Histology and Embryology Zhong jie Li （李仲杰） School of medicine, Zhejiang University

Chapter 1 Introduction

Relationship: cell --- tissue---organ---system---human body

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

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)

Why medical students should study Histology ? II.

Histology & Embryology Anatomy Physiology Biochemistry Parasitology Patholo gy Microbiology Immunology Pathphysiology Pharmocology Basic medicine &Surgery Clinic (Medicine,Surgery,Gynecology, Pedology, etc.) Intern (exercitation) Graduate

III. How to study it Microscopy: Microscopy: Light microscopy (LM) Light microscopy (LM) Electron microscopy (EM) Electron microscopy (EM) Transmission electron microscope (TEM) Transmission electron microscope (TEM) Scanning electron microscope (SEM) Scanning electron microscope (SEM) Staining: Staining: H&E H&E Histochemistry Histochemistry Immunohistochemistry Immunohistochemistry In situ hybridiztion … In situ hybridiztion …

Relative Sizes in Histology Standard Units of Measure

Light Microscopy  : The resolution of the human eye is 0.2 mm.  : The resolution of the light microscope is 0.2 um.  : The resolution of the light microscope is 0.2 nm.

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 Preparation of tissue for LM

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

Staining g. Staining

--- Hematoxylin: basic dye, combines with acidic components, make them appear blue colour- basophilic, i.e. cell nucleus, hyaline cartilage ---Eosin: acidic dye, combines with basic components, make them appear pink colour- acidophilic (eosinophilic), i.e. cytoplasm basophilic acidophilic (eosinopilic) neutrophilc nucleolus nucleus H&E --- Routine staining for LM

H&E staining

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

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

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. 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 reagents for localizing tissue and cell constituents (antigens) in situ To use labelled antibodies as specific reagents for localizing tissue and cell constituents (antigens) in situ Observation:Fluorescence microscope Observation:Fluorescence microscope

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

Reference books 1. Jun min T, Ji cheng L. Textbook of Histology and Embryology. Peking University Medical Press, Jun min T, Ji cheng L. Textbook of Histology and Embryology. Peking University Medical Press, William k. Ovalle & Patrick C. Nahirney. Netter’s essential histology, Elsevier Health Sciences, William k. Ovalle & Patrick C. Nahirney. Netter’s essential histology, Elsevier Health Sciences, Gaetner MP, Hlatt JL. Colour Textbook of Histology. Williams & Wilkins, Gaetner MP, Hlatt JL. Colour Textbook of Histology. Williams & Wilkins, 1997 Course web: (2015 Histology and Embryology)

The composition of final score: 1. Lecture and Lab attendence: 10 % 2. Quiz: 15% （ each quiz 5% ） 3. Lab test: 25% 4. Final written examination ： 50% Histology ： 35-40% Embryology ： 10-15% *. If you want to pass this course, final written examination score must be more than 50. Preparation of laboratory work Have the tools ready: 1)Pencils (red-blue pencil) 2)rubber, ruler and so on