what are the four basic tissues in the body?
nervous, muscular, connective, epithelial
where is epithelial tissue found (2)?
covers exterior body surfaces and lines cavities and tubes (anywhere the body comes into contact with the external environment)
what is cytokeratin?
intermediate filament that all epithelium contain. This helps histologists stain epithelium
what are four potential functions of epithelial cells?
protection, transportation, glandular secretions, sensation
what are the three domains of an epithelial cells?
apical domain (faces lumen), basal domain (sits atop basement membrane), lateral domain (between adjacent epithelial cells)
what two features are used to classify epithelial cells?
number of cell layers, morphology of the cells ON THE SURFACE OF THE EPITHELIUM
when determining cell shape, where do you look?
cells on the surface of the epithelium
epithelial cells that are one cell thick are classified as...
epithelial cells that are two or more cells layers thick are classified as...
epithelial cells that are wider than they are tall are classified as...
epithelial cells that are equally wide and tall are classified as...
epithelial cells that are taller than they are wide are classsified as...
what is the function of simple squamous epithelium? where is it seen (4)
fxn: selectively permeable barrier that allows for rapid diffusion Location: respiratory spaces (alveoli), bowman's capsule, endothelium (lines blood vessels), mesothelium (body cavities)
all epithelium rest on what?
a basement membrane
what is the function (3) and location (3) of simple cuboidal epithelium
fxn: protection, absorption, secretion location: small ducts of exocrine glands (pancreas), kidney tubules, thyroid follicles
simple columnar epithelium: function (2), location (3)
Fxn: absorption and secretion Location: stomach, small intestine (and colon), gallbladder (lines most the GI tract)
pseudostratified epithelium: function (3), location (2)
fxn: absorption, secretion, transport location: bronchial tree (ciliated), vas deferens/epididymis
is preudostratified epithelium really stratified at all?
no, all cells rest on BM, their nuclei are just not all on the same level (as seen in simple columnar)
stratified squamous epithelium: fxn, location (4)
fxn: protection location: epidermis of skin, oral cavity, esophagus, vagina
where is keratinized epithelium found? what type of epithelium is it?
stratified squamous epithelium can be keratinized or non-keratinized. keratinized epithelium is on the skin
what is keratin? role?
extra layer of keratin on top of the epithelium that adds protection
stratified cuboidal epithelium: function (2), location (2)
fxn: protection and conduit Location: large ducts of exocrine glands (salivary, mammary, sweat), anorectal jxn
stratified columnar epithelium: fxn (2)? lxn (2)?
Rare in body. functions in protection and conduit. location is large exocrine glands and anorectal jxn
transitional epithelium: appearance, location, fxn, alternate name
appearance: large dome-shaped "umbrella-like" cell on surface Fxn: distensible, protection location: lower urinary tract AKA urothelium
simple squamous epithelium
simple columnar: note nuclei are on the same level
pseudostratified. note nucleus on different levels
stratified squamous: only the top layer counts!!
transitional epithelium (urothelium)