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


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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：



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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.,
developed
G.l.
F.b.
* Fibrocytes:
F.C.
F.b.
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.
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
Ag
p.s
.
L.y
残余体
Capture!
Ag

participate in
immune regulation
p.s.
L.y.
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
EM：
a great number of
granules w/ crystals,
containing:
heparin,
histamine,
leukotriene,
slow-reacting
substance,
eosinophil
chemotactic factors
(ECF-A)
plasma cell
Ab(Ig E)
 Function：

allergic reactions
Ag1
Ag1
plasma cell
mast cell Ab(Ig E)
R-Ab
Ag2
degranulation


anticoagulation
attract eosinophil
Ag2
degranulation
mast cell
R
Ab-R
degranulation
Ag1
R-Ab
.
.
.. .. . ..
. . ... . .. .
. . .. . . ..
. .. . . . .. .
.. . Mast cell .
.
. ..
.
.
.. . . . .
. . . .. . . . .
.
.
.
.
.
. . .. ..
. . . .. .
. . ...
Ab
Plasma
cell
Ag2
5、Fat cells (Adipose cells)
 Shape:
Nu.:
Cytoplasm:
 Function:
synthesize
& store lipid
Osmic acid
staining
HE staining
B.V.
b
N
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:
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

Collagenous fibers （white f.）
Elastic fibers （yellow f.）
Reticular fibers
（argyrophilic f.）
1、Collagenous fibers
 Structure:
LM:
EM：
fibrils：have
periodic crossbandings at
intervals of
64nm
fibrils
Collagen fibers
Collagen fibrils

Chemicals: collagen type I
collagen type III
type I
type III
Immunohistochemistry staining
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)；
Side chain
subnit
hyaluronic
acid
Collagenous
fiber
Ground substance
Intercellular material
hyaluronic
acid
molecular sieve:
hyaluronic acid -- link
pr.-- side chain subunit
subunit: core protein
+ chondroitin sulfate &
keratin sulfate
tissue fluid: flowing
through the sieve pores
side
chain
subunit
Core pr.
link pr.
chondroitin
sulfate
Link pr.
keratin sulfate
core pr.
glycoprotein：
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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
tendons
Category:
dermis
Dense regular C.T.
(tendons, cornea, ligment):
parallel c.f. & tendon cells
Dense irregular C.T.
Lig. nuchae
(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
cells
Structure:
 Reticular cells +
reticular f. + G.S.
 Reticular cell: stellate,
pale nucleus, obvious
nucleoli, processes (rich
in rER)
Function:
architectural framework
of lymphatic & hematopoietic tissues
Lymph node
fibers
BYE
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