Epithelium Flashcards
Name the four basic tissues
epithelium, connective, muscle, nerve
Name 5 characteristics of epithelial cells
- cover exterior body surface
- avascular
- line internal cavities
- forms secretory portion of glands
- receptors for special sense
Where is the basement membrane?
between the epithelium and the connective tissue
What is the name of the connective tissue below the basement membrane?
Lamina propria
Does the basement membrane contain cells?
No it is acellular
Name 4 functions of the epithelium
1) Receptors for senses
2) Absorption
3) Secretion
4) Protection/Barrier
RASP
How many domains do epithelial cells have?
3
What are the domains of the epithelium?
Apical domain - exposed to lumen
Lateral domain - in contact with neighboring cells by junctional complexes and adhesion molecules
Basal domain - attached to basement membrane
What creates polarity in the epithelial cells?
Proteins that line the plasma membrane determine polarity (i.e. transmembrane proteins in apical and basal domain)
Name 4 major types of epithelium
Simple
Transitional
Stratified
Pseudostratified
Name 3 shapes that epithelial cells come in
Squamous
Cuboidal
Columnar
Describe simple squamous epithelia and where it is found
- one layer of cells that are wider than they are tall
- thinnest tissue in body
- lines blood and lymphatic vessels
- Nucleus always bulges into lumen
Where are simple squamous epithelia found?
Blood and lymphatic vessels (ex. bowman’s capsule in kidney, respiratory spaces in lungs)
Why is simple squamous epithelia ideal as a thin tissue?
Allows for transfer of material from lumen across epithelium and facilitates diffusion of gases and small molecules
Simple squamous epithelia that covers the closed cavities in the body is called what?
Mesothelium
Simple squamous epithelia that lines the atria and ventricles of the heart is called what?
Endocardium
Simple squamous epithelia that lines the blood vessels is called what?
Endothelium
Why is it important for the simple squamous epithelium to be the same direction as flow of blood?
To maintain health of blood vessels because points where blood vessels are going to branch
Describe simple cuboidal epithelia
- Width of cell similar to height
- Eosinophilic
- they are basic
Where are simple cuboidal epithelia found?
Ducts and Tubules (Kidney tubules, small ducts of exocrine and endocrine glands etc. )
What is the function of simple cuboidal epithelium?
Absorbing and secreting material into ducts
Describe simple columnar epithelium.
- shaped like a column
- nuclei are lined up in the basal portion of the cells
- sometimes apical domain contains specializations (microvillus/cilia)
Where are simple columnar epithelium found?
All through out GI tract such as small intestine, stomach lining, etc.
What is the function of simple columnar epithelium?
- Absorbs nutrients
- Protection
- Impermeable barrier to bacteria