1. Introduction

2. What is Histology?
Why to study Histology?
Techniques on Histology
How to study Histology?

3. Histology and Embryology
Histology is a science which study the microstructure and the relationship between the structure and function of human being.
Embryology is a science which study the processes and regulations of development of human fetus.

4. Histology：
/histo-tissue
/ology-study of ,or knowledge of
So, histology means the knowledge of tissue,
is a branch of Anatomy
a science to study the fine structure associated with its function in the human body.

5. smallest unit of structure and function of body
Cell :
smallest unit of structure and function
of body
tissue: group of cell+extracellular metrix
organ: several tissues combined orderly
system:organs Which have related function get together.

6. four kinds of basic tissues
epithelium
connective tissue
muscular tissue
nervous tissue

7. Techniques on Histology
Development of histology
depends on the development of techniques.
microscope
light microscope(LM)
electron microscope(EM)

8. the measuring unit
LM : um
EM : nm

9. paraffin section preparation
1. Tissue preparation
paraffin section preparation
The most routine one is paraffin section stained with hematoxylin and eosin(H&E)
The steps:
a. Obtaining the specimen: fresh, small pieces ( less than 5mm3)-tissue block
b. Fixation: to avoid digestion and to preserve the structure,use fixatives( formalin )
c.  Dehydration: use ethyl alcohol to get rid of water of tissue and cell
d.  Clearing: use xylene to get rid of alcohol

10. e.  Embedding:
Embedding materials include paraffin and resin.
Paraffin is used routinely .
firstly, heat the paraffin, make it melt, then put tissue block into melted paraffin, allow paraffin harden, the tissue block is embedded in.
f.   Sectioning: use microtome to cut the tissue into 3-8um thick sections, then put them on glass slides

11. 2. Staining
( H&E stain)
---Hematoxylin: basic dye, combines with acidic components, make them appear blue colour
basophilic

12. ---Eosin: acidic dye, combines with basic components, make them appear pink
acidophilic

13. electron microscope ( EM)
TEM
SEM

14. Histochemistry 1) General Histochemistry
Combine histological methods with chemical or biochemical methods, make some compositions of tissue or cell become insoluble, coloured or electron-dense, to show those chemical compositions of tissue or cell in situ, such compositions includes protein,amino acid, nucleic acid, lipid and polysaccharides.

15. Periodic acid schiff reaction(PAS reaction):
polysaccharides and glycogen

16. 2) immnohistochemistry:

17. 3) in situ hybridization

18. Autoradiograph
Tissue culture and cell culture

19. How to study Histology?

20. Cell of Human body