Chapter 3
Connective tissue
1,General features:
1) small number of cells and large amount of
extracellular ground substance
2) extracellular is composed of fibers and
amorphous ground substance-matrix
3) all of them originate from mesenchyme-
embryonal CT
4) have functions of connection,supporting,
protecting,nutrition,defence and repairing
mesenchyme
---mesenchymal cell:
/structure:
stellate in shaped with
processes
a large nucleus,with clear
nucleoles
slight basophilic cytoplasm
/function:
a,undifferentiated cell
b,multiple developmental
potential→CT cell,SM and
endothelial cell
---matrix
2,Classification
---CT in narrow sense means connetive
proper which include loose CT,dense CT,
adipose T and reticular tissue
---CT in wide sense includes cartilage,bone
and blood
3,Loose connective tissue(areolar
tissue)
features,have more types of cells and less
fibers
functions,connection,supporting,defence and
repairing
consists of cells,fiber and ground substance
1) cells:
seven types of cells are present in LCT
① fibroblast
---structure:
LM:
large,flattened cell with processes- stellate in
shaped
Large ovoid pale nucleus-contain more fine
chromatin,with clear one-two nucleoli
Weakly basophilic cytoplasm-homogeneous
EM:
rich in RER,Golgi appatatus and free
ribosome
---function,synthesize fibers and ground
substance
Synthesis of
collagenous fiber
Three steps:
a.synthesis of
procollagen(RER) →
process(Golgi) → out
of cell
b.procollagen→
tropocollagen → fibril
c.fibril →
collagenous fiber
*fibrocyte,still state or inactive fibroblast
---structure:
spindle-shaped,small
N:small,dark stained
Acidophilic cytoplasma
EM,less organelles
---function,become into fibroblast for repairing
② macrophage
---structure:
LM:
round or ovoid-irregular in shape when it
have short blunt processes_pseudopodium
Small and dark nucleus
Acidophilic cytoplasm
EM,rich in
a,lysosome
b,Phagosome← phagocytosis and
pinosome ←pinocytosis
c,Remnant
d,Microfilament and microtubule
---function:
a,Chemotaxis,chemotactic factor
b,phagocytosis:
Special phagocytosis,recognize Bacterium,
virus and foreign cell
non special,carbon particles,dust and dead
cells
*Phagosome(pinosome) + primary lysosome
→secondary lysosome →remnants
c,secretion,lysozyme,complement and
interleukin-I (IL-1)and interferon(INF)
b,antigen presenting function:
*capture antigen→processes→+ MHC II
molecule (major histocompatibility
complex molecules) →antigen-MHC II
complexes→TLC
③ plasma cell
---structure:
LM:
round or ovoid
Round eccentrically-located nucleus with
more spot-liked heterochromatin
Basophilic cytoplasm
EM,rich in parallelly arranged RER,free
ribosome and Golgi complex
---function,synthesize and secrete
immunoglobulin,Ig-antibody
④ mast cell
---structure:
LM:
round and large cell
Small dark-stained nucleus
Basophilic secreting granules
Basophilic secreting granules:
heparin:an anticoagulant
Histamine,cause cap,permeability↑,cap.
leakage to form oedema and contraction of SM
Eosinophil chemotactic factor
Cytoplasm contain:
leukotriene- slow reaction
substance
---function,cause allergic
reaction
⑤ fat cell
---structure:
large,round or polygonal
flattened ovoid nucleus located on one side of
cell
thin layer of cytoplasm
a large lipid droplet
---function,synthesize and store fat
⑥ undifferentiated mesenchymal cell
---structure:similar to fibrocyto
---function:multidifferentiating potential
⑦ leukocytes,neutrophil,acidophil and
lymphocyte
2) fibers
① collagenous fiber(white fiber)
LM:
1-20 um in diameter
Belt-liked wave and branch to form a network
Eosinophilic
EM,parallel-arranged fibrils
Fibril:
20-200nm in diameter
Have periodic cross striation at 64nm interval
*formation,Extracellular polymerize
collagen(type I and III) →collagenous fibril → collagenous
fiber
② elastic fiber (yellow fiber)
LM:
thinner and less,0.2-1.0 um
Slight red(HE),purple(aldehyde fuchsin) or
brown(orcein)
Branch and form a network
EM:
core,elastin-low electron density
Peripheral,microfibril 10-12 nm,electron dense
↑
fibrillin
③ reticular fiber
LM:
thin and less,0.2-1.0 um in diameter
Branch to form network
Argyrophilic fiber(silver impregnation method)
EM:
type III collagen
64nm cross striation
---distribution:
reticular tissue
connecting portion,e.g.reticular lamina
3) ground substance
---amorphous colloidal substance
---consists of proteoglycan,glycoprotein
and tissue fluid
① proteoglycan-large
molecular complex
---glycosaminoglycans:
chondroitin sulfate
keratin sulfate
dermatan sulfate
heparin sulfate
hyaluronic acid,2.5um
long
--protein
*molecular sieve
② glycoprotein,proteins
---fibronectin
cells←fibronectin→collagen
↓
proteoglycan
---laminin
---chondronectin
---function:
Connection
affect the differentiation and movement of
cells
③ tissue fluid
tissue
artery → Tissue fluid → vein →blood steam
cells
dehydration
oedema
4,Dense connective tissue
---more fiber
---connection and supporting
1) regular DCT:
parallelly-arranged collagenous fibers
tendon cells,/special fibroblast
/wing-liked processes
---distribution,tendons,ligament and cornea
2) irregular DCT:
Fiber arranged in bundles,runing in different
direction
Fibroblast
less ground substance
---distribution,dermis,sclera and capsule of
some organs
3) elastic T:
elastic fiber in bundles or in membrane
ligament and large artery
5,adipose tissue
---LCT+fat cells
---white fat T:
single fat cell
distribution in subcutaneous tissue,
mesenterium
---brown fat T:
fat cell contain many small lipid droplets,
rich in large mitochondria
centrally-located nucleus
rich in cap.
distribution,neonate
6,reticular tissue
---reticular cells:
stellate with processes-form network
round,ovoid and pale nucleus with 1-2
nucleoli
EM,rich in RER
---reticular fiber,connect to form network
---distribution,hemopoietic tissue and lymphatic
tissue
Connective tissue
1,General features:
1) small number of cells and large amount of
extracellular ground substance
2) extracellular is composed of fibers and
amorphous ground substance-matrix
3) all of them originate from mesenchyme-
embryonal CT
4) have functions of connection,supporting,
protecting,nutrition,defence and repairing
mesenchyme
---mesenchymal cell:
/structure:
stellate in shaped with
processes
a large nucleus,with clear
nucleoles
slight basophilic cytoplasm
/function:
a,undifferentiated cell
b,multiple developmental
potential→CT cell,SM and
endothelial cell
---matrix
2,Classification
---CT in narrow sense means connetive
proper which include loose CT,dense CT,
adipose T and reticular tissue
---CT in wide sense includes cartilage,bone
and blood
3,Loose connective tissue(areolar
tissue)
features,have more types of cells and less
fibers
functions,connection,supporting,defence and
repairing
consists of cells,fiber and ground substance
1) cells:
seven types of cells are present in LCT
① fibroblast
---structure:
LM:
large,flattened cell with processes- stellate in
shaped
Large ovoid pale nucleus-contain more fine
chromatin,with clear one-two nucleoli
Weakly basophilic cytoplasm-homogeneous
EM:
rich in RER,Golgi appatatus and free
ribosome
---function,synthesize fibers and ground
substance
Synthesis of
collagenous fiber
Three steps:
a.synthesis of
procollagen(RER) →
process(Golgi) → out
of cell
b.procollagen→
tropocollagen → fibril
c.fibril →
collagenous fiber
*fibrocyte,still state or inactive fibroblast
---structure:
spindle-shaped,small
N:small,dark stained
Acidophilic cytoplasma
EM,less organelles
---function,become into fibroblast for repairing
② macrophage
---structure:
LM:
round or ovoid-irregular in shape when it
have short blunt processes_pseudopodium
Small and dark nucleus
Acidophilic cytoplasm
EM,rich in
a,lysosome
b,Phagosome← phagocytosis and
pinosome ←pinocytosis
c,Remnant
d,Microfilament and microtubule
---function:
a,Chemotaxis,chemotactic factor
b,phagocytosis:
Special phagocytosis,recognize Bacterium,
virus and foreign cell
non special,carbon particles,dust and dead
cells
*Phagosome(pinosome) + primary lysosome
→secondary lysosome →remnants
c,secretion,lysozyme,complement and
interleukin-I (IL-1)and interferon(INF)
b,antigen presenting function:
*capture antigen→processes→+ MHC II
molecule (major histocompatibility
complex molecules) →antigen-MHC II
complexes→TLC
③ plasma cell
---structure:
LM:
round or ovoid
Round eccentrically-located nucleus with
more spot-liked heterochromatin
Basophilic cytoplasm
EM,rich in parallelly arranged RER,free
ribosome and Golgi complex
---function,synthesize and secrete
immunoglobulin,Ig-antibody
④ mast cell
---structure:
LM:
round and large cell
Small dark-stained nucleus
Basophilic secreting granules
Basophilic secreting granules:
heparin:an anticoagulant
Histamine,cause cap,permeability↑,cap.
leakage to form oedema and contraction of SM
Eosinophil chemotactic factor
Cytoplasm contain:
leukotriene- slow reaction
substance
---function,cause allergic
reaction
⑤ fat cell
---structure:
large,round or polygonal
flattened ovoid nucleus located on one side of
cell
thin layer of cytoplasm
a large lipid droplet
---function,synthesize and store fat
⑥ undifferentiated mesenchymal cell
---structure:similar to fibrocyto
---function:multidifferentiating potential
⑦ leukocytes,neutrophil,acidophil and
lymphocyte
2) fibers
① collagenous fiber(white fiber)
LM:
1-20 um in diameter
Belt-liked wave and branch to form a network
Eosinophilic
EM,parallel-arranged fibrils
Fibril:
20-200nm in diameter
Have periodic cross striation at 64nm interval
*formation,Extracellular polymerize
collagen(type I and III) →collagenous fibril → collagenous
fiber
② elastic fiber (yellow fiber)
LM:
thinner and less,0.2-1.0 um
Slight red(HE),purple(aldehyde fuchsin) or
brown(orcein)
Branch and form a network
EM:
core,elastin-low electron density
Peripheral,microfibril 10-12 nm,electron dense
↑
fibrillin
③ reticular fiber
LM:
thin and less,0.2-1.0 um in diameter
Branch to form network
Argyrophilic fiber(silver impregnation method)
EM:
type III collagen
64nm cross striation
---distribution:
reticular tissue
connecting portion,e.g.reticular lamina
3) ground substance
---amorphous colloidal substance
---consists of proteoglycan,glycoprotein
and tissue fluid
① proteoglycan-large
molecular complex
---glycosaminoglycans:
chondroitin sulfate
keratin sulfate
dermatan sulfate
heparin sulfate
hyaluronic acid,2.5um
long
--protein
*molecular sieve
② glycoprotein,proteins
---fibronectin
cells←fibronectin→collagen
↓
proteoglycan
---laminin
---chondronectin
---function:
Connection
affect the differentiation and movement of
cells
③ tissue fluid
tissue
artery → Tissue fluid → vein →blood steam
cells
dehydration
oedema
4,Dense connective tissue
---more fiber
---connection and supporting
1) regular DCT:
parallelly-arranged collagenous fibers
tendon cells,/special fibroblast
/wing-liked processes
---distribution,tendons,ligament and cornea
2) irregular DCT:
Fiber arranged in bundles,runing in different
direction
Fibroblast
less ground substance
---distribution,dermis,sclera and capsule of
some organs
3) elastic T:
elastic fiber in bundles or in membrane
ligament and large artery
5,adipose tissue
---LCT+fat cells
---white fat T:
single fat cell
distribution in subcutaneous tissue,
mesenterium
---brown fat T:
fat cell contain many small lipid droplets,
rich in large mitochondria
centrally-located nucleus
rich in cap.
distribution,neonate
6,reticular tissue
---reticular cells:
stellate with processes-form network
round,ovoid and pale nucleus with 1-2
nucleoli
EM,rich in RER
---reticular fiber,connect to form network
---distribution,hemopoietic tissue and lymphatic
tissue
