Chapter 1Chapter 1

IntroductionIntroduction

zhong jie Li ( 李仲杰 )

School of Medicine, Zhejiang University Email ： lizhongjie@zju.edu.cn

Reference booksReference books• 1. 1. 《《组织学与胚胎学组织学与胚胎学》》，人民卫生出版社，，人民卫生出版社， 88 年制、年制、 77 年制和年制和 55 年年

制本科规划教材均可；制本科规划教材均可；

• 2. 2. 唐军民、李继承唐军民、李继承 . . 组织学与胚胎学（组织学与胚胎学（ Textbook of Histology Textbook of Histology and Embryologyand Embryology ）） , , 北京大学医学出版社北京大学医学出版社 , 2011, 2011

• 3. William k. Ovalle & Patrick C. Nahirney. Netter’s essential 3. William k. Ovalle & Patrick C. Nahirney. Netter’s essential histology, Elsevier Health Sciences,2007histology, Elsevier Health Sciences,2007

• 4. Gaetner MP, Hlatt JL. Colour Textbook of Histology. 4. Gaetner MP, Hlatt JL. Colour Textbook of Histology. Williams & Wilkins, 1997Williams & Wilkins, 1997

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)Paper2)Pencils (red-blue pencil) 3)rubber, ruler and so on

m-learning.zju.edu.cn

Course website

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:

Introduction

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 :Histology :

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

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

（（ 16651665 年，英国人，年，英国人， HookeHooke ））Tissue:Tissue: group of cell and extracellular matrix group of cell and extracellular matrix （（ 18011801 年，法国医生比沙，年，法国医生比沙， BichatBichat ）） Four basic tissue: Four basic tissue: ---Epithelial tissue---Epithelial tissue ---Connective tissue---Connective tissue ---Muscular tissue---Muscular tissue ---Nervous tissue---Nervous tissue

TissueTissue

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.

组织学内容关系图解组织学内容关系图解

基本组织 器官系统

上皮组织

结缔组织

肌 组 织

神经组织

循环系统 消化系统

呼吸系统 泌尿系统

生殖系统 免疫系统

内分泌系统 感官

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 itIII.    How to study it

histological methodshistological methods

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

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

Light MicroscopyLight Microscopy

The resolution of the light microscope is 0.2 um

The procedures of paraffin sectioning and H The procedures of paraffin sectioning and H & E staining. & E staining.

• 1. 1. ObtainingObtaining

• 2. 2. FixationFixation

• 3.3.DehydrationDehydration

• 4. 4. ClearingClearing

• 5. 5. EmbeddingEmbedding

• 66. . SectioningSectioning

• 7. 7. StainingStaining

• 8. 8. MountingMounting

Stain methodsStain methods H.E

Hematoxylin苏木精

Eosin伊 红

Acidic stucture ：NucleusRERFree ribosome

Basic stucture ：Cytoplasmalysosome 、 Mit.,fibers

H&EH&E stainingstaining

H&E staining

TEM: TEM: transmission electron transmission electron microscopymicroscopy

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

（ 1932 年， Ruska and Knoll ）

Basophilic granulocyte (LM)

Basophilic granulocyte

(TEM)

SEM: SEM: scanning electron microscopyscanning electron microscopy

The resolution of SEM is about 5nm.

激光扫描共聚焦显微镜 Laser scanning confocal microscope

Histochemistry & Cytochemistry

Immunohistochemistry

Cell culture & Tissue engineering

Learning methodsLearning methods ：：

• Must think in Must think in 3 dimensions3 dimensions

• Structure and functionStructure and function

• part and whole.part and whole.longitudinal section

Horizontal section

oblique section

Changes in apparent shape, due to orientation of sections

Netter/Ciba

Junqueira fig 1-30

Structure and function

relaxation

contraction

part and whole

Chapter 2Chapter 2

Epithelial tissueEpithelial tissue

1.General feature:1.General feature:1) contain more cells and less extracellular ground substance1) contain more cells and less extracellular ground substance2) Polarisaton2) Polarisaton:: ---free surface---free surface ---basal surface---basal surface ---lateral surface---lateral surface3)  Avascularity, but innervation3)  Avascularity, but innervation: : ---no blood vessels---no blood vessels ---rich in nerve terminals---rich in nerve terminals4)4) Cellular Layer + Basement Membrane Cellular Layer + Basement Membrane55) Functions: ) Functions: protectionprotection secretionsecretion absorptionabsorption sensory receptionsensory reception

2.Classification of Epithelium2.Classification of Epithelium

1)1)    Covering epithelium:Covering epithelium: the epithelium which cover body the epithelium which cover body surface or line the inner surface of body cavities, tubes surface or line the inner surface of body cavities, tubes and sac.and sac.

2)2)    Glandular epithelium:Glandular epithelium: the epithelium which main the epithelium which main function is secretion.function is secretion.

3)3)    Special epitheliumSpecial epithelium

* * Sensory epithelium: the epithelium which has special Sensory epithelium: the epithelium which has special sensory function.sensory function.

* * Myoepithelial cellMyoepithelial cell

3. Classification of covering epithelium3. Classification of covering epithelium: :

According to the number of layer and shape of According to the number of layer and shape of cellscells

Simple epi.:Simple epi.: --- ---simple squamous epi.simple squamous epi.

---simple cuboidal epi.---simple cuboidal epi.

---simple columnar epi.---simple columnar epi.

---pseudostratified ciliated columnar epi.---pseudostratified ciliated columnar epi.

Stratified epi.:Stratified epi.: ---stratified squamous epi.---stratified squamous epi.

---stratified columnar epi.---stratified columnar epi.

---transitional epi.---transitional epi.

Cell shapeCell shape

Cell Layers

Simple

Stratified

1)1)            simple squamous epi:simple squamous epi:

---structural feature:---structural feature:

/one layer flattened cells, cell border are interdigitate /one layer flattened cells, cell border are interdigitate closelyclosely ，， polygonal in shape.polygonal in shape.

/with flattened ellipsoid nucleus/with flattened ellipsoid nucleus

---Distribution: ---Distribution: • mesothelium:mesothelium: which line the inner surface of body cavities such as which line the inner surface of body cavities such as

pleura, pleura, peritoneum peritoneum and and pericardium.pericardium.

• endothelium:endothelium: which line the inner surface of cardiovascular and lymph which line the inner surface of cardiovascular and lymph

vessels.vessels.

• other placeother place:: alveoli, parietal layers of renal capsule.alveoli, parietal layers of renal capsule.

---function:---function: a) transport of materials a) transport of materials b) facilitates movement of viscerab) facilitates movement of viscera

endothelium ( 内皮 ) mesothelium ( 间皮 )

Vascular Vascular endotheliumendothelium

2)2)            simple cuboidal epi.:simple cuboidal epi.:

---structural feature:---structural feature: • one layer of cells, with same height and width , hexagonal in one layer of cells, with same height and width , hexagonal in

shape.shape.• spherical centrally-located nucleusspherical centrally-located nucleus

---distribution:---distribution:

/the renal tubule /thyroid /the some ducts of glands/the renal tubule /thyroid /the some ducts of glands

---function:---function: absorption and secretion absorption and secretion

thyroidrenal tubule

3)3)            simple columnar epi.:simple columnar epi.:

----structural features:--structural features: • one layer of columnar cells, with basally located long one layer of columnar cells, with basally located long

ovoid nucleusovoid nucleus

---distribution:---distribution: gastrointestinal tract gastrointestinal tract gall bladdergall bladder uterusuterus---function:---function: secretion and absorption secretion and absorption

* goblet cell* goblet cell: scattered, secreting granules-mucus: scattered, secreting granules-mucus

goblet cellsimple columnar epi

4)4)            pseudostratified ciliated columnar epi.:pseudostratified ciliated columnar epi.:

---Structural feature:---Structural feature: 1, Four types of cells1, Four types of cellscolumnar cell (ciliated); goblet cellcolumnar cell (ciliated); goblet cellfusiform cell; basal cell: pyramid-shapedfusiform cell; basal cell: pyramid-shaped

2, Every cell locate on basement membrane: 2, Every cell locate on basement membrane: Simple epi.Simple epi.

four types of cells

---distribution:---distribution:

inner surface of large inner surface of large duct of respiratory passagesduct of respiratory passages

tracheatrachea

bronchibronchi

nasalnasal

The epithelium of trachea

5)5)            stratified squamous epi.:stratified squamous epi.:

---structural features:---structural features: • deepest (basal) cells: deepest (basal) cells: one layer of cuboidal cellsone layer of cuboidal cells• the cells in intermediate regions: the cells in intermediate regions: several layers of several layers of

polygonal –shaped cells polygonal –shaped cells • to the surface: to the surface: more and more flattened cellsmore and more flattened cells

---distributon:---distributon:

• non-keratinised:non-keratinised: mouth, pharynx, oesophagus, mouth, pharynx, oesophagus, urethra and vaginaurethra and vagina

• keratinised:keratinised: the surface of body, make up the the surface of body, make up the skinskin

non-karatinised karatinised

6 ） stratified columnar epithelium

---Structural features: suface layer: : one layer of columnal cells

deeply regions: several layers of polygonal shaped cells

---Ditribution:

Conjunctiva( 结膜）、 male urethra （男性尿道）

7)7)    transitional epithelium:transitional epithelium:• Flexible qualitiesFlexible qualities

------ Cell shape and the layer variable Cell shape and the layer variable

in the distendeddistended bladder

---distribution: bladder

in the in the contracted bladderbladder

4. 4. Epithelial Epithelial specializations specializations

Sides of cells:--- Apical (free)--- Basal--- Lateral

1)1)            Specializations of free surfaceSpecializations of free surface

①①        microvilli:microvilli: ---definition:---definition: delicate finger-liked projections of cell- delicate finger-liked projections of cell-

membrane and cytoplasm protruding from the free surfacemembrane and cytoplasm protruding from the free surface

---structure:---structure: • 0.1um in diameter, with different longth.0.1um in diameter, with different longth.• surface: cell membrane with cell coatsurface: cell membrane with cell coat• corecore: longitudinal microfilament-actin filament : longitudinal microfilament-actin filament

fixed on terminal webfixed on terminal web• terminal web: made up of transverse-arranged terminal web: made up of transverse-arranged

filament at the apical side of cellsfilament at the apical side of cells

---function:---function: increase the surface areas, thus aid in the increase the surface areas, thus aid in the processes of secretion and absorption.processes of secretion and absorption.

---distribution:---distribution: /striated border: intestinal epi. cell /striated border: intestinal epi. cell

/brush border: proximal renal tubule/brush border: proximal renal tubule

Striated borderStriated border

②② cell coat:cell coat:

---definition:---definition: a thick layer of extracellular glycoproteina thick layer of extracellular glycoprotein

---function:---function: adherence, supporting, protection, exchange of material and recognizeadherence, supporting, protection, exchange of material and recognize

     ③     ③ cilia:cilia:---definition:---definition: elongated, mobile projections of cell elongated, mobile projections of cell

membrane and cytoplasm protruding from free membrane and cytoplasm protruding from free surfacesurface

---structure:---structure:

• 5-10um long, 300-500nm in diameter5-10um long, 300-500nm in diameter

• surface: cell membranesurface: cell membrane

• core: microtubules, 9X2+2core: microtubules, 9X2+2

• basal body: basal body:

centrioles-connected with microtubules of ciliacentrioles-connected with microtubules of cilia

---function:---function: beat in a rhythmical manner and produce a beat in a rhythmical manner and produce a forward-moving wave forward-moving wave

---distribution:---distribution: epithelial cells of respiratory tract epithelial cells of respiratory tract

respiratory tract

2)2)    specializations specializations of the lateral surface of the lateral surface

---intercellular connection of adjacent cells: ---intercellular connection of adjacent cells:

• non-special manner: the minute space and adherent non-special manner: the minute space and adherent molecules (glycoproteins, proteoglycans, cadherin)molecules (glycoproteins, proteoglycans, cadherin)

• Special manner: junctional structuresSpecial manner: junctional structures

①①  Tight junction (zonula occludens):Tight junction (zonula occludens):

---structure:---structure: • apical partapical part

• point-liked fused between adjacent point-liked fused between adjacent cellscells• arranged in 2-4 thread-likedarranged in 2-4 thread-liked structuresstructures• form anastomosing networkform anastomosing network

---function:---function: seal the space between cellsseal the space between cells

---structure: ---structure: • below the tight junctionbelow the tight junction• a gap of 15-20nm in width with a gap of 15-20nm in width with

medium electron-density filament medium electron-density filament materialmaterial

• plaque plaque of electron-dense materials, of electron-dense materials, with attached microfilament-make up with attached microfilament-make up of of terminal webterminal web

---function:---function: /adherens/adherens /keep the cell shape/keep the cell shape /transfer cell contract force/transfer cell contract force

 ② ② intermediate junction (zonula adherens):intermediate junction (zonula adherens):

③③ desmosome (macula adherens):desmosome (macula adherens):

---structure:---structure:

• plate or spot-shapedplate or spot-shaped

• a gap of 20-30 nm, witha gap of 20-30 nm, with

low electron-density filaments low electron-density filaments

interdigitateinterdigitate

• attachment plaqueattachment plaque

Many tonofilaments are inserted into Many tonofilaments are inserted into attachment plaque, each filament attachment plaque, each filament make a hairpin loop and then passes make a hairpin loop and then passes back into the cytoplasmback into the cytoplasm

• ---function:---function:

firmly connectionfirmly connection

---structure:---structure: • the smallest gap of 2-3 nmthe smallest gap of 2-3 nm• connexonsconnexons:: -consist of protein-consist of protein -7~9nm in diameter-7~9nm in diameter -composed of 6-subunits of -composed of 6-subunits of

proteinsproteins- connexin- connexin -2nm channel: electron-lucid -2nm channel: electron-lucid

central channelcentral channel---function:---function: provide a ions and small molecules provide a ions and small molecules

pathway between cellspathway between cells

④ gap junction (communication junction):

connexons

junctional complex:junctional complex:

at least two types of junctional structures get at least two types of junctional structures get together.together.

3)3)            specialization of basal surfacespecialization of basal surface

①①    basement membrane:basement membrane:---definition:---definition: a sheet of membrane-liked amorphous a sheet of membrane-liked amorphous

material interposed between epithelium cells and material interposed between epithelium cells and underlying CT.underlying CT.

---structure:---structure:

• HE: pink colour, hard to seeHE: pink colour, hard to see

• PAS +PAS +

• EM: two layersEM: two layers ----basal laminabasal lamina: 20-100 nm, electron-dense, thread-: 20-100 nm, electron-dense, thread-

liked and amorphous ground substance, produced liked and amorphous ground substance, produced by epithelium cell.by epithelium cell.

----reticular laminareticular lamina: RT+ground substance, produced : RT+ground substance, produced by CTby CT

---function:---function:

• support, connection, fixationsupport, connection, fixation

• semi-permeable membranesemi-permeable membrane

• induce the movement, proliferation and induce the movement, proliferation and differentiation of epithelium celldifferentiation of epithelium cell

 ② ② plasma membrane infoldingplasma membrane infolding

(basal longitudinal striation):(basal longitudinal striation): ---definition:---definition: the infolding of cell-membrane with many the infolding of cell-membrane with many

mitochondria at the basal surface of epithelium cellmitochondria at the basal surface of epithelium cell

---function:---function:

• increase the basal surface areasincrease the basal surface areas

• facilitate the passage of water and ionsfacilitate the passage of water and ions

---distribution:---distribution: mainly in proximal and distal renal mainly in proximal and distal renal tubule.tubule.

③③    hemidesmosomeshemidesmosomes

---is half of desmosome.---is half of desmosome.

SUMMARY 1SUMMARY 1 ：：上皮类型 主要分布

单层上皮 单层扁平上皮 内皮：循环管道内表面间皮：胸膜、腹膜、心包膜、其它：肺泡、肾小囊等

单层立方上皮 肾小管、甲状腺滤泡等单层柱状上皮 胃肠、胆囊、子宫内膜等假复层纤毛柱状上皮 呼吸管道

复层上皮 复层扁平上皮 角化型：皮肤表皮非角化型：口腔、食管、阴道

复层柱状上皮 睑睫膜、男性尿道等变移上皮 肾盏、肾盂、输尿管、膀胱

SUMMARY 2SUMMARY 2 ：：名 称 结 构 特 点 主 要 功 能

游离面微绒毛 细指状，光镜不可见，有微丝 吸收

纤毛 粗指状，光镜下可见，有微管 定向摆动

侧 面

紧密连接 点状融合 机械连接

中间连接 小盘状融合 机械连接

桥粒 斑状融合 机械连接

缝隙连接 点状，成群，细胞间有通道 细胞通讯

基底面

基膜 薄膜，分基板和网板， PAS 阳性，嗜银

连接、支持、半透膜

质膜内褶 膜向胞内折叠，线粒体多 吸收

半桥粒 桥粒的一半 固定

Questions Questions

• Describe the characteristics of epithelial tissue.Describe the characteristics of epithelial tissue.• Describe the structural characteristics, Describe the structural characteristics,

distribution and functions of each type distribution and functions of each type covering epithelial.covering epithelial.

• Compare the structure of microvilli with cilia.Compare the structure of microvilli with cilia.• Compare the structure of intermediate junction Compare the structure of intermediate junction

with desmosome.with desmosome.

Preview:Preview:

• Connetive tissue.Connetive tissue.• Cartilage.Cartilage.

5. Glandular epithelium and gland 5. Glandular epithelium and gland (study yourself )(study yourself )

• glandular epithelium: are specialized for secretionglandular epithelium: are specialized for secretion• gland: organs composed mainly of glandular gland: organs composed mainly of glandular

epiitheliumepiithelium

1) Classification:1) Classification: exocrine gland: exocrine gland: discharge the secretion through a duct systemdischarge the secretion through a duct systemendocrine gland: endocrine gland: release the secretion directly into blood steamrelease the secretion directly into blood steam

2) structure of exocrine gland: 2) structure of exocrine gland:

Simple gland compound alveolar gland compound tubulo-alveolar glandSimple gland compound alveolar gland compound tubulo-alveolar gland

① acinus (secreting unit): according the nature of secretion

a. serous acinus: serous secretory cells

---structure:---structure: • pyramid-shaped cellpyramid-shaped cell• basally-located round nucleusbasally-located round nucleus• acidophilic cytoplasm-eosinophilic zymogen acidophilic cytoplasm-eosinophilic zymogen

granules-contain enzymesgranules-contain enzymes• EM: RER, Golgi complexEM: RER, Golgi complex---function:---function: produce a serous secretion produce a serous secretion

b. Mucous acinus:b. Mucous acinus: mucous secreting cells mucous secreting cells

---structure:---structure:

• pyramid-shaped cellpyramid-shaped cell

• flattened dark nucleus against the basal cell flattened dark nucleus against the basal cell membranemembrane

• slightly basophilic cytoplasm-large mucigen slightly basophilic cytoplasm-large mucigen granulesgranules

• EM: some RER, Golgi complexEM: some RER, Golgi complex

---function:---function: secretes mucus secretes mucus

Mucous acinusMucous acinus

c.c.    mixed acinus:mixed acinus: two types of cells two types of cells ---structure:---structure: • mucous acinusmucous acinus• with several serous cells attach on one side- serous demilunewith several serous cells attach on one side- serous demilune

②②    ducts: ducts:

---from simple squamous epithelium to simple ---from simple squamous epithelium to simple columnar or stratified epitheliumcolumnar or stratified epithelium

---carry out the secretions---carry out the secretions

---secrete or absorb water and ions---secrete or absorb water and ions

Thank you !Thank you !

Preparation of tissue for LMPreparation of tissue for LM

The most routine one is paraffin section The most routine one is paraffin section stained with hematoxylin and eosin(H&E)stained with hematoxylin and 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 organizationBouin’s to preserve structural organization

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

Supplementary material:

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 monted them on glass slidesmonted them on glass slides

g.   g.   H&E stainingH&E staining

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

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

The steps are same to preparation for LMThe steps are same to preparation for LM

a.   tissue block: more small, less than a.   tissue block: more small, less than 1mm1mm33

b.   plastic materials for embeddingb.   plastic materials for embedding

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

d.   heavy metal salts- increase staining d.   heavy metal salts- increase staining contrastcontrast

---lead citrate---lead citrate

---uranyl acatate---uranyl acatate

Preparation of tissue for EMPreparation of tissue for EM