2. Chapter 3 Connective tissue Chapter 3 Connective tissue

3. 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

4. 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

5. 2. Classification (1) CT in narrow sense means connetive tissue proper which include: loose CTdense CT adipose Treticular tissue

6. cartilagebone blood (2) CT in wide sense includes :

7. 3. Loose connective tissue (areolar tissue) consists of cells, fiber and ground substance features: have more types of cells and less fibers

8. functions: connection, supporting, defence and repairing

9. 1)Cells:

10. 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

11. EM: rich in RER, Golgi appatatus and free ribosome ---function: synthesize fibers and ground substance

12. 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

13. fibrocyte fibroblast fibrocyte

14. ② macrophage ---structure: LM: Round, ovoid or irregular in shape have short blunt processes: pseudopodium Small and dark nucleus Acidophilic cytoplasm

16. 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

17. ---function: a. Chemotaxis: chemotactic factor b. phagocytosis: (1)Special phagocytosis: recognize bacterium, virus and foreign cell phagocytosis

18. (2)non special phagocytosis: carbon particles, dust and dead cells

19. c. secretion: lysozyme （溶菌酶）, complement and interleukin-I (IL-1)and interferon(INF) d. antigen presenting function

20. ③ plasma cell ---structure: LM: round or ovoid Nucleus with more spot-liked heterochromatin which located eccentrically Basophilic cytoplasm

21. EM: rich in parallelly arranged RER, free ribosome and Golgi complex ---function: synthesize and secrete immunoglobulin, Ig-antibody

22. ④ mast cell ---structure: LM: Round and large cell Small dark-stained nucleus Basophilic secreting granules

23. 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)

24. Cytoplasm contain: slow reaction substance ---function: to cause allergic reaction

25. 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

26. ⑥ undifferentiated mesenchymal cell ---structure: similar to fibrocyte ---function: multidifferentiating potential

27. ⑦ leukocytes: neutrophil, acidophil and lymphocyte, ect. neutrophilacidophil lymphocyte

28. 2) fibers

29. ① collagenous fiber (white fiber) LM: 1-20 um in diameter Belt-liked wave and branch to form a network Eosinophilic

31. EM: parallel-arranged fibrils Fibril: 20-200nm in diameter Have periodic cross striation at 64nm interval

32. 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）

33. ③ reticular fiber LM: thin and less,0.2-1.0 um in diameter Branch to form network Argyrophilic fiber (silver impregnation method)

34. EM: type III collagen 64nm cross striation ---distribution: reticular tissue connecting portion, e.g. reticular lamina

35. 3) ground substance ---amorphous colloidal substance ---consists of proteoglycan, glycoprotein and tissue fluid

36. 4. Dense connective tissue ---more fiber ---connection and supporting

37. 1) regular DCT: parallelly-arranged collagenous fibers tendon cells: special fibroblast wing-liked processes ---distribution: tendons, ligament and cornea

38. 2) irregular DCT: Fiber arranged in bundles, running in different direction Fibroblast less ground substance ---distribution: dermis, sclera and capsule of some organs

39. 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

41. white fat T brown fat T

42. 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