Download Connective tissue

Connective Tissue
1. General characteristics
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Features: 1. Small number cells and a large
amount of matrix 2. No polarity and filled
with blood and vessels
Distribution: widely in the body
Function: connection, support, nutrition
transportation and protection
Origin:
Mesenchyme
mesenchymal cells, matrix and no fibers
Connective tissue:
Connective tissue proper
 Blood
 Cartilage
 Bone
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Connective tissue proper:
Loose connective tissue
 Dense connective tissue
 Adipose tissue
 Reticular tissue
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2. Loose connective tissue
(areolar tissue)
structural features: (1)a great variety of
cell. (2)small number fibers
 distribution: widely among organs and
tissues.
 function: connection and support,
defense and repair
 components:
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components:
(1) intercellular substances:
fibers
ground substance
 (2) cells:
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2.1 Fibers
collagenous fibers
 reticular fibers
 elastic fibers
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2.1.1 collagenous fibers
Structure
 LM section stretch
Collagenous fibril
 EM Collagenous fibril: collagenous
fibril with periodic cross striation
 Chemical component:
collagen (type Ⅰ, Ⅲ )
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2.1.2 reticular fibers
 Stucture:
LM EM
 Distribution:terminal web
 Chemical component
collegen (type Ⅲ )
argyrophil fibers
2.1.3 elastic fibers
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Stucture
 LM
 EM
 elastin in the core
 microfibril in periphery
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Function: keep organs position and shape
2.2
ground substance
Proteoglycan
Glycoprotein
Tissue
fluid
2.2.1 proteoglycan
 glycosaminoglycan:
hyaluronic acid
chondroitin sulfate A,C
keratin sulfate
heparan sulfate
 Function
molecular sieve
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2.2.2 glycoprotein:
fibronectin
laminin
chondronnectin
2.2.3 tissue fluid
The plasma is filtered out
capillary to form tissue fluid
2.3 cells
fibroblasts
 fat cells
 undifferentiated mesenchymal cells
 macrophages
 plasma cells
 mast cells
 white blood cells
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2.3.1 fibroblasts, fibrocytes
 Structure
LM stellate, weekly
basophillic. Nucleus appears
ovoid, pale and clear
nucliolus
EM
 Function: production of fibers
and matrix
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2.3.2 fat cells
 Structure
 Function:
energy reservoir,
shock-absorbent padding and
insulating layer of body heat.
2.3.3 undifferentiated
mesenchymal cells
 Structure
 Function:
differentiate into
various connective tissue celltypes
2.3.4 macrophages
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Types
 Histocytes: fixed in loose connective tissue
 wandering macrophages: wandering to
inflammation area
Structure
 LM: phagosome
 EM: lysosome
Origin:
Function：phagocytosis, antigen presenting
and secreting lysozyme and complement
Function of Macrophages
Chemotaxis, chemotactic factor
 Phagocytosis
 Secretion: lysozyme, interferon,
complement.
 Immune reaction(response):
 antigen-presenting cells, APC
 immune effect cells
 immune regulation: cytokines
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2.3.5
plasma cells
 Distribution:
digestive tract,
respiratory tract
 Structure
LM:the nucleus is wheel-like
EM: rough endoplasmic
reticulum
 Origin: from B lymphocyte
 Function: secrete immunoglobin
2.3.6 mast cells
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distribution：along the small blood vessels
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structure
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LM: metachromatic granules in cytoplasm
EM：lysosome and secretory granules
origin
function: allergic reaction and
degranulation
 heparin ------ anticoagulant
 histamin ----allergy
 leukotriene----allergy
2.3.7 white blood cells
3. dense connective tissue
 1)
dense irregular connective tissue
 2) dense regular connective tissue
 3) elastic tissue
4. adipose tissue
White (yellow) adipose tissue
fat cell appears ring-like: a single large
droplet in the cytoplasm, and the
flattened nucleus locates the rim
 Brown adipose tissue
rich of vessel in the tissue. Several small
droplets in the cytoplasm, and the
nucleus locates in the center
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5. reticular tissue
 reticular
cells
look stellate and form the web
with other cells
 reticular fibers
tree-like and form the web
 ground substances