Tissue | Health Dictionary

A collection of cells similar in structure or function.


Tissue | Health Dictionary

Keywords of this word: Tissue


ADIPOSE TISSUE

Medical Dictionary

Adipose tissue, or fat, is a loose variety of ?brous tissue in the meshes of which lie cells, each of which is distended by several small drops, or one large drop, of fat. This tissue replaces ?brous tissue when the amount of food taken is in excess of the bodily requirements. Adipose tissue occurs as a layer beneath the skin and also around several internal organs. (See DIET; FAT; OBESITY.)... Medical Dictionary

CONNECTIVE TISSUE

Medical Dictionary

Sometimes called ?brous tissue, this is one of the most abundant tissues in the body, holding together the body’s many di?erent structures. Connective tissue comprises a matrix of substances called mucopolysaccharides in which are embedded various specialist tissues and cells. These include elastic (yellow), collagenous (white) and reticular ?bres as well as macrophages (see MACROPHAGE) and MAST CELLS. Assembled in di?ering proportions, this provides structures with varying functions: bone, cartilage, tendons, ligaments and fatty and elastic tissues. Collagenous connective tissue binds the muscles together and provides the substance of skin. It is also laid down in wound repair, forming the scar tissue. Contracting with time, connective tissue becomes denser, causing the puckering that is typical in serious wounds or burns. (See ADHESION; SCAR; WOUNDS.)... Medical Dictionary

CONNECTIVE TISSUE DISORDERS

Medical Dictionary

A group of generalised in?ammatory diseases that a?ect CONNECTIVE TISSUE in almost any system in the body. The term does not include those disorders of genetic origin. RHEUMATIC FEVER and RHEUMATOID ARTHRITIS were traditionally classi?ed in this group, as were those diseases classed under the outdated heading COLLAGEN DISEASES.... Medical Dictionary

ELASTIC TISSUE

Medical Dictionary

CONNECTIVE TISSUE which contains a profusion of yellow elastic ?bres. Long, slender and branching, these ?bres (made up of elastin, an albumin-like PROTEIN) ensure that the elastic tissue is ?exible and stretchable. The dermis layer of the skin, arterial walls and the alveolar walls in the LUNGS all contain elastic tissue.... Medical Dictionary

FIBROUS TISSUE

Medical Dictionary

See CONNECTIVE TISSUE.... Medical Dictionary

GAMGEE TISSUE

Medical Dictionary

A surgical dressing composed of a thick layer of cotton-wool between two layers of absorbent gauze, introduced by the Birmingham surgeon, Sampson Gamgee (1828–1886). Gamgee tissue has been a registered trademark since 1911.... Medical Dictionary

LYMPHOID TISSUE

Medical Dictionary

Tissue involved in the formation of LYMPH, lymphocytes (see LYMPHOCYTE), and ANTIBODIES. It consists of the LYMPH NODES, THYMUS GLAND, TONSILS and SPLEEN.... Medical Dictionary

TISSUE PLASMINOGEN ACTIVATOR (TPA, TPA)

Medical Dictionary

A natural PROTEIN that occurs in the body. It has the property of breaking down a THROMBUS in a blood vessel (see THROMBOLYSIS). It is e?ective only in the presence of FIBRIN and activates plasminogen, which occurs normally on the surface of the ?brin. TPA is an important thrombolytic treatment immediately after a myocardial infarction (see HEART, DISEASES OF).... Medical Dictionary

TISSUE TYPING

Medical Dictionary

The essential procedure for matching the tissue of a recipient in need of transplanted tissue or organ to that of a potential donor. Unless there is a reasonable match, the recipient’s immune system (see IMMUNITY) will reject the donor’s organ. The main factors that are relevant to an individual’s reaction to donor tissue are called histocompatability antigens (see ANTIGEN). These are mostly human leucocyte antigens (HLAs – see HLA SYSTEM) present on the surface of cells. HLAs are inherited and, like ?ngerprints, unique to an individual, although identical twins have identical HLAs and hence are perfect matches for TRANSPLANTATION procedures.... Medical Dictionary

TISSUES OF THE BODY

Medical Dictionary

The simple elements from which the various parts and organs are found to be built. All the body originates from the union of a pair of CELLS, but as growth proceeds the new cells produced from these form tissues of varying character and complexity. It is customary to divide the tissues into ?ve groups:

Epithelial tissues, including the cells covering the skin, those lining the alimentary canal, those forming the secretions of internal organs. (See EPITHELIUM.)

Connective tissues, including ?brous tissue, fat, bone, cartilage. (See under these headings.)

Muscular tissues (see MUSCLE).

Nervous tissues (see NERVE).

Wandering corpuscles of the BLOOD and LYMPH. Many of the organs are formed of a single

one of these tissues, or of one with a very slight admixture of another, such as cartilage, or white ?brous tissue. Other parts of the body that are widely distributed are very simple in structure and consist of two or more simple tissues in varying proportion. Such are blood vessels (see ARTERIES; VEINS), lymphatic vessels (see LYMPHATICS), lymphatic glands (see GLAND), SEROUS MEMBRANES, synovial membranes (see JOINTS), mucous membranes (see MUCOUS MEMBRANE), secreting glands (see GLAND; SALIVARY GLANDS; THYROID GLAND) and SKIN.

The structure of the more complex organs of the body is dealt with under the heading of each organ.... Medical Dictionary