(1) 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.
(2) A tissue is an aggregate of cells in an organism that have similar structure and function
The fundamental types of tissues in animals are epithelial, nerve, connective, muscle, and vascular tissues whereas in plants, they are the meristematic (apical meristem and cambium), protective (epidermis and cork), fundamental (parenchyma, collenchyma and sclerenchyma) and vascular (xylem and phloem) tissues. Tissues that work in unison to carry out a specific set of functions form an organ.
adenoid tissue - lymphoid tissue.
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 tissue.
fibrous tissue - the common connective tissue of the body, composed of yellow or white parallel fibers.
gelatinous tissue - mucous tissue (see - mucous membrane).
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.
indifferent tissue - undifferentiated embryonic tissue.
interstitial tissue - connective tissue between the cellular elements of a structure.
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.
tissue death see necrosis.
tissue edema an abnormal accumulation of tissue fluid.
tissue factor see tissue thromboplastin.
tissue fluid the extracellular fluid that constitutes the environment of the body cells. It is low in protein, is formed by filtration through the capillaries, and the excess drains away as lymph. See also interstitial fluid.
tissue inhibitors inhibitors of fibrinolysis; present in placenta.
indifferent tissue undifferentiated embryonic tissue.
tissue necrosis fever fever caused by pyrogens released by necrotic pyrogens.
tissue plasminogen activator see plasminogen activator.
tissue reacting agent substances that have a poorly defined but advantageous local effect on tissues.
tissue receptor site a cell receptor common to cells of a particular tissue.
tissue residue residues of chemical substances that are unacceptable to local pure food legislation especially sulfonamides, estrogens, chlorinated hydrocarbons, heavy metals. These are thought or known to have a deleterious effect on people eating or drinking the relevant animal product. See also chemical food residue.
tissue sensitivity the susceptibility of individual tissues to injury by x-ray. The injury may be by way of inflammation, necrosis or cessation of cell growth. Fast-growing tissues in which the cells have a high mitotic index are the most sensitive, especially gonads, germinative layer of skin and erythropoietic tissues.
supportive tissues cartilage and bone.
tissue therapy see glandular therapy.
tissue typing identification of tissue types for purposes of predicting acceptance or rejection of grafts and organ 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. White blood cells, particularly lymphocytes, are used for tissue typing. The acceptance of allografts depends particularly on the matching of MHC antigens. If the donor and recipient are not MHC identical, the allograft is rejected. See also typing.