2: Epithelium Flashcards
Epithelium
a sheet of cells that line all body surfaces, cavities, and tubular organs
3 embryonic germ layers
ectoderm, endoderm, and mesoderm
Avascular
no blood cells
Apical surface
exposed to the external environment and carries out specific functions
Basal surface
lies on a supporting connective tissue which is separates from the epithelium by a basement membrane
Basal lamina
specialized collagenous fibers that make up the basement membrane
laminin
an adhesive molecule that helps make up the basement membrane
Simple squamous
single layer of flat cells, gases and liquid can diffuse across easily
Endothelium
simple squamous cells that line blood vessels, lymphatics, and the heart
Mesothelium
simple squamous cells that line seous body cavities and outer tubular organs in the abdomen
What cells line the small tubules in the kidney?
simple squamous
Simple cuboidal
single layer of cells where width and height are equal
What do simple cuboidal cells line?
small ducts
Simple columnar
single layer of cells where height is greater than width
What do simple columnar cells line?
much of GI tract due to their secretory and absorptive capability
Pseudostratified columnar
columnar cells that all touch basal lamina, but do not all reach the lumen
Where do pseudostratified cells line?
reproductive and respiratory tracts because they usually have cilia to move particles
Stratified squamous
multiple layers of cells where top layer is flat
Keratinized stratified squamous
surface cells synthesize keratin
Non-keratinized stratified squamous
surface cells are viable (esophagus)
What do stratified cuboidal and columnar cells line?
large ducts
Transitional stratified cells
changes between cuboidal and columnar depending on state of distention
Where are transitional cells found?
urinary tract
T/F: transitional cells all contact basement membrane
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