1. Connective tissue (1) 1.Loose connective tissue (No.4, No.1 )
2.Dense connective tissue (No.14)
3.Adipose tissue (No.14/ No.6)
4.Reticular tissue (No.6)

2. 1. General features:
1) small number of cells and large amount of extracellular matrix (intercellular material).
2) the extracellular matrix is composed of fibers and an amorphous ground substance.
3) functions: connection, supporting, protecting, nutrition, defense and repairing.

3. 2. Classification Connective tissue proper Cartilage Bone blood
The types of CT are determined on the basis of the types of cell and the characteristics of the extracellular matrix

4. connective tissue proper
CT in narrow sense means connective tissue proper, include:
loose CT
adipose tissue
reticular tissue
dense CT

5. Loose connective tissue
Material: rabbit mesentery
Slide No:4
High power:
1. Elongated and tortuous collagenous fibers are stained red and arranged in bundles.
2. The elastic fibers are blue stained, branched and formed a woven network.
3. The fibroblast is the cell most commonly in close to the collagen fiber. Its basophilic nucleus is visible.
4. For the macrophage, its cytoplasm contains some blue dye substance.
LCT：HE X400

6. fiber
Low power: fibers are loosely and irregularly arranged.
high power:
Elongated and tortuous collagenous fibers are stained red and arranged in bundles.
Elastic fibers are blue stained,branched and formed a woven network.

7. Cell
Macrophage: ingest the blue dye by phagocytosis so they can be easily identified.
Fibroblast: the most commonly cell in close to the collagen fiber.only the basophilic nucles is visible,but the acidophilic cytoplasm is not clearly defined.

8. Fibroblast
Macrophage

9. The lightly stained submucosa between mucosa and smooth muscle layer.
Slide No:1
Method: H.E
lower power:
The lightly stained submucosa between mucosa and smooth muscle layer.
Small intestine: HE X40

10. Low power： 1
submucosa

11. Fibroblast collagenous fibers High power:
collagenous fibers are the predominant component and they course in different direction. They are sectioned in various planes and cut ends is seen. stained red and arranged in bundles.
Fibroblast
Fibroblast are the most numerous cells ,only the basophilic nucles is visible,but the acidophilic cytoplasm is not clearly defined.
collagenous fibers
Small intestine: LCT HE X400

12. Dense connective tissue and adipose tissue
Slide No:14
Material: human skin from finger
Method: H.E
Naked eye: in the section, epidermis is violent stained. Under epidermis, the dermis is pink and composed of dense connective tissue.
In hypodermis, you can find loose connective tissue and adipose tissue.
Skin :DCT HE X40

13. Low power:
In the section , epidermis is violent stained. Under epidermis,the dermis is pink and compose of denes connective tissue.
epidermis
dermis

14. high power:
collagenous fibers are the predominant component and they course in different direction. They are dense ,irregularly arranged and formed thic bundles. stained red .The numbers of cells are few, most of which are fibroblasts and fibrocytes.

15. Dense regularly connective tissue
High power:
Collagenous fibers are arranged in compact,parallel bundles
Tendon cell:
Tendon(longitudinal section)

16. Reticular tissue Slide No.5 Material: lymph node of cat Method: H.E
High power:
Reticular cell: A reticular cell produces reticular fiber and surrounds the fibers with its cytoplasm.
It has many processes. Its nuclei is lightly stained, but the nucleolus is clear.
Lymph node: Reticular tissue HE X400

17. Reticular tissue
Lymph node: Reticular tissue HE × 400

18. Reticular tissue ①reticular cell ②lymphocyte ③macrophage

19. Lymph node: Reticular tissue Silver × 400

20. Adipose tissue Slide NO: 6 Material: human lymph node Method: H&E
Low power:
Fat cell are present in large accumulations, orgnized into adipose tissue
Lymph node：Adipose tissue HE X40

21. high power:
Individual Fat cells show their chracteristic structure,empty cells,due to solution of fat during section preparation.
The nucleus is pushed to the periphery of the cell.

22. Fibroblast
Macrophage

23. Mast cells 1.Round and large cell 2.Small dark-stained nucleus
3.Basophilic secreting granules--metachromatically

24. Plasma cell 1.Round or ovoid in shape
2.Nucleus with more clock-liked heterochromatin which located eccentrically
3.Basophilic cytoplasm

25. Collagenous fibers
collagenous fibril

26. fibroblast
Plasma cell
Mast cell
macrophagy

27. The drawing Loose connective tissue H&E stain 400× Collagenous fiber
Macrophage
Elastic fibers
Fibroblast
Loose connective tissue
H&E stain 400×