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

Structure: Nu: Cytoplasm: EM ： rich in rER & r., developed G.l.

1 、 FibroblastsF.b.

* Fibrocytes:

Function ： Synthesize & secrete collagenous pro.

& elastic pro. （ to form collagenous f., elastic f. & reticular f. ） ; and ground substance (proteoglycan & glycoprotein).

F.b.F.C.

3 、 Plasma cells

Structure:

Nu.:eccentrically， heterochromatin in wheel shape

Cytoplasm: strong basophilic w/ lightly-stained area near Nu.

P.C.

EM ： rich in rER & r.,

developed Gl. Source: B lmphocytes Function: synthesize immunoglobulin

& cellular factors participate in humoral

immunity

2 、 Macrophages （ Histocytes ）

Structure:

Nu.: Cytoplasm:

Mac.

F.b.

Mac.

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

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!

participate in immune regulation

capture process antigen present antigen presenting

molecular:MHCII

Ag-MHCII co. macrophage surface lymphocytes immune reaction

L.y.

p.s.

Ag

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

B.V.

M.C.

4 、 Mast cells Location & Structure: Nu.: Cytoplasm: basophilic

granules, metachromatism

Toluiding blue staining

EM ： a great number of

granules w/ crystals, containing: heparin, histamine, leukotriene, slow-reacting substance, eosinophil chemotactic

factors (ECF-A)

Function ： allergic reactions

Ag1 plasma cell

mast cell Ab(Ig E)

R-AbAg2 degranulation anticoagulation attract eosinophil

Ag1

Ag2Ab-R

R

degranulation mast cell

plasma cell Ab(Ig E)

degranulation

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Mast cell

R-Ab

Ag2

Ag1

Plasma cell

Ab

5、 Fat cells (Adipose cells)

Shape: Nu.: Cytoplasm: Function: synthesize & store lipid

bN

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)

LN

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

1 、 Collagenous fibers Structure: LM: EM ： fibrils ：

have periodic cross-bandings at intervals of 64nm

fibrils

Collagen fibrils

Collagen fibers

Chemicals: collagen type I collagen type III

type I type III

Immunohistochemistry staining

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

Fibroblast

280x1.4nm

①

②

③

④

⑤

⑥

2 、 Elastic fibers

Structure: LM: EM ： elastin + microfibrils

(no bandings)

F.B.

3 、 Reticular fibersSructure: LM: argyrophilia, PAS(+) EM: fibrils w/

periodiccross-bandings atintervals of 64nm, typeIII collagencovered carbohydrate

Reticular fibersin liver

Reticular fibersin 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) ；

Intercellular material

Ground substance

Collagenous fiber

hyaluronic acid

Side chain subnit

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.

side chain subunit

hyaluronicacid

link pr.

core pr.

chondroitin sulfate

keratin sulfate

Link 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): 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

dermis

tendons

Lig. nuchae

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

frameworkof lymphatic & hemato-poietic tissues

Lymph node

cells

fibers

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