Epithelial Tissues Flashcards
What is the function of epithelial tissues?
Lines all body surfaces including skin and tubes and cavities. Barrier function between different environments
What is the outer layer of the skin called?
The epidermis
How are epithelial cells arranged?
Continues sheets of tightly bound cells
What does the arrangement of epithelial cells ensure?
protection against microbial invasion and provide opportunity to regulate movement of substances
What is the polarity of epithelial cells?
Polarised
What are the 3 layers of epithelial cells?
Apical surface, lateral surfaces and basal surface.
What do tight junctions do?
Create an impermeable seal between adjacent cells and prevents water leakage
What are desmosomes and what do they do?
Strong junctions. Anchor adjacent cells together. Ensure epithelial tissues can stretch and maintain contact
Other then the main function of epithelial tissues what other functions are there/
Physical protection, diffusion, absorption and secretion
How can epithelial tissue structure differ?
Shape of cells, number of cell layers, apical specialisations
What are the 3 shapes of epithelial cell?
Squamous, cuboidal and columnar
What are the two different layers of cells?
Simple (single) and stratified (2+ layers)
What apical specialisations are there?
Microvilli, cilia and keratin
What do microvilli do?
increase apical surface area
What do cilia do?
Movement of particular matter
What is keratin?
Strong and protective apical layer
What do simple squamous cells do and where are they located?
Lines surfaces involved in passive diffusion and is located in the lungs (alveoli) and capillaries (endothelium)
What do simple cuboidal cells do and where are they located?
Lines small ducts and tubules involved in secretion/absorption and are located in the collecting tubules of the kidney and small ducts of the salivary glands
What do simple columnar cells do and where are they located?
Line absorptive surfaces and are located in the small intestine
What does ciliated simple columnar epithelium do and where is it located?
ciliary action facilitates transport of ovum from ovary to uterus and is located in the female reproductive tract
What do ciliated pseudostratified columnar epithelium do and where are they located?
ciliary action propels surface layer of mucous containing trapped particles towards the pharynx and is located in the airways of respiratory system
What are goblet cells, what do they do and where are the located?
Modified columnar epithelial cells. Synthesis and secrete mucous. Scattered throughout simple columnar epithelium e.g. respiratory and gastrointestinal
What is the function of stratified epithelia?
Protection from mechanical abrasion.
Where do cells mature and what do they do once matured?
In the basal layer from continuously dividing stem cells. They gradually migrate to the surface and are shed as anucleate squames
What does keratin do?
Enhances resistance to physical stress
What is keratin?
Formation of tough, non-living surface layer
What do stratified cuboidal cells do and where are they located?
They are secretory cells and are located in some secretory ducts and glands
What do stratified columnar cells do and where are they located?
They are secretory and protective and are located in the male urethra and line some glands
What does transitional epithelium do and where is it located?
Allows for expansion and stretch and is only found in the bladder
What is ulceration?
A break in the continuity of epithelium
What is oral squamous cell carcinoma?
The dysplastic squamous cells of the epithelial lining have degraded the basement membrane to invade the underlying tissues. It destroys and invades adjacent tissues
What is a carcinoma?
A malignant tumour arising from the epithelial tissue
