扬州大学：《组织胚胎学》课程教学课件（讲稿）上皮组织 Epithelial tissue

Chapter 2Epithelial Tissue

Chapter 2 Epithelial Tissue

What is epithelial tissue?2.What are the characteristics of epithelialtissue?3. How to classify covering epithelia?4.What are the specializations ofepithelium?

1. What is epithelial tissue? 2. What are the characteristics of epithelial tissue? 3. How to classify covering epithelia? 4. What are the specializations of epithelium?

1. What is epithelial tissue?

1. What is epithelial tissue?

Conception:Epitheliumisatissuecomposed of closely aggregatedpolyhedral cells and very little extracellularmatrix.Distribution:Cells coverbodysurfaces,line body cavities, and constitute glands

Conception: Epithelium is a tissue composed of closely aggregated polyhedral cells and very little extracellular matrix. Distribution: Cells cover body surfaces, line body cavities, and constitute glands

Classification(1)Coveringepithelium:The epitheliumwhichcover body surfaceorlinethe inner surface of body cavities,tubesandsac.(2)Glandularepithelium:Theepithelium whichmainfunctionissecretion

(1) Covering epithelium: The epithelium which cover body surface or line the inner surface of body cavities, tubes and sac. (2) Glandular epithelium: The epithelium which main function is secretion. Classification

Functions:ProtectionSecretionAbsorptionTransportExcretionOthers: Sensation,

 Protection  Secretion  Absorption  Transport  Excretion  Others: Sensation, . Functions:

2.What are the characteristics ofepithelialtissue?

2.What are the characteristics of epithelial tissue?

Characteristics1.Epithelium covers free surfaces of the body(internalandexternal),forms glands,andtheductsfromglandsororgans.2.Most epithelia havea basement membranewhich attaches the epithelial cells to underlyingtissue.3.Epitheliumis mostly cellswithlittle extracellularmaterial.4.Epithelium is avascular (no blood vessels).Allexchangebetweenepitheliaand bloodtakesplacebydiffusionacrossthebasement membrane.5.Innervation

1. Epithelium covers free surfaces of the body (internal and external), forms glands, and the ducts from glands or organs. 2. Most epithelia have a basement membrane which attaches the epithelial cells to underlying tissue. 3. Epithelium is mostly cells with little extracellular material. 4. Epithelium is avascular (no blood vessels). All exchange between epithelia and blood takes place bydiffusion across the basement membrane. 5.Innervation Characteristics

(1+2)Polarisaton:---free surface: face air or other things;---basal surface: face underlying CT, havebasementmembrane.freesurface一Basementmembrane

(1+2) Polarisaton: -free surface: face air or other things; -basal surface: face underlying CT, have basement membrane. basal surface free surface

(3)Containmorecellsandverysmallamounts of extracellular matrix;福福

(3) Contain more cells and very small amounts of extracellular matrix;