Connective tissue Jun Zhou ( 周周 ) School of Medicine, Zhejiang University 20140408
Connective tissue
Jun Zhou ( 周俊 )School of Medicine, Zhejiang University
20140408
General features small number of cells and large amount of
extracellular ground substance no polarity vascularized originate from mesenchyme (间充质) -embryonic
CT Function: connection, supporting, protecting,
nutrition, defence and repairing
Mesenchyme ( 间 充质)
---mesenchymal cell: Structure: stellate in shaped with processes a large nucleus,with clear nucleolus slight basophilic cytoplasm
Function: undifferentiated cell multiple developmental potential
→CT cell, SM and endothelial cell
---matrix
Classification ---CT in narrow sense means connetive
tissue proper ( 固 有 结 缔 组 织 ) which include loose CT, dense CT, adipose T and reticular tissue
---CT in wide sense includes cartilage( 软骨 ),
bone and blood
cartilage bone
blood
Features: more types of cells, less fibers Functions: connection, supporting, defence and
repairing consists of cells, fiber and ground substance
Loose connective tissue (疏松结缔组织) (areolar tissue)
Fibers
1. Collagenous fibers (胶原纤维)
2. Elastic fibers (弹性纤维)
3. Reticular fibers (网状纤维)
LM: 1-20 um in diameter Belt-liked wave and branch to form a network Eosinophilic
Collagenous fiber (胶原纤维) (white fiber)
EM: parallel-arranged fibrilsFibril (原纤维) : 20-200nm in diameterHave periodic cross striation at 64-70nm
interval
LM: thinner and less, 0.2-1.0 um Slight red (HE) branch and form a network EM: core: elastin-low electron density Peripheral: microfibril ( 微原纤维 )10-12 nm, electron dense ↑ fibrillin( 原纤维蛋白 )
Elastic fiber (弹性纤维)(yellow 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 striationDistribution: reticular tissue connecting portion, e.g.reticular lamina
Reticular fiber (网状纤维)
Ground substance (基质)---amorphous colloidal substance
---consists of proteoglycan (蛋白多糖) , glycoprotein(糖蛋白) and tissue fluid
①Proteoglycan ( 蛋 白 多 糖 ) -large molecular complex
---glycosaminoglycans (糖胺多糖)chondroitin sulfate (硫酸软骨素)keratin sulfate (硫酸角质素)heparan sulfate (硫酸乙酰肝素)hyaluronic acid ( 透 明 质 酸 ) :
2.5um long--protein
*molecular sieve ( 分子筛 )
② Glycoprotein (糖蛋白) : proteins---fibronectin ( 纤维粘连蛋白 )---laminin ( 层粘连蛋白 )---chondronectin ( 软骨粘连蛋白 )
---Function: Connection affect the differentiation and movement of
cells
③ tissue fluid (组织液) tissue artery → Tissue fluid → vein (lymphatic vessel)
cellsDehydration (脱水)Edema (水肿)
Molecular sieve ( 分子筛 )
Function:
1.Provides mechanical and structural support for metabolism
2.Influences extracellular communication
3.Limitation of inflammation
Cells
ResidentFibroblasts (Fibrocytes) (成纤维细胞) Macrophages (Histiocytes) (巨噬细胞)Plasma cells (浆细胞)Mast cells (肥大细胞) Adipocytes (脂肪细胞)Stem Cells (干细胞) (committed but not differentiated)
TransientNucleated Blood Cells (Lymphocytes,
Plasma Cells, Eosinophils- others occasionally)
---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
Fibroblast(成纤维细胞)
EM: rich in RER, Golgi apparatus and free ribosome
Function: synthesize fibers and ground substance
Three steps:
a.synthesis of procollagen (RER) → process(Golgi) → out of cell
b.procollagen→ tropocollagen → fibril
c.fibril → collagenous fiber
Synthesis of collagenous fiber
( 前胶原蛋白 )
( 原胶原蛋白 )
( 胶原原纤维 )
Fibrocyte ( 纤维细胞 ):
inactive fibroblast
---Structure: spindle-shaped, smallN:small,dark stained Acidophilic cytoplasmaEM: less organelles
---Function:: become into fibroblast for repairing
From monocytes---Structure:LM: round or ovoid-irregular in shape , short blunt
processes pseudopodium( 伪足 )Small and dark nucleusAcidophilic cytoplasm
Macrophage ( 巨噬细胞 )
EM: rich in Lysosome (primary, secondary) Phagosome( 吞噬体 )← phagocytosis and pinosome ( 吞饮小泡 )←pinocytosis Remnant Microfilament and microtubule Mitochondria
---Function: Chemotaxis: chemotactic factor Phagocytosis:1) Special phagocytosis: recognize bacterium, virus and
foreign cell2) non special: carbon particles, dust and dead cells Secretion: lysozyme, complement and interleukin-I
(IL-1)and interferon(IFN) Antigen presenting function
Mature B lymphocyte---structure: LM: round or ovoidRound eccentrically-located nucleus with more spot-
liked heterochromatinBasophilic cytoplasm
Plasma cell ( 浆 细胞)
EM: RER, free ribosome and Golgi complex
Function: synthesize and secrete immunoglobulin,
Ig-antibody
---structure:
LM: round and large cellSmall dark-stained nucleusBasophilic secreting granules
Metachromatic 异染性
Mast cell ( 肥 大 细胞)
Basophilic secreting granules: heparin: an anticoagulant Histamine: cause cap. permeability↑, cap. leakage to
form edema and contraction of SM Eosinophil chemotactic factor
Cytoplasm contain: slow reaction substance
--Function: involved in allergic reaction
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
Mesenchymal cell similar to fibrocyte multidifferentiating potential
Leukocytes: neutrophil, acidophil and
lymphocyte
Dense connective tissue
(致密结缔组织)---more fiber
---connection and supporting
1) Regular DCT: parallelly-arranged collagenous fibers special fibroblast
wing-liked processes
---Distribution: tendons, ligament, cornea
2) Irregular DCT: Fiber arranged in bundles, running in different
direction Fibroblast less ground substance
---Distribution: dermis, sclera,capsule of some organs
Adipose tissue (脂肪组织)---LCT+fat cells---White fat T: single fat cellDistribution: subcutaneous tissue, mesenterium---Brown fat T: fat cell contain many small lipid droplets, rich in large mitochondriacentrally-located nucleus rich in cap.Distribution: newborn baby
Reticular tissue (网状组织)---Reticular cells + Reticular fiber + Stroma ---Reticular cells: Irregular 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
THE END!