Connective Tissue

1. General characteristics Features: 1. Small number cells and a large amount of matrix 2. No polarity and filled with blood and vessels 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 Distribution: widely in the body Function: connection, support, nutrition transportation and protection Function: connection, support, nutrition transportation and protection Origin: Mesenchyme mesenchymal cells, matrix and no fibers Origin: Mesenchyme mesenchymal cells, matrix and no fibersMesenchyme

Connective tissue: Connective tissue proper Connective tissue proper Blood Blood Cartilage Cartilage Bone Bone

Connective tissue proper: Loose connective tissue Loose connective tissue Dense connective tissue Dense connective tissue Adipose tissue Adipose tissue Reticular tissue Reticular tissue

2.Loose connective tissue (areolar tissue) structural features: (1)a great variety of cell. (2)small number fibers structural features: (1)a great variety of cell. (2)small number fibers distribution: widely among organs and tissues. distribution: widely among organs and tissues. function: connection and support, defense and repair function: connection and support, defense and repair components: components:

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

2.1 Fibers collagenous fibers collagenous fibers reticular fibers reticular fibers elastic fibers elastic fibers

2.1.1 collagenous fibers Structure Structure  LM section stretch sectionstretchsectionstretch Collagenous fibril Collagenous fibril  EM Collagenous fibril: collagenous fibril with periodic cross striation EM Chemical component: Chemical component: collagen (type Ⅰ, Ⅲ ) collagen (type Ⅰ, Ⅲ )

2.1.2 reticular fibersreticular fibers Stucture: LM EM Stucture: LM EMEM Distribution:terminal web Distribution:terminal web Chemical component Chemical component collegen ( type Ⅲ ) collegen ( type Ⅲ ) argyrophil fibers argyrophil fibers

2.1.3 elastic fibers Stucture Stucture  LM LM  EM EM  elastin in the core  microfibril in periphery Function: keep organs position and shape Function: keep organs position and shape

2.2 ground substance Proteoglycan Proteoglycan Glycoprotein Glycoprotein Tissue fluid Tissue fluid

2.2.1 proteoglycanproteoglycan glycosaminoglycan: glycosaminoglycan:  hyaluronic acid  chondroitin sulfate A,C  keratin sulfate  heparan sulfate Function Function  molecular sieve

2.2.2 glycoprotein: fibronectin fibronectin laminin laminin chondronnectin chondronnectin

2.2.3 tissue fluid The plasma is filtered out capillary to form tissue fluid

2.3 cells fibroblasts fibroblasts fat cells fat cells undifferentiated mesenchymal cells undifferentiated mesenchymal cells macrophages macrophages plasma cells plasma cells mast cells mast cells white blood cells white blood cells

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

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

2.3.3 undifferentiated mesenchymal cellsundifferentiated mesenchymal Structure Structure Function: differentiate into various connective tissue cell- types Function: differentiate into various connective tissue cell- types

2.3.4 macrophages Types Types  Histocytes: fixed in loose connective tissue  wandering macrophages: wandering to inflammation area Structure Structure  LM: phagosome LM:  EM: lysosome EM: Origin: Origin: Function ： phagocytosis, antigen presenting and secreting lysozyme and complement Function ： phagocytosis, antigen presenting and secreting lysozyme and complement

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

2.3.5 plasma cells Distribution: digestive tract, respiratory tract Distribution: digestive tract, respiratory tract Structure Structure  LM:the nucleus is wheel-like  EM: rough endoplasmic reticulum EM: Origin: from B lymphocyte Origin: from B lymphocyte Function: secrete immunoglobin Function: secrete immunoglobin

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

2.3.7 white blood cells

3. dense connective tissue 1) dense irregular connective tissue 1) dense irregular connective tissuedense irregular connective tissuedense irregular connective tissue 2) dense regular connective tissue 2) dense regular connective tissuedense regular connective tissuedense regular connective tissue 3) elastic tissue 3) elastic tissueelastic tissueelastic tissue

4. adipose tissue White (yellow) adipose tissue fat cell appears ring-like: a single large droplet in the cytoplasm, and the flattened nucleus locates the rim White (yellow) adipose tissue fat cell appears ring-like: a single large droplet in the cytoplasm, and the flattened nucleus locates the rim White (yellow) adipose tissue White (yellow) adipose tissue Brown adipose tissue Brown adipose tissue Brown adipose tissue Brown adipose tissue rich of vessel in the tissue. Several small droplets in the cytoplasm, and the nucleus locates in the center rich of vessel in the tissue. Several small droplets in the cytoplasm, and the nucleus locates in the center

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