding tissue.

lymphoid follicles

see lymph nodule.

lymphoid granuloma

one of the lesions in chronic follicular pharyngitis in the horse and a cause of persistent cough, difficulty in swallowing and a stertorous respiration.

gut-associated lymphoid tissue (GALT)

aggregations of mucosal-associated lymphoid tissue in the gastrointestinal tract, including adenoids, tonsils, Peyer's patches and lamina propria of the intestine; responsible for a local immune response to antigens.

lymphoid leukemia

see lymphatic leukemia.

lymphoid leukosis

a very rare primary tumor in mammals characterized by high blood lymphocyte counts. It is the most common form of the avian leukosis complex of diseases caused by avian retroviruses. Birds are affected between the ages of 14 to 30 weeks and show nonspecific signs of emaciation, inappetence and weakness, but many also have enlarged abdomens and a palpably enlarged liver. The primary lesion is the transformation of B lymphocytes in the lymphoid follicles of the bursa of Fabricius, but multiple metastatic lesions occur in the liver, spleen, etc.

mucosal-associated lymphoid tissue (MALT)

aggregations and organized lymphoid cells tissue found immediately beneath mucous membranes lining the respiratory, gastrointestinal and urogenital system.

lymphoid organs

primary lymphoid organs include the thymus and the bursa of Fabricius and its mammalian equivalent; secondary lymphoid organs include lymph nodes, spleen, Peyer's patches, etc.

skin-associated lymphoid tissues

include a group of non-activated T lymphocytes and Langerhans cells derived from lymphatic or hematopoietic tissues which have antigen-presenting properties; enable the skin to maintain a functional immunological relationship with the immune system. Called also SALT.

lymphoid system

the lymphoid tissue of the body, collectively; it consists of the bone marrow, thymus, lymph nodes, spleen, and gut-associated lymphoid tissue (tonsils, Peyer's patches).

lymphoid tissue

a lattice work of reticular tissue, the interspaces of which contain lymphocytes.

lymphoid tumor

see lymphoma, lymphosarcoma, thymic lymphoma, leukemia.