Connective Tissue

1. Connective Tissue

2. 1. General characteristics • 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: Mesenchymemesenchymal cells, matrix and no fibers

4. Connective tissue: • Connective tissue proper • Blood • Cartilage • Bone

5. Connective tissue proper: • Loose connective tissue • Dense connective tissue • Adipose tissue • Reticular tissue

6. 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:

7. components: • (1) intercellular substances: fibers ground substance • (2) cells:

8. 2.1 Fibers • collagenous fibers • reticular fibers • elastic fibers

9. 2.1.1 collagenous fibers • Structure • LM sectionstretch Collagenous fibril • EM Collagenous fibril: collagenous fibril with periodic cross striation • Chemical component: collagen (type Ⅰ, Ⅲ )

12. 2.1.2 reticular fibers • Stucture: LM EM • Distribution:terminal web • Chemical component collegen (type Ⅲ ) argyrophil fibers

14. 2.1.3 elastic fibers • Stucture • LM • EM • elastin in the core • microfibril in periphery • Function: keep organs position and shape

16. 2.2 ground substance • Proteoglycan • Glycoprotein • Tissue fluid

17. 2.2.1 proteoglycan • glycosaminoglycan: • hyaluronic acid • chondroitin sulfate A,C • keratin sulfate • heparan sulfate • Function • molecular sieve

18. 2.2.2 glycoprotein: • fibronectin • laminin • chondronnectin

20. 2.2.3 tissue fluidThe plasma is filtered out capillary to form tissue fluid

21. 2.3 cells • fibroblasts • fat cells • undifferentiated mesenchymal cells • macrophages • plasma cells • mast cells • white blood cells

22. 2.3.1 fibroblasts, fibrocytes • Structure • LM stellate, weekly basophillic. Nucleus appears ovoid, pale and clear nucliolus • EM • Function: production of fibers and matrix

25. 2.3.2 fat cells • Structure • Function: energy reservoir, shock-absorbent padding and insulating layer of body heat.

27. 2.3.3 undifferentiated mesenchymal cells • Structure • Function: differentiate into various connective tissue cell-types

28. 2.3.4 macrophages • 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

31. Function of Macrophages • Chemotaxis, chemotactic factor • Phagocytosis • Secretion: lysozyme, interferon, complement. • Immune reaction(response): • antigen-presenting cells, APC • immune effect cells • immune regulation: cytokines

32. 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

34. 2.3.6 mast cells • distribution：along the small blood vessels • structure • LM: metachromatic granules in cytoplasm • EM：lysosome and secretory granules • origin • function: allergic reaction and • degranulation • heparin ------ anticoagulant • histamin ----allergy • leukotriene----allergy

37. 2.3.7 white blood cells

38. 3. dense connective tissue • 1)  dense irregular connective tissue • 2) dense regular connective tissue • 3)  elastic tissue

41. 4. adipose tissue • White (yellow) adipose tissuefat 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

42. 5. reticular tissue  • reticular cellslook stellate and form the web with other cells • reticular fibers tree-like and form the web • ground substances