CONNECTIVE TISSUE PROPER

Epithelium Connective tissue Pay attention to the differences b/w Epi & CT

一、CHARACTERISTICS： Small number of cell large amount of intercellular matrix Cell: separate and no polarity Intercellular matrix: fibers + ground substance + tissue fluid Filled with B.V., L.V., & N. Function: support, connect, nourish, defence, and repair etc.

二、CLASSIFICATION Connective tissue proper: Loose C.T. Dense C.T. Adipose tissue Reticular tissue Cartilage and bone Blood and Lymph

三、LOOSE CONNECTIVE TISSUE I. Characteristics： Small number of cell & large number of cell category small number of fibers & great amount of ground substance Sponge-like structure (areolar tissue) Distributed b/w cells, tissues and organs.

II. Cells Fixed cells: fibroblasts fat cells undifferentiated mesenchymal cells Wandering cells: macrophages plasma cells mast cells leukocytes

1、Fibroblasts Structure: Nu: Cytoplasm: EM： rich in rER & r., F.b. Structure: Nu: Cytoplasm: EM： rich in rER & r., developed G.l.

* Fibrocytes: Function： F.b. F.C. Function： Synthesize & secrete collagenous pro. & elastic pro. （to form collagenous f., elastic f. & reticular f. ）; and ground substance (proteoglycan & glycoprotein).

3、Plasma cells Structure: Nu.:eccentrically，heterochromatin in wheel shape Cytoplasm: strong basophilic w/ lightly-stained area near Nu. P.C.

immunoglobulin & cellular factors participate in humoral immunity EM：rich in rER & r., developed Gl. Source: B lmphocytes Function: synthesize immunoglobulin & cellular factors participate in humoral immunity

2、Macrophages（Histocytes） F.b. Structure: Nu.: Cytoplasm:

EM：a large number of Ly., pinosome & phagosomes, bundles of MT & MF

bacterial products etc. Phagocytize Function: Mobility chemotaxis chemotactic factor: complement C5a, bacterial products etc. Phagocytize specific:depend on identify factors: Ab, C, Fibronectin etc （the receptors of these factors are on surface of the macrophage）. non-specific: independently L.y p.s. Ag 残余体

Capture!

antigen presenting molecular:MHCII Ag-MHCII co. macrophage surface L.y. p.s. Ag participate in immune regulation capture process antigen present antigen presenting molecular:MHCII Ag-MHCII co. macrophage surface lymphocytes immune reaction

secrete bioactive products chemotactic factor（for polymorphonuclear leukocytes） immunosuppressive factor leukotriene interleukin(IL) interferon(INF) tumorous necrosis factor(TNF) etc. Source： the monocytes in blood

4、Mast cells Location & Structure: Nu.: Cytoplasm: basophilic granules, metachromatism M.C. B.V. Toluiding blue staining

a great number of granules w/ crystals, containing: heparin, EM： a great number of granules w/ crystals, containing: heparin, histamine, leukotriene, slow-reacting substance, eosinophil chemotactic factors (ECF-A)

Function： allergic reactions anticoagulation attract eosinophil Ab-R R degranulation plasma cell Ab(Ig E) Function： allergic reactions Ag1 plasma cell mast cell Ab(Ig E) R-Ab Ag2 degranulation anticoagulation attract eosinophil mast cell

degranulation

Ag1 Plasma cell Ab . R-Ab . . . Mast cell Ag2

5、Fat cells (Adipose cells) Shape: Nu.: Cytoplasm: Function: synthesize & store lipid b N B.V. Osmic acid staining HE staining

6、Undifferentiated cells Structure: similar to fibroblasts, smaller Function: differentiate into various cell-types in C.T. during injury repairing e.g.:

7、Leukocytes Including: neutrophils, eosinophils, lymphocytes & monocytes Function: defence involve in allergic reaction (see blood chapter) L N

III. Fibers: Elastic fibers （yellow f.） Reticular fibers Collagenous fibers （white f.） Elastic fibers （yellow f.） Reticular fibers （argyrophilic f.）

1、Collagenous fibers Structure: LM: fibrils EM： fibrils：have periodic cross-bandings at intervals of 64nm fibrils

Collagen fibrils Collagen fibers

Immunohistochemistry staining Chemicals: collagen type I collagen type III type I type III Immunohistochemistry staining

In Extracellular space: → Tropocollagen ④ → fibrils ⑤ ① Fibroblast Synthesize: In rER ／ GL: → Polypeptide 　 　　αchains ① → hydroxylated αchains ② → Procollagen ③ In Extracellular space: → Tropocollagen ④ → fibrils ⑤ → collagenous f. ⑥ ② ③ ④ 280x1.4nm ⑤ ⑥

2、Elastic fibers Structure: LM: EM： elastin + microfibrils (no bandings) F.B.

3、Reticular fibers Sructure: LM: argyrophilia, PAS(+) EM: fibrils w/ periodic cross-bandings at intervals of 64nm, typeIII collagen covered carbohydrate

Reticular fibers in liver Reticular fibers in lymph node

IV. Ground substance Jelly-like & amorphous substance; Proteoglycan: in molecular sieve hyaluronic acid GAG(glycosaminoglycan) chondroitin sulfate keratin sulfate etc. protein: core protein & link protein glycoprotein： fibronectin (FN) laminin (LN) chondronectin (ChN)；

Ground substance Side chain subnit hyaluronic acid Collagenous fiber Intercellular material Ground substance Collagenous fiber hyaluronic acid Side chain subnit

hyaluronic acid -- link pr.-- side chain subunit subunit: core protein chondroitin sulfate keratin sulfate Link pr. molecular sieve: hyaluronic acid -- link pr.-- side chain subunit subunit: core protein + chondroitin sulfate & keratin sulfate tissue fluid: flowing through the sieve pores Core pr.

glycoprotein： fibronectin (FN): produced by epithelial cells and fibroblasts play a role in events of identification, adhesion, migration and proliferation laminin (LN) : located in B.M., produced by epi. cells, function: adhesion the epi.cells and B.M. chondronectin (ChN): in cartilage tissue, fuction: a component of ground substances; adhesion chondrocyteS and colagen typeII

leminin

Function: Tissue fluid nourishes the cells & tissues； Molecular sieve acts as a barrier: to prevent the spread of bacteria & other microorganisms *haemolytic streptococci produce hyaluronidase & promote the invasion Glycoproteins (FN/LN/ChN): identification /adherence/migration/proliferation etc.

四、 DENSE CONNECTIVE TISSUE Characteristics: Small amount of cells & ground substance， large number of fibers Fibers: wide, arranged densely Function: connect & support

Category: Dense regular C.T. (tendons, cornea, ligment): dermis tendons Lig. nuchae Category: Dense regular C.T. (tendons, cornea, ligment): parallel c.f. & tendon cells Dense irregular C.T. (dermis, sclera): collagenous fibers network & fibroblasts Elastic tissue (Lig. Nuchae, Lig. flavum & Large artery ): elastic fibers mainly Large artery

五、ADIPOSE TISSUE Structure: Loose C.T.+ fat cells (in large aggregations) HE: / Osmic acid: Function: energy storage, shock absorber, insulating layer

六、RETICULAR TISSUE Structure: Reticular cells + reticular f. + G.S. Reticular cell: stellate, pale nucleus, obvious nucleoli, processes (rich in rER) Function: architectural framework of lymphatic & hemato- poietic tissues Lymph node fibers

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