Epithelial Flashcards
What are the four types of tissues?
Epithelia
Connective
Muscle
Nervous
Three primary germ layers:
ectoderm
mesoderm
endoderm
General features of epithelia
-little extracellular material
-closely packed cells with specialized junctions
-avascular
-innervated
-apical surface exposed to body or organ cavity
-basal surface attached to basement membrane
The process where one cell type changes into a different one:
Metaplasia
What are carcinomas?
Tumors that arise from surface epithelia
What are adenocarcinomas?
Tumors that arise from glands
Functions of epithelia
-prevention of desiccation
-protection
-filtration
-secretion
-absorption
-sensory reception
Epithelium that lines cavities that connect to the outer world
muscous membrane
Layers of muscous membrane
-ectoderm (endoderm)
-basement membrane
-connective tissue (lamina propria)
-smooth muscle (muscularis mucosae)
epithelium that lines closed body cavities
serous membrane
Layers of serous membrane
-epithelial lining
-mesothelium
-basement membrane
-connective tissue
Four types of apical specialization
-microvilli
-sterocilia
-cilia
-flagella
Microvilli
surface specialization to increase cell surface area for absorption or secretion
What is the terminal web?
In the basement membrane that anchor the microvilli onto the cell
-made of cytokeratin filaments
Stereocilia
very long, non-motile microvilli
-rigid due to core of actin filament
-absorption and secretion
Cilia
-mobile, hair-like projections specialized for coordinated movement
-extension of cytoskeleton
-movement of fluids and particulate matter
axoneme
core of microtubules
(9+2 doublets)
anchored by basal body
Immotile ciliary syndrome
-genetic defect that causes uncoordinated or absent cilia
-recurrent/severe chest infection
-infertility
-hydrocephalus
Flagella
spermy
lateral surface specializations
-tight junctions
-adhering junctions
-desmosomes
-gap junctions (connexons)
Tight junction
fluid tight seals that do not allow anything in the cell or around that part of lateral portion
-present
Adherens junctions
fastens cell to one another
-beneath tight junctions
- dense plagues of myosin, tropomyosin, and vinculin
-integrins are also involved