Epithelium(Practical)

Hanan Jafar BDS.MSc.PhD

Types of Simple Epithelium

Simple

squamous

Simple

cuboidal

Simple

columnar

Pseudostratified

columnar

Mesothelium Ciliated Ciliated

Endothelium Non Ciliated

(Microvilli)

With stereocilia

Simple Squamous Epithelium

Location: endothelium, mesothelium, lung alveoli

Functions of Simple Squamous Epithelium

Permits bidirectional movement of gases, fluids and nutrients from the free surface to underlying tissue

Naming of the simple squamous epithelium

depends on the location:

• Endothelium is the lining of the blood vessels,

lymph vessels and the heart.

• Mesothelium is the epithelium forming serous

membrane lining internal body cavities:

Peritoneum, Pleura and Pericardium.

Endothelium

Endothelium

Mesothelium

Mesothelium

Mesothelium

Endothelium

Simple Cuboidal

Location

Small ducts of certain glands (pancreas & salivary), kidney tubules

Simple Cuboidal Epithelium

• Structure

– Single layer of cube shaped cells

• Function

– Secretion and absorption.

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Simple cuboidal

Simple squamous

Simple Columnar Epithelium

Microvilli

Location

Small intestine, Stomach, Gall

bladder, fallopian tube

Simple Columnar Epithelium

With microvilli With cilia

Function of Simple Columnar Epithelium

Engaged in the protection of wet surfaces, absorption and secretion.

When ciliated (Fallopian tube), it helps in movement of fluid in the female genital tract.

20

Goblet Cells

Pseudostratified Columnar Epithelium

Location: Respiratory tract (trachea and bronchi)

Pseudostratified columnar

Epithelium• Structure

– Irregularly shaped cells with nuclei at different levels – appear stratified, but aren’t.

– All cells reach basement membrane

• Function

– Absorption and Secretion

– It entraps foreign particles in the respiratory tract.

Respiratory Epithelium

http://www.google.com/url?sa=i&rct=j&q=&esrc=s&frm=1&source=images&cd=&cad=rja&uact=8&ved=0CAcQjRw&url=http://www.ask.com/science/goblet-cells-found-465ea1e93902c069&ei=hXPkVMfKAsbuPLmMgfgO&bvm=bv.85970519,d.d24&psig=AFQjCNHNDnF3MiMjHqhL4794aESagwiP-A&ust=1424344091095348

Types of Stratified Epithelium

Stratified Squamous

Keratinized

Non Keratinized

Stratified cuboidal

Stratified columnar

Transitional epithelium

Stratified Squamous Non keratinized Epithelium

Location: Oral cavity, Esophagus, Anal canal, Vagina

Stratified Squamous Keratinized Epithelium

Location: Epidermis of skin

Stratified Cuboidal Epithelium

Location : Larger ducts of certain exocrine glands

Stratified Columnar Epithelium

Location : Conjunctiva, larger ducts

Transitional Epithelium

Location: Urinary tract (urinary bladder and ureters)

Stretched (distended

organ)

Fluid pressure

Unstretched (empty

organ)

Superficial layer of

dome/umbrella-shaped cells

Transitional Epithelium

Function

- Allows stretching (change size)

- Protection

Binucleated cell

Dome-shaped cells

Features of Apical surface

of Epithelium

Microvilli/ LM

Microvilli/ TEM

Cilia/ LM

Cilia/ TEM

9 + 2

Cilia

Microvilli

Scanning EM

Stereocilia