Upload
fritz-moran
View
54
Download
5
Tags:
Embed Size (px)
DESCRIPTION
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 - PowerPoint PPT Presentation
Citation preview
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 pot
ential→CT cell, SM and endothelial cell
---matrix
2. Classification ---CT in narrow sense means connetive prop
er 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 shapedLarge ovoid pale nucleus-contain more fine chromatin, with clear one-two nucleoliWeakly 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 procol
lagen(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
②macrophage---structure:
LM:round or ovoid-irregular in shape when it have short blunt processes_pseudopodiumSmall and dark nucleusAcidophilic cytoplasm
EM: rich in a. lysosomeb. Phagosome← phagocytosis and pinosome ←pinocytosisc. Remnantd. 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
③plasma cell---structure:
LM:round or ovoidRound eccentrically-located nucleus with more spot-liked heterochromatinBasophilic cytoplasm
EM: rich in parallelly arranged RER, free ribosome and Golgi complex
---function: synthesize and secrete immunoglobulin, Ig-antibody
④mast 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
⑤fat 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
⑥undifferentiated mesenchymal cell
---structure:similar to fibrocyto
---function:multidifferentiating potential
⑦leukocytes: neutrophil,acidophil and lymphocyte
2) fibers
①collagenous fiber(white fiber)
LM: 1-20 um in diameterBelt-liked wave and branch to form a networkEosinophilic
EM: parallel-arranged fibrilsFibril:
20-200nm in diameterHave 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 umSlight red(HE), purple(aldehyde fuchsin) or brown(orcein)Branch and form a network
EM: core: elastin-low electron densityPeripheral: microfibril 10-12 nm, electron dense
↑ fibrillin
③reticular fiberLM:
thin and less,0.2-1.0 um in diameterBranch to form networkArgyrophilic fiber(silver impregnation method)
EM: type III collagen64nm cross striation
---distribution: reticular tissueconnecting portion, e.g.reticular lamina
3) ground substance
---amorphous colloidal substance
---consists of proteoglycan, glycoprotein and tissue fluid
①proteoglycan-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:
Connectionaffect 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 directionFibroblastless 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 celldistribution in subcutaneous tissue, mesenterium
---brown fat T: fat cell contain many small lipid droplets,rich in large mitochondriacentrally-located nucleusrich in cap.distribution: neonate
6. reticular tissue---reticular cells:
stellate with processes-form networkround, ovoid and pale nucleus with 1-2 nucleoliEM: rich in RER
---reticular fiber: connect to form network---distribution: hemopoietic tissue and lymphatic
tissue