Epithelia Flashcards
What are the 4 ways of classifying epithelia?
Shape of cells
Number of layers of cells
Combination of both the shape of cells and the numbers of layers of cells
Function
What is epithelia?
They are cells which line all surfaces of the body, tubes and cavities. They are also responsible for the formation of the boundary between fluid compartments in the body.
What are carcinomas?
Tumors which arise from epithelial cells
What are the different domains in the shape of epithelial cells?
columnar
cuboidal
squamous
What are the different domains in the number of layers of epithelial cells?
simple and stratified
What are the characteristics of simple epithelia?
One layer of cells
all cells are both in contact with the basement membrane and the lumen
located in areas where diffusion/absorption/secretion take place, the thinner the epithelium the faster those processes take place
What are the characteristics of stratified epithelia?
Many layers of cells
basal cells are in contact with basement membrane
apical cells are in contact with lumen
found in areas where there is a need for protection
the thicker the epithelium, the greater the protection against abrasion/infection/caustic content
Example of a location where simple squamous epithelia is found?
Lining of blood vessels, lymphatics and body cavities
Example of a location where simple cuboidal epithelia is found?
Kidney tubules
Example of a location where stratified squamous epithelia is found?
Skin
Example of a location where stratified cuboidal epithelia is found?
Reproductive system
Example of a location where transitional epithelia is found?
Bladder
What are the characteristics of epithelia which carry out exchange functions?
simple epithelia, flattened, have pores between cells which permit easy passage of molecules (eg. lungs and blood vessels)
What are the characteristics of epithelia which carry out transporting functions?
simple epithelia, are cuboidal or columnar, have tight junctions which limit movement between cells (eg. intestine and kidney)
What are the characteristics of epithelia which carry out ciliated functions?
simple epithelia, cubiodal or columnar, have cilia which move fluid across the surface (eg. trachea and female reproductive tract)