Connective Tissue

Connective tissue It may be defined as group of elements derived largely from embryonic mesoderm and composed of cells,fibres and amorphous substance(intercellur substance secreted by cells.

FUNCTION 1.Cells are widely scatterd 2.it possese- cells,fibres and ground substance 3.The intercellular substances are maximum w here the cellular substances are minimum 4.mesodermal in origin except the connective tissue of nervous system. 5.It has got both blood and nerve supply.

Connective tissue components 1Fibroblast 2macrophages 3 mast cells 4pigments cell

.5.plasma cells 6.fat cells 7.reticular cells 8wandering cells( cells from blood vessels) ---neutrophil,lymphocyte,,monocyte, eosinophil. B Matrin----- fibres---collagen,elastic, reticular .Ground substance(chemically it is protein polysacharide)--albumin,globulin,glycoprotein, mucopolysacharide, minerals,water.

Classification of connective tisse as seen in diagram

Functions of connective tisse 1.forms the structural framework of the body. 2.Binds the structure together and holds them in position. 3. Acts as a protective organ for internal structure. 4.support structures and provide rigidity. 5.act as a padding and serves as a pathway for vessels. 6.unite disimilar tissues e.g.muscle and bone 7.Play a role in limiting spread of localized infections healing process. 8.In repair of woulds. 9.The phagocytic cells of C.T, phagocytes foreign parties.

1.Fibroblasts .shape – fusiform or spindle .cytoplasm---pale .nucleus-large, oval, central .cytoplasm is basophilic. .Cells have branching process .Location: loose areolar tissue. FUNCTIONS -Synthesis of fibres. -Collagen -elastic -synthesis of ground substance . Helps in wound healing .

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MACROPHAGE(histocyte) . l shape- large,irregular .cytoplasm-course granules with vacoules. .nucleus—small and oval .smaller branching process. .location- loose areolar tissue,venous sinusoid of liver,brain, marrow. Functions::phagocytosis.

Mast cells shape-round or oval .cytoplasm- contain granules and basophilic .nucleus- centrally placed and small. .Location- Blood vessels,fibrous capsule of liver, synovial membrane. Functions: - to produce heparin,, histamin,,hyaluronic acid and 5-HT - play role in allergic reaction.

PLASMA CELLS .Shape and size– round or oval .cytoplasm:homogenous and highly basic .nucleus- eccentric and cartwheel appearance .location—in areas of chronic inflammation,connective tissues of most areas. Function--- to produce circulatory antibodies.

FAT CELLS Shape: round when single polyhedral when in groups(signet ring appearance) .cytoplasm– form this peripheral rim. .nucleus: eccentric . Location– adipose tissue, loose connective tissue. Function---- storage house of food materials(as fat).

Connective tissue fibers 1.Collagen fibres function . Run in straight or wavy bundles .individual fibre doesnot branch but a group of fibres may pass from one to another. .Each fibre is a collection of variable number of collagen fibrils which are fine threads. .Each fibril consists of a number of microfibrils. Distrubution--- tendon, aponeurosis,,fascia,, cartilage.

Elastic fibers Run singly .They branch and anastomose to from a

irregular

network .The fibres are thinner and tauter than collagen. .chemically consists of mucopolysaccharide and protein elastin. .Distrubtion– ligamenttum nuchae,,ligamentum flava,,internal elastic lamina of artery, lung, vocal cord.

Reticular fibres .THE Fibres are extremely thin. .They branch profusely and anastomose to form a network. .They are supposed to be immature collagen fibres. .Stain by silver salts. Distrubution : in close association with basal lamina, lymph node, spleen, bone marrow,liver, Kidney, endocrine, smooth muscle, endoneurium.

Loose areolar connective tisue . It is compoesd of cells ,fibres and ground substance . . All connective tissue cells are present( fibroblast, macrophage more common) . Consists of meshwork of thin collagen and elastic fibres interlacing in all directions to give a measure of both elasticity and tensile strength. The large meshes contain soft, pliable, semifluid ground substance and different connective tissue cells. Distrubution . Submucus coat– in g.I.t. and subserous tissue.. .Forms subcutaneous tissue where fat is absent---- eye lids, penis, scrotum. Labia.

Continued of areolar tissue .Also found between muscles, vessels and nerves forming their investing sheaths and connecting them with surrounding structures. .Interior of organs, binding together the lobes and lobules of compound glands. .Various coats of hollow viscera and muscle and nerve fibres.

Dense connective tissue It contains mainly fibres with some cells and little ground substance. A.White fibrous tissue---white in colour where collagen fibres– predominate. Cells are fewer in relation to loose areolar tissue. (a) Regular: collagen bundles--- arranged in parallel sequence. Distrubution– tendon,,ligament, aponeurosis. (b) Irregular: collagen bundles arranged in an interwining network. Distrubution—1.dermis of skin 2. Fibrous capsule of liver. 3.submucosa G.I.T. 4.Perichondrium, pericardium.

B.Yellow elastic tissue .elastic fibres predominate .yellow in colour. Distrubution: ligamentum nuchae, flava, vocal cords, coats of larger blood vessels

Specialized connective tissue 1.Reticular tissue—it comprises reticular fibres, cells, lymph node, spleen, liver, bone marrow. 2.mucous connective tissue: it is a form of loose c.t.., cells are fibroblasts, matrix rich in hyaluronic acid, wharton’s jelly, vitreous body of eye. 3. Adipose tissue: it consists of aggregation of fat cells. Types1. Yellow adipose tissue--- unilocular( large cells each containing single large fat droplet. 2. Brown adipose tissue– smaller cells each containing numerous fat droplets-----multilocular.