The epithelial Tissue

Department of Histology and Embryology

Epithelial TissuesEpithelial Tissues

• • Classification of Epithelia

①①Cell ShapeCell Shape

• • Classification of Epithelia①①Cell ShapesCell Shapes

②②Cell LayerCell Layer

StratifiedStratified

SimpleSimple

Contents:Contents: 1. Simple squamous epi. ( NO: 25) 2. Simple cuboidal epi( NO: 35) 3. Simple columnar epi. (NO: 1) 4. Pseudostratified ciliated columnar epi. (NO: 3) 5. Stratified squamous epi.( NO: 2) 6. Transitional epithelium ( NO: 33)

Requirement: Master and recognize the main types of covering epithelia.

1.Simple squamous epithelium( surface view)

Material: frog mesentery

Method: silver nitrate stain( Spread slide)

Showpiece: Mesothelium

surface view

cell Irregular polygons

Membrane and extrocellular substance

Mesothelium

Nuclei are not stained,appears oval or rounded shape

The light brown granularcytoplasm

Vascular Vascular endotheliumendothelium

Simple squamous epithelium( lateral view )

Material: Stomach----

Method: H&E

Slide NO. 25

Mesothelium

Cells are flat shaped oblate nuclei

2.Simple cuboidal epithelium

Material: thyroid gland

Method: H&E

Slide NO. 35

Low power:Follicle: many big and small follicles. The

wall is consisted of simple cuboidal epi.Colliod

High power:

The cell is of square with a central round nucleus stained in purple blue.

The cytoplasm is stained red.

Note that the cells are as tall as they are wide

3. simple columnar epithelium

Material: human intestine

Method: H&E

Slide NO. 1

Low power：

The outline of the villi is a line of the simple columnar epithelium

1

High power ：

The outline of the villi is a line of the columnar cells.

The oval nucleus is close to the base of the cell, stained in blue .

The cytoplasm is stained in red.

Striated bonder Goblet cells

Simple columnal epi.

4. pseudostratified ciliated columnar epi.

Material: Human trachea

Method: H&E

Slide NO. 3

Low power：

The inner surface of the wall is a line of the pseudostratified ciliated columnar epi.

High power：

1.Cilia2.Columnar cell 3. Goblet cell. 4. Spindle cell5.cone cell6.Basement membrane

cilia

Basement membrane

Pseudostratified ciliated columnarPseudostratified ciliated columnar epitheliumepithelium

1

2

3

4

5. Stratified squamous epithelium

Material: human esophagus

Method: H&E

Slide NO. 2

Low power:

The epi. is thick which lines the inner surface of the organ. It consists of many cell layers.

1. stratified squamous epithelium

1

High power:

1.squamous cell

2.polygonal cell

3.basal cell1

23

surface

intermediate

basal

Slide NO. 33

Transitional epithelium

Material: Human urinary bladder

Method: H&E

1.epithelium

1

1

Low magnification:

The epithelium consists of many cell layers .

Middle Magnification :

Think of which functional condition does this specimen belong to ?

2

Middle cells layer

Deep cells layer

Surface cells

domeshaped cells.

Cytoplasm

Nucleolus

Cell

Goblet cell

Striated border

simple columnar epithelium

H&E stain 400 ×

The drawingThe drawing

QUESTIONSQUESTIONS What are the general features of epithelial tissue?1) contain more cells and less extracellular ground

substance2) Polarisaton: ---free outer surface: face the surface of the body or the

lumen of an organ or gland ---basal surface: face underlying connective tissue3)  Avascularity, but innervation: ---no blood vessels ---rich in nerve terminals4) Having functions of protection,secretion, absorptionand sensory reception