chapter 3 connective tissue
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Chapter 3 Connective tissue. 1. General features: 1) small number of cells and large amount of extracellular ground substance 2) no polarity 3) all of them originate from mesenchyme -embryonic CT - PowerPoint PPT PresentationTRANSCRIPT
Chapter 3 Chapter 3 Connective tissueConnective tissue
1. General features:
1) small number of cells and large amount of extracellular ground substance
2) no polarity
3) all of them originate from mesenchyme -embryonic CT
4) have functions of connection, supporting, protecting, nutrition, defence and repairing
mesenchyme---mesenchymal cell: structure:• stellate in shaped with proc
esses• 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 (1) CT in narrow sense means connetive
tissue proper which include:
loose CT dense CTadipose T reticular tissue
cartilage bone
blood
(2) CT in wide sense includes (2) CT in wide sense includes ::
3. Loose connective tissue (areolar tissue)
• consists of cells, fiber and ground substance
features: have more types of cells and less fibers
functions:functions: connection, supporting, d connection, supporting, defence and repairingefence and repairing
1)1) Cells:Cells:
① fibroblast
---structure: LM: • large,flattened cell with processes- stellate in
shaped• Large ovoid pale nucleus - contain more fine
chromatin, with clear one or two nucleoli• Weakly basophilic cytoplasm
EM:• rich in RER, Golgi appatatus and free ribosome
---function: synthesize fibers and ground substance
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
fibrocyte
fibroblast fibroblast fibrocyte
②macrophage---structure:
LM:• Round, ovoid or irregular in shape• have short blunt processes: pseudopodium• Small and dark nucleus• Acidophilic cytoplasm
EM: rich in
• a. Lysosome(溶酶体)• b. Phagosome: phagocytosis(吞饮作用)• pinosome(吞饮体) : pinocytosis(胞饮作用 )
• c. Remnant• d. Microfilament and microtubule
---function:
a. Chemotaxis: chemotactic factor
b. phagocytosis:
(1)Special phagocytosis: recognize bacteri
um, virus and foreign cell
phagocytosis
(2)non special(2)non special phagocytosis:phagocytosis: carbon par carbon particles, dust and dead cellsticles, dust and dead cells
c. secretion: lysozyme(溶菌酶) , com
plement and interleukin-I (IL-1)and interf
eron(INF)
d. antigen presenting function
③plasma cell
---structure:
LM:• round or ovoid• Nucleus with more spot-liked heterochromatin
which located eccentrically• Basophilic 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 edema and contraction of SM
• Eosinophil chemotactic factor
(chemotactic factor:
macrophage, leukocytes)
Cytoplasm contain:
• slow reaction substance
---function: to 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 fibrocyte
---function: multidifferentiating potential
• ⑦leukocytes: neutrophil, acidophil and lymphocyte, ect.
neutrophil acidophil lymphocyte
2) fibers2) fibers
①collagenous fiber (white fiber)
LM: • 1-20 um in diameter• Belt-liked wave and branch to form a network• Eosinophilic
EM: parallel-arranged fibrilsFibril: • 20-200nm in diameter• Have periodic cross striation at 64nm interval
② elastic fiber (yellow fiber) 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 10-12 nm, electron dense ↑ fibrillin(微纤维蛋白)
③reticular fiberLM: • 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
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, running in different
direction• Fibroblast• less ground substance---distribution: dermis, sclera and capsule of
some organs
5. adipose tissue---LCT+fat cells---white fat T: • single fat cell• distribution in subcutaneous tissue, mesenteriu
m---brown fat T: • fat cell contain many small lipid droplets,• rich in large mitochondria• centrally-located nucleus• rich in cap.• distribution: neonate
white fat Tbrown fat T
6. reticular tissue---reticular cells: • stellate with processes-form network• round, ovoid and pale nucleus with 1-2 nucle
oli• EM: rich in RER---reticular fiber: connect to form network---distribution: hemopoietic tissue and lymphatic
tissue