Histology and EmbryologyHistology and Embryology

Jicheng LIJicheng LIZhejiang University Medical Zhejiang University Medical

SchoolSchool

Reference booksReference books

1.唐军民、李继承 .组织学与胚胎学（ Textbook of Histology and Embryology），北京大学医学出版社， 2011年1月。

2.Junqueira LC, Carneiro J, Kelley RO. Basic Histology. 9th ed. New York: Appleton & Lange, Stamford, Connecticut, 1998

3.Gaetner MP, Hlatt JL. Colour Textbook of Histology. Williams & Wilkins, 1997

4.Su Huici. A Textbook of Histology. China Science and Technology Press, Beijing

Chapter 1Chapter 1IntroductionIntroduction

I.     What’s histology?

II.    Why we study it ?

III.   How to study it ?

-Histological methods.

I. What’s histology?

Histology (Greek words):

/histo-tissue

/logia-study of ,or knowledge of

Histology means the knowledge of tissue, is a branch of Anatomy.

Anatomy:

---gross anatomy

---microscopic

anatomy -- microanatomy

structures related to function.

Histology is a science which study the microstructure and the relationship between the structure and function of human being.

Cell: smallest unit of structure and function of body ↓tissue: group of cell and extracellular ground

substance four basic tissue: --- epithelium ↓ --- connective tissue --- muscular tissue --- nervous tissueorgan: made up of tissue, have special shape,

structure and function ↓system: organs which have related function get

together.

II.What’s Embryology?

Embryology is a kind of science which study the processes and the regulations of the development of human fetus.

1.Preembryonic period

2.Embryonic period

3.Fetal period

III. How to study it- histological methods

---Development of histology depends on the development of technique.

---Histology studies the microstructures. So, we should have the aid of microscope to study. Several types of microscopes are available.

Some Instruments for

Histologcal Research

Light MicroscopyLight Microscopy

Preparation of tissue for LM

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: use formalin or Bouin’s to preserve structural organisation

c.  Dehydration: use ethyl alcohol to get rid of water of tissue and cell

d.  Clearing: use xylene to get rid of alcohol

*alcohol and xylene are embedding mediums

e.  Embedding: 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 mounted them on glass slides

g.   H&E staining

---Hematoxylin: basic stain, combines with acidic components, make them appear blue colour- basophilic, i.e. cell nucleus, hyaline cartilage

---Eosin: acidic stain, combines with basic components, make them appear pink colour- acidophilic (eosinophilic), i.e. cytoplasm

  H&E stainingH&E staining

TEMTEM

The steps are same to preparation for LM

a.   tissue block: more small, less than 1mm3

b.   plastic materials for embedding

c.  ultra-thin sections is about 30-50nm thick( use ultramicrotome)

d.   heavy metal salts- increase staining contrast

---lead citrate

---uranyl acatate

Preparation of tissue for EMPreparation of tissue for EM

Basophilic granulocyteBasophilic granulocyte (LM)

Basophilic granulocyteBasophilic granulocyte

(TEM)(TEM)