How to identify transitional epithelium in histological slide

Transitional epithelium is a type of stratified epithelium.

This tissue consists of multiple layers of epithelial cells which are adapt to the degree of distension needed. Example: urinary bladder

 It  lines the organs of the urinary system and is known here as urothelium. 

 Transitional epithelium is made up of three types of cell layers: basal, intermediate, and superficial

 In empty urinary bladder the cells of the superficial layer are cuboidal with a domed apex . 

some time apical cell contain more than one nucleus

in distended bladder apical cells are stretch , flattened and squamous in shape 

 

In empty urinary bladder this epithelium  are 5-6 layers

But during distended bladder they are 3-4 layer

EX: ureter, urinary bladder

 

How to identify stratified columnar epithelium in histological slide

 How to identify stratified columnar epithelium in histological slide 

Stratified columnar epithelium is a rare type of epithelial tissue composed of column-shaped cells

arranged in multiple layers. Usually only 2-3 cells layers are present. 

Basal cells are cuboidal to low columnar in shape 

Apical group of cells are columnar in shape .

** In stratified epithelium name of epithelium is occurred as per shape of apical groups of cells  

Stratified columnar epithelia are found in a variety of locations, including:

·         parts of the conjunctiva of the eye

·         parts of the pharynx

·         anus

·         uterus

·         male urethra and vas deferens

·         lobar ducts in the salivary glands

Embryology

Stratified columnar epithelium is initially present in parts of the gastrointestinal tract in utero before being replaced with other types of epithelium. For example, by 8 weeks, it covers the lining of the stomach

 By 17 weeks, it is replaced by simple columnar epithelium

This is also found in the fetal esophagus

Function

The cells function in secretion  and protection.