Epithelial Tissues Flashcards
How are cells held together?
By adhesions/junctions
What are the 4 tissue types?
- Connective tissue
- Nervous tissue
- Muscle
- Epithelial
What to epithelial cells bind to via adhesions/cell junctions?
Themselves and the basement membrane
What makes the basement membrane?
Epithelial cells and connective tissue
What germ layer is epithelial derived from?
All three germ layers
What are the three surfaces of an epithelialcell?
- Free apical surface
- Basal surface
- Lateral surface
What is on the free apical surface of the epithelial cell?
Lumens of ducts and cavities
What is on the lateral surface of an epithelial cell?
Attachments to other epithelial cells including tight juntions and gap juntions
What is on the basal surface of an epithelial cell?
Attachments to the basal membrane
What are three specialisations some free apical surfaces of epithelial cells can have?
- Microvilli
- Stereocillia
- Cilia
What are microvilli?
Cytoplasmic protusions which increase the surface area
What are stereocilia?
Long versions of microvilli but are limited in distrubutuion and non-mobile
What are cilia?
Motile hair-like protusions that beat together
Where are cilia found?
In respiratory epithelial and in the fallopian tubes
What reduces cillia movement?
Smoking
What are specilisations that can occur on the basolateral surfaces of the epithelial cells?
Junctions
What are the functions of the junctions on the basolateral membrane?
They allow attaching cell together and exchanging of information and metabolities
What are the three types of jucntions sometimes seen on basolateral surfaces of epithelial cells?
- Tight junctions
- Anchoring junctions
- Gap junctions
What is the functions of tight junctions?
Seal cells together
What is apical part of the lateral domain of the tight junction that fuses two cells together called?
The zona occuldens
What is the function of anchoring junctions?
Mechanically attachs cells together
What are two components of anchoring junctions?
Desmosomes and hemidesmosomes
What is another name for desmosomes?
Zona adhrens
Where are desomosomes found?
The lateral domain
Where are hemidesomosomes dound?
The basal domain
What are gap junctions?
A passage of chemical/electrical signals between cells
What are the three ways to classify epithelial?
- Number of layers
- Shape of cells
- Specilisations
What are the three categories when cateogrising epithelial under number of cells?
- Simple
- Stratified
- Pseduostratified
What are the four categories when epithalial is classified by cell shape?
- Squamous
- Cuboidal
- Columnar
- Transitional
Where is simple squamous epithelial found?
Blood vessels, heart and alveoi
What is the function of simple squamous epithelial?
Diffusion, absorption, secretion
Where is simple cuboidal epithelial found?
In the kidneys, glands, bronchioles
Where is stratified squamous epithelia found?
Cornea, oral cavity, oesophagus, vagina, anus
What kind of epithelial is found in skin
Stratified keratinized epithlial
What is the difference between keratinized and non-keratinized epithelia
nonkertainized is moist and keratinized are dead cells filled with keratin
What kind of epithelium is rare?
Stratified cuboidal
Where do you find stratidied columnar epithelium?
Mammary glands, larynx, male urethra
Where do you find pseduostratified columnar epithelium?
Nose, pharynx, trachea, bronchi, lungs - synthesis and secrete mucous
Where do you find transitional epithelial?
Urinary bladder, kidney, urethra, uterers - where expansion occurs
