Histology and Embryology Li zhong jie Zhejiang University Medical School

Reference 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, 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, Junqueira LC, Carneiro J, Kelley RO. Basic Histology. 9th ed. New York: Appleton & Lange, Stamford, Connecticut, Junqueira LC, Carneiro J, Kelley RO. Basic Histology. 9th ed. New York: Appleton & Lange, Stamford, Connecticut, Gaetner MP, Hlatt JL. Colour Textbook of Histology. Williams & Wilkins, Gaetner MP, Hlatt JL. Colour Textbook of Histology. Williams & Wilkins, Su Huici. A Textbook of Histology. China Science and Technology Press, Beijing 4.Su Huici. A Textbook of Histology. China Science and Technology Press, Beijing

Chapter 1 Introduction

I. What’s histology? II. Why we study it ? III. How to study it ? ---Histological methods. ---Histological methods. Key points:

I. What’s histology? Histology (Greek words): /histo---tissue /histo---tissue /logia---study of,or knowledge of /logia---study of,or knowledge of Histology means the knowledge of tissue, is a branch of Anatomy.

Anatomy: ---gross anatomy ---gross anatomy ---microscopic anatomy/microanatomy ---microscopic anatomy/microanatomy Histology : a science which study the microstructure and the relationship between the structure and function of human being. 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 matrix Four basic tissue: Four basic tissue: ---Epithelial tissue ---Epithelial tissue ---Connective tissue ---Connective tissue ---Muscular tissue ---Muscular tissue ---Nervous tissue ---Nervous tissue

Tissue

Organ: made up of tissue, have special shape, structure and function the cavity organ --- the cavity organ parenchymatous organ --- parenchymatous organ anatomy histology

System: organs which have related function get together.

What’s Embryology? Embryology is a kind of science which study the processes and the regulations of the development of human fetus. Embryology is a kind of science which study the processes and the regulations of the development of human fetus. --- Preembryonic period --- Preembryonic period --- Embryonic period --- Embryonic period (8 weeks before) (8 weeks before) --- Fetal period (9-38 weeks) --- Fetal period (9-38 weeks)

II. Why we should study it ? Histology is the meeting-place of anatomy 、 physiology 、 pathology and biochemistry. Special structure is related to special function 只有了解正常的机体结构、组成及其基本生命现象， 才能理解机体异常的病理变化。同时也能将生命科学研 究不断引向深入。

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.

Light Microscopy The resolution of the light microscope is 0.2 um

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 tissue block( less than 5mm 3 ) b. Fixation: fixatives: use formalin or Bouin’s to preserve structural organization 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 monted 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 staining

TEM: transmission electron microscopy The resolution of the TEM is about nm.

Basophilic granulocyte (LM) Basophilic granulocyte (TEM) (TEM)

The steps are same to preparation for LM a. tissue block: more small, less than 1mm 3 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 EM

SEM: scanning electron microscopy The resolution of SEM is about 5nm.

To combine histological and cytological methods with chemical and biochemical methods and reveal the chemical composition of tissue and cell in situ. Histochemistry & Cytochemistry

Periodic acid-Schiff (PAS) reaction Localize polysaccharides, such as glycogen, in tissues and cells. PAS+ Produce an insoluble magenta complex

Immnohistochemistry To use labelled antibodies as specific To use labelled antibodies as specific reagents for localizing tissue and cell reagents for localizing tissue and cell constituents (antigens) in situ constituents (antigens) in situ

Cell culture

A method for detection of specific RNA or DNA sequences directly in cells or tissue sections A method for detection of specific RNA or DNA sequences directly in cells or tissue sections incubate tissues with probe to detect cells expressing gene incubate tissues with probe to detect cells expressing gene In Situ Hybridization

Methods of learning: ---Must think in 3 dimensions ---Structure and function ---part and whole. Horizontal section longitudinal section oblique section

Part and whole 舒张状态 收缩状态 Structure and function

Final score of Histology & Embryology 1) Attendance and Picture drawing : 5% 2) Quiz: 10% (each quiz 5%) 3) Lab test: 25% 4) Final written exam: 60% Preparation of laboratory work Have the tools ready: 1)Paper 2)Pencils (red-blue pencil) 3)rubber, ruler and so on