Epithelial Cells And Tissues Flashcards
What are epithelial cells?
Cells which form continuous layers which line surfaces and separate tissue compartments
What is the importance of having well organized and stable cell-cell junctions?
means the cells are not leaky - fully cohesive
What is the importance of epithelial cells?
Separating tissue compartments or lining the surfaces of a tissue
What two features of epithelial cells are used to classify them?
- Shape
2. Size
What do squamous cells look like?
Flattened , plate shaped
What do columnar epithelium cells look like?
Arranged in columns
What do cuboidal epithelium look like?
Cube-like
What are the three classifications of shape in epithelial cells?
Squamous, Columnar and Cuboidal
How many layers do simple epithelium have?
one layer
What is he name given to describe the multilayered appearance of epithelium?
Stratified
Where are simple squamous epithelium found?
Found in lung alveolar, epithelium, mesothelium and endothelium
What is the purpose of simple squamous epithelium?
form a thin epithelium that allows gas exchange to occur
Which surfaces are simple columnar epithelium found in?
Surfaces involved in absorption and secretion of molecules eg enterocytes lining the gut or surfaces involved in the uptake or breakdown of product of digestion
What are the two types of stratified squamous epithelium?
Keratinizing and Non-keratinizing
What is meant by non-keratinizing epithelium?
epithelial cells which do no undergo keratinisation and so retain their nuclei and organelles
Where are non-keratinizing stratified squamous epithelium found?
epithelium lining the mouth, oesophagus, anus, cervix and vagina
What is meant by keratinizing epihelium?
Epithelial cells which produce keratin
What happens to cells after they produce keratin?
The cells produce keratin and then die - becomes much stronger surfaces e epidermis - lose their organelles and nuclei
What is the benefit of the keratinizing ability of some stratified squamous epithelium?
can form thick layers which are useful for protecting underlying tissues for various physical and chemical insults eg heat, cold, solvents (alcohol) and abrasion
What is meant by pseudo-stratified epithelium?
This epithelium appears to be multi-layered but on close examination, all th surface cells have contact with the basal laminae
Where are pseudo-stratified epithelium found?
Airway (trachea and bronchi) epithelium, various ducts in the urinary and reproductive tracts
What are tissues made up from?
Cells, extracellular matrix and fluid
What organises tissues into discrete domains?
Junctions
Where is the apical domain found?
At the lumenal surface