- : A tissue in medicine is not like a piece of tissue paper. It is a broad term that is applied to any group of cells that perform specific functions. A tissue in medicine need not form a layer. Thus, The bone marrow is a tissue; Connective tissue consists of cells that make up fibers in the framework supporting other body tissues; and Lymphoid tissue is the part of the body's immune system that helps protect it from bacteria and other foreign entities.
* * *A collection of similar cells and the intercellular substances surrounding them. There are four basic tissues in the body : 1) epithelium; 2) connective tissues, including blood, bone, and cartilage; 3) muscle t.; and 4) nerve t.. [Fr. tissu, woven, fr. L. texo, to weave]- adipose t. a connective t. consisting chiefly of fat cells surrounded by reticular fibers and arranged in lobular groups or along the course of one of the smaller blood vessel s. SYN: fat (1), fatty t. (1), white fat (1).- areolar t. loose, irregularly arranged connective t. that consists of collagenous and elastic fibers, a protein polysaccharide ground substance, and connective t. cells (fibroblasts, macrophages, mast cells, and sometimes fat cells, plasma cells, leukocytes, and pigment cells).- bronchus-associated lymphoid t. (BALT) patches of lymphoid tissues composed mainly of B and T lymphocytes and extending throughout the bronchial airways of the lung.- chondroid t. 1. in an adult, t. resembling cartilage; SYN: fibrohyaline t., pseudocartilage. 2. in an embryo, an early stage in cartilage formation.- chromaffin t. a cellular t., vascular and well supplied with nerves, made up chiefly of chromaffin cells; it is found in the medulla of the suprarenal glands and, in smaller collections, in the paraganglia.- connective t. the supporting or framework t. of the animal body, formed of fibrous and ground substance with more or less numerous cells of various kinds; it is derived from the mesenchyme, and this in turn from the mesoderm; the varieties of connective t. are: areolar or loose; adipose; dense, regular or irregular, white fibrous; elastic; mucous; and lymphoid t.; cartilage; and bone; the blood and lymph may be regarded as connective tissues the ground substance of which is a liquid. SYN: interstitial t., tela conjunctiva.- elastic t. a form of connective t. in which the elastic fibers predominate; it constitutes the ligamenta flava of the vertebrae and the ligamentum nuchae, especially of quadrupeds; it occurs also in the walls of the arteries and of the bronchial tree, and connects the cartilages of the larynx. SYN: elastica (2), tela elastica.- erectile t. a t. with numerous vascular spaces that may become engorged with blood. SYN: cavernous t..- fibrohyaline t. SYN: chondroid t. (1).- fibrous t. a t. composed of bundles of collagenous white fibers between which are rows of connective t. cells; the tendons, ligaments, aponeuroses, and some of the membranes, such as the dura mater.- Gamgee t. a thick layer of absorbent cotton between two layers of absorbent gauze, used in surgical dressings.- granulation t. vascular connective t. forming granular projections on the surface of a healing wound, ulcer, or inflamed t. surface. SEE ALSO: granulation.- gut-associated lymphoid t. (GALT) lymphoid t. of the gastrointestinal mucosa that contains both B and T cells. This t. is responsible for localized immunity to pathogens such as bacteria, viruses, and parasites.- hard t. 1. t. that has become mineralized; 2. t. having a firm intercellular substance, e.g., cartilage and bone.- interstitial t. SYN: connective t..- lymphatic t., lymphoid t. a three-dimensional network of reticular fibers and cells the meshes of which are occupied in varying degrees of density with lymphocytes; there is nodular, diffuse, and loose lymphatic t.. SYN: adenoid t..- mesonephric t. intermediate mesoderm situated in the thoracic and lumbar regions of the embryo or fetus; it develops into the mesonephros and associated structures.- metanephrogenic t. t. derived from the intermediate mesoderm caudal to mesonephric levels and concerned with the formation of the nephrons of the metanephros.- mucosa-associated lymphoid t. (MALT) a class of lymphoid t. comprising nodular aggregates found in association with the wet mucosal surfaces of the body such as those of the respiratory, digestive, and urinary systems.- mucous connective t. a type of connective t. little differentiated beyond the mesenchymal stage; its ground substance of glycoproteins is abundant and contains fine collagenous fibers and fibroblasts; in its most characteristic form, it appears in the umbilical cord as Wharton jelly. SYN: gelatinous t..- muscular t. a t. characterized by the ability to contract upon stimulation; its three varieties are skeletal, cardiac, and smooth. See muscle. SYN: flesh (2).- myeloid t. bone marrow consisting of the developmental and adult stages of erythrocytes, granulocytes, and megakaryocytes in a stroma of reticular cells and fibers, with sinusoidal vascular channels.- nasion soft t. the outer point of intersection between the nasion-sella line and the soft t. profile.- nervous t. a highly differentiated t. composed of nerve cells, nerve fibers, dendrites, and a supporting t. (neuroglia).- osseous t. a connective t., the matrix of which consists of collagen fibers and ground substance and in which are deposited calcium salts (phosphate, carbonate, and some fluoride) in the form of an apatite. SYN: bone t..- osteogenic t. a connective t. with the property of forming osseous t..- periapical t. the structures adjacent to a root apex, particularly the periodontal ligament and bone.- reticular t., retiform t. a t. in which the argyrophilic collagenous fibers form a network and that usually has a network of reticular cells associated with the fibers.- smooth muscle t. smooth muscle.- subcutaneous t. [TA] an irregular layer of loose connective t. immediately deep to the skin and superficial to the deep fascia, usually consisting primarily of a fatty layer [TA] (panniculus adiposus [TA]) which may also include a muscle layer [TA] (stratum musculosum [TA]) and/or a fibrous layer [TA] (stratum fibrosum [TA]), or it may occur as a membranous layer [TA] (stratum membranosum [TA]) only, being nearly devoid of fat (as in the auricles, eyelids, scrotum, and penis); it is penetrated by, and gains support from, skin ligaments [TA] (retinacula cutis [TA]) extending between the dermis and the deep fascia; cutaneous nerves and superficial vessels course within the subcutaneous t., with only their terminal branches passing to the skin; of the body's coverings, this layer varies most between sexes and in different nutritional states. Terminologia Anat omica [TA] has recommended that the terms “superficial fascia” and “deep fascia” not be used generically in an unqualified way because of variation in their meanings internationally. The recommended terms are “subcutaneous t. [TA] (tela subcutanea)” for the former superficial fascia, and “muscular fascia” or “visceral fasci viscera[is]) in place of deep fascia. SYN: tela subcutanea [TA], hypodermis, fascia superficialis, hypoderm, stratum subcutaneum, subcutis, superficial fascia.- subcutaneous t. of penis [TA] a superficial layer continuous with fascia perinei superficialis. SYN: fascia penis superficialis, superficial fascia of penis.- subcutaneous t. of perineum [TA] the membranous layer of the subcutaneous t. in the urogenital region attaching posteriorly to the border of the urogenital diaphragm, at the sides to the ischiopubic rami, and continuing anteriorly onto the abdominal wall. SYN: Colles fascia, Cruveilhier fascia, fascia perinei superficialis, membranous layer of superficial fascia of perineum (1), membranous layer of superficial fascia (1), superficial fascia of perineum.- trabecular t. of sclera [TA] the network of fibers (pectinate ligaments) at the iridocorneal angle between the anterior chamber of the eye and the venous sinus of the sclera; it contains spaces between the fibers that are involved in drainage of the aqueous humor, and is composed of two portions: the corneoscleral part (the part attached to the sclera) and the uveal part (the part attached to the iris). SYN: reticulum trabeculare sclerae [TA], Gerlach valvula, Hueck ligament, ligamentum anulare bulbi, pectinate ligaments of iridocorneal angle, pillar of iris, trabecular meshwork, trabecular network, trabecular reticulum, trabecular zone.
* * *tis·sue 'tish-(.)ü, 'tish-ə(-w), chiefly Brit 'tis-(.)yü n an aggregate of cells usu. of a particular kind together with their intercellular substance that form one of the structural materials of a plant or an animal and that in animals include connective tissue, epithelium, muscle tissue, and nerve tissue
* * *n.a collection of cells specialized to perform a particular function. The cells may be of the same type (e.g. in nervous tissue) or of different types (e.g. in connective tissue). Aggregations of tissues constitute organs.
* * *tis·sue (tishґoo) [Fr. tissu] an aggregation of similarly specialized cells united in the performance of a particular function. tissular adj
Medical dictionary. 2011.