Histology and EmbryologyHistology and Embryology

Zhong jie Li Zhong jie Li （（李仲杰）李仲杰）

School of medicine, Zhejiang School of medicine, Zhejiang UniversityUniversity

lizhongjie@zju.edu.cnlizhongjie@zju.edu.cn

Chapter 1Chapter 1

IntroductionIntroduction

Relationship:

cell --- tissue---organ---system---human body

I.     What’s histology?I.     What’s histology?

II.    Why we study it ?II.    Why we study it ?

III.   How to study it ?III.   How to study it ?

---Histological methods.---Histological methods.

Key points:

I. What’s histology?I. What’s histology?

Histology (Greek words): Histology (Greek words):

/histo---tissue/histo---tissue

/logia---study of ,or knowledge of /logia---study of ,or knowledge of

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

Anatomy: Anatomy:

---gross anatomy---gross anatomy

---microscopic anatomy/microanatomy---microscopic anatomy/microanatomy

Histology :Histology :

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

Cell:Cell: smallest unit of structure and function of smallest unit of structure and function of bodybody

Tissue:Tissue: group of cell and extracellular matrix 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 organthe cavity organ --- parenchymatous organparenchymatous organ

anatomy

histology

System: organs which have related function get together.

What’s Embryology?What’s Embryology?

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

Pathology

MicrobiologyImmunology

Pathphysiology Pharmocology Basic medicine &Surgery

Clinic (Medicine,Surgery,Gynecology, Pedology, etc.)

Intern (exercitation)Graduate

III.    How to study itIII.    How to study it

• Microscopy:Microscopy:

Light microscopy (LM)Light microscopy (LM)

Electron microscopy Electron microscopy (EM)(EM)• Transmission electron microscope (TEM)Transmission electron microscope (TEM)

• Scanning electron microscope (SEM)Scanning electron microscope (SEM)

• Staining:Staining:

H&E H&E

HistochemistryHistochemistry

ImmunohistochemistryImmunohistochemistry

In situ hybridiztion …In situ hybridiztion …

Relative Sizes in Histology

Standard Units of Measure

Light MicroscopyLight 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 The most routine one is paraffin section stained with hematoxylin and stained with hematoxylin and eosin(H&E)eosin(H&E)

The steps:The steps:

a.a.  Obtaining the specimen:Obtaining the specimen: fresh, small fresh, small pieces tissue block( less than 5mmpieces tissue block( less than 5mm33))

b.b.  Fixation: fixatives:Fixation: fixatives: use formalin or use formalin or Bouin’s to preserve structural Bouin’s to preserve structural organizationorganization

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

Preparation of tissue for LM

d.d.    Clearing:Clearing: use xylene use xylene to get rid of alcoholto get rid of alcohol

*alcohol and xylene are *alcohol and xylene are embedding mediumsembedding mediums

e.e.    Embedding:Embedding: firstly, firstly, heat the paraffin, make heat the paraffin, make it melt, then put tissue it melt, then put tissue block into melted block into melted paraffin, allow paraffin paraffin, allow paraffin harden, the tissue harden, the tissue block is embedded in.block is embedded in.

f.f.      Sectioning:Sectioning: use microtome to cut the use microtome to cut the tissue into 3-8um thick sections, then tissue into 3-8um thick sections, then mounted them on glass slidesmounted them on glass slides

g.  Staining 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: TEM: transmission electron transmission electron microscopymicroscopy

The resolution of the TEM is about 0.1-0.5nm.

Basophilic granulocyteBasophilic granulocyte (LM)

Basophilic granulocyteBasophilic granulocyte

(TEM)(TEM)

SEM: SEM: scanning electron microscopyscanning electron microscopy

The resolution of SEM is about 5nm.

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

Histochemistry & Histochemistry & CytochemistryCytochemistry

Periodic acid-Schiff (PAS) reactionLocalize polysaccharides, such as glycogen, in tissues and cells.

PAS+

Produce an insoluble magenta complex

ImmnohistochemistryImmnohistochemistryTo 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 situconstituents (antigens) in situ

Observation:Fluorescence microscopeObservation:Fluorescence microscope

• A method for detection of specific A method for detection of specific RNA or DNA sequences directly in RNA or DNA sequences directly in cells or tissue sectionscells or tissue sections

• incubate tissues with probe to detect incubate tissues with probe to detect cells expressing genecells expressing gene

In Situ HybridizationIn Situ Hybridization

Methods of learning:Methods of learning:---Must think in ---Must think in 3 dimensions3 dimensions

---Structure and function---Structure and function

---part and whole.---part and whole.

Horizontal sectionlongitudinal section

oblique section

Part and whole

舒张状态

收缩状态

Structure and function

Reference booksReference books• 1. Jun min T, Ji cheng L. Textbook of Histology and 1. Jun min T, Ji cheng L. Textbook of Histology and

Embryology. Peking University Medical Press, 2011Embryology. Peking University Medical Press, 2011

• 2. William k. Ovalle & Patrick C. Nahirney. Netter’s essential 2. William k. Ovalle & Patrick C. Nahirney. Netter’s essential histology, Elsevier Health Sciences,2007histology, Elsevier Health Sciences,2007

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

Course web: Course web: http:/http:/m-learning.zju.edu.cn(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