Epithelial tissues Flashcards
What are the 2 major categories of epithelia?
Membranous, glandular
What are 2 ways in which membranous epithelia are further described?
- Number of layers (simple, stratified, pseudostratified)
2. Cell shape (squamous, cuboidal, columnar)
What is a simple epithelium?
ONE cell layer thick, resting on a basement membrane. Mononucleated.
Describe simple squamous epithelia.
Single layer of cells that are much flatter than they are tall.
What is mesothelium?
Simple squamous epithelium that covers the outer surface of organs.
What cell type makes up the amnion?
Simple cuboidal
What do intestinal goblet cells do?
Secrete mucin
What are the primary cells of the lining of the gut?
Simple columnar
What are stratified epithelia and how are they named?
Two or more layers of cells, with the deep layers usually different than the surface. **Named for the most superficial layer!
Where do stratified squamous NONkeratinized epithelia exist? What are some examples?
Moist surfaces of the body that require special protection against abrasive forces. e.g. lining of esophagus, parts of oral cavity, epiglottis, vagina, etc.
How do cells move through the stratified squamous epithelium?
Cells are generated in the basal layer of the epithelium and become flattened as they are pushed toward the luminal surface by cells below. They change from columnar basal to squamous.
Do keratinized cells have nuclei?
No! Replaced with keratin
What cells line glands and ducts?
Stratified cuboidal epithelium
What cell type defines respiratory epithelium?
Ciliated pseudostratified epithelium
What makes something pseudostratified?
All cells touch/reside on the basement membrane but reach different heights to that they appear almost multi-layered.
Where do you find transitional epithelia?
Bladder
What cell type is characteristic of transitional epithelia? What defines it?
Binucleated umbrella cells, defined by a chance in appearance when stretched; usually stratified.
What is adluminal?
Toward the lumen
What is abluminal?
Away from the luminal (attached to the underlying surface)
B = base!
What is the basement membrane?
Any interface of epithelia and connective tissue. Connected via integrins
What are 5 common characteristics of epithelia?
- Form surface-parallel sheets
- Sheet and individual cells are polarized
- Cells are tightly apposed to each other
- Avascular
- Dynamic
What is metaplasia?
Epithelia produce progeny that are specialized, but not what is normally found in that location.
What is dysplasia?
Abnormal differentiation results in altered size, shape, and organization of mature cells; may preclude neoplasia.
What is neoplasia?
Cancer. Occurs if cell proliferation is not controlled and results in an abnormal mass of proliferating cells ( a tumor). Benign (non-cancerous, localized) vs malignant (cancerous, metastatic).
What type of fiber can be tissue-specific?
Intermediate fibers
What germ layer makes up the CNS?
Ectoderm
To transport material across and epithelium, cells use ______.
Caveolae
What are basal enfoldings/striations?
Epithelial cells that actively transport something (e.g. sodium) outside of a cell WITHOUT processing (transcellular transport!)
