Connective Tissue

1. Connective Tissue

2. The term connective tissue is applied to a tissue which fills the spaces between more specialized elements and serves to hold them together and support them. DEFINITION

3. 1. Ordinary Connective tissue 2. Mucoid tissue 3. Special Connective tissue Types

4. Made up of • Cells - fixed - wandering • Intercellular matrix - ground substance - fibres 1. Ordinary Connective tissue

5. 1. Collagen fibres 2. Elastic fibres 3. Reticular fibres Fibres of Connective Tissue

6. Made up of wavy bundles of collagen fibrils which run in various bundles. • Bundles split into branches, individual fibres do not branch. • Synthesized by fibroblasts. • Stainspinkwith H & E Staining. • In Unstained preparations looks white – white fibres. • Can resist considerable tensile forces. 1. Collagen fibres

7. Chemically, protein is COLLAGEN, made up of molecules of TROPOCOLLAGEN

9. Type I - in tendons, ligaments - large diameter (250 nm) - prominent striations • Type II - in hyaline cartilage - smaller, less prominent striations • Type III - reticular fibres • Type IV - in basal laminae, lens capsule - short filaments which form sheets Types Of Collagen Fibres More than 20 types of fibres have been identified

10. Run singly not in bundles • The individual fibres branch & anastomose with one another. • When fibres are cut ,the ends retract & recoil. • Synthesized by fibroblasts • Take a weak pink stain with H & E. • Unstained fibres appear yellow in colour. • Thinner than collagen fibres (0.1- 0.2 nm) • Can be stretched like a rubber band & return to original length. 2. Elastic fibres

11. Chemically, protein is ELASTIN, made up of molecules of TROPOELASTIN. Also contains a glycoprotein FIBRILLIN.

13. Very fine branched fibres that are characteristically arranged in delicate networks. • The networks hold the cells in place. • Seen in lymphoid organs, liver & bone marrow. • Do not take up H & E stain, can be stained by silver salts, so also called as ARGENTOPHIL FIBRES. • Synthesized by reticular cells or probably by fibroblasts. 3. Reticular fibres

15. FIXED CELLS - fibroblasts, fat cells. • WANDERING CELLS – macrophages, plasma cells, mast cells & lymphocytes Cells of Connective Tissue

16. 1. Fibroblasts: • Stem cells with multiple processes. • Spindle shaped in tissue section • Immature– FIBROBLAST • Found in all types of connective tissue. • Produce & maintain fibres & ground substance. 1. Fixed cells

18. 2. Fat cells (Adipocytes) • Specialised for synthesis & storage of fat. • Each cell shows a large globule of fat. • The nucleus is flattened pushed to the periphery. • The cytoplasm appears as a thin rim around the fat globule. • Signet ring appearance. • A group of fat cells is called Adipose tissue.

21. 1. Macrophages : • Big eater, oval in shape. • Found in the connective tissues of almost all organs of the body. • Phagocytosis - worn out RBCs ,Carbon particles. 2.Wandering cells

22. Components of loose areolar tissue as well as lymphatic tissue. • Cell is rounded but eccentrically placed nucleus. • Chromatin in the nucleus is often arranged like spokes of a wheel (cart wheel appearance). • Synthesizes and secretes Antibodies. • They develop from B lymphocytes. 2. Plasma Cells

23. Round or Ovoid in shape. • Nucleus is small and centrally placed. • Cytoplasm is packed with coarse granules. • These granules contain Histamine & Heparin. 3. Mast Cells

24. Lymphocytes – small or large rounded cells with a large darkly stained nucleus.. • Neutrophils – 3 to 5 lobes of nuclei with small or fine eosinophilic granules. 4. WBCs like Lymphocytes & Neutrophils

25. The interfibrillar substance is called ground substance or matrix. • It is made up of, Glycosaminoglycans, Proteoglycans & water. Ground Substance

26. Hyaluronic acid - Vitreous body • Chondratin - Cartilage • Dermatan - Skin • Keratan - Cornea • Heparan - Liver

27. 1. LOOSE CONNECTIVE TISSUE – • found almost everywhere in the body as a thin filling & made of fibres,cells & ground substance. Types of Ordinary Connective tissue

29. 2. DENSE CONNECTIVE TISSUE • Here the fibres are closely packed with very little matrix and cells. 2 types • Irregular & regular

30. Found in regions which experience considerable mechanical stress & where protection is needed. • Fibre bundles interweave in 3 dimensions giving it considerable strength. • Eg : Adventitia , Periosteum Dense Irregular Connective tissue

34. Forms sheets or bundles wherein the direction of arrangement of fibres is related to the stresses which they undergo. • Eg :Tendons , ligaments Dense Regular Connective tissue

37. An embryonic type of connective tissue typically seen in theWhartons jelly. • Consists of copious matrix, fine mesh of collagen & stellate cells with long processes. • In adults it is seen in the Vitreous body ofthe eye&nucleus pulposusof intervertebral disc. 2. Mucoid tissue

39. Bone • Cartilage 3. Special Connective tissue

40. Connective tissue is one of the basic tissues of the body which connects various structures. • It is mainly made up of fibres, cells & ground substance. • The composition may vary – dense, loose or mucoid. • 3 types of fibres – collagen, elastic & reticular fibres. • The connective tissue cells may be fixed or they may wander in the surrounding tissues. • Connective tissue helps in regenerations and repair of tissues. SUMMARY