Epithelial Tissue Organizational Types

There are eight different types of epithelial tissues. They include simple squamous, simple cuboidal, simple columnar, pseudostratifled columnar, stratified squamous, stratified cuboidal, stratified columnar, and transitional. 

Simple Squamous

Simple Quarmos is a single layer of flattened cells with disc shaped nuclei and sparse cytoplasm.

Functions: Diffusion and filteration- provide a slick friction reducing lining in lymphatic and cardiovascular systems. 


Examples: kidney, glomeruli, lining of heart, blood vessels, lymphatic vessels, serosae. 

Simple Cuboidal

Simple Cuboidal epithelium is a single layer 

single layer of tall cells with oval nuclei: many contain cilia

Goblet cells are often found in this layer
function in absorption and secretion
nonciliateted type line digestive tract and gallbladder
ciliated type line small bronchi, uterine tubes, and some regions of the uterus
cilia help move substances through internal passageways


Function: absorption: secretion of mucus, enzymes and other substances

Simple Columnar

single layer of tall cells with oval nuclei: many contain cili
-goblet cells are often found in this layer
-function in absorption and secretion
-nonciliated type line digestive tract and gallbladder
-ciliated type line small bronchi, uterine tubes, and some regions of the uterus
cilia help move substances through internal passageways
Function: absorption: secretion of mucus, enzymes and other substances

Pseudostratified Columnar Epithelium

single layer of cells with different heights; some do not reach the free surface
nuclei are seen at different layers
function in secretion and propulsion of mucus
present in the male sperm carrying ducts (nonciliated) and trachea (ciliated)
Function: secrection: particularly of mucus by ciliary action

Stratified Squamous Epithelium

Thick membrane composed of several layers of cells
Function in protection of underlying areas subjected to abrasion
Forms the external part of the skin's epidermis (kertinized cells) and linings of the esophagus, mouth, and vagina (nonkeratinized cells)

Function: protects underlying tissues in areas subjected to abrasion

Stratified Cuboidal and Columnar

quite rare in the body

-found in some sweat and mammary glands
-typically two cell layers thick

Stratified Columnar

limited distribution in the body
-found in the the pharynx, male urethra, and lining some glandular ducts
-also occurs at transition areas between two other types of epithelia

Transitional

several cell layers, basal cells are cuboidal, surface cells are dome shaped.
-stretches to permit the distention of the urinary bladder
-lines the urinary bladder, ureters, and part of the urethra
Function: stretches readily and permits distention of urinary organ by contained urine