Epithelial Tissue Flashcards
covers body surfaces, lines body cavities, and forms glands; characterized by production of keratin intermediate filaments
epithelia
developmental area that gives rise to epidermis, cornea and lens epithelia of eye, enamel organ and enamel of teeth, anterior pituitary, and inner ear
ectoderm
developmental area that gives rise to the neural tube (CNS): pineal body, posterior pituitary, sensory epithelium of eye, ear and nose; and the neural crest (PNS): ganglia, nerves, glial cells, adrenal medulla, melanocytes, neuroendocrine cells
neuroectoderm
developmental area that gives rise to the epithelium of kidneys and gonads, mesothelium lining pleura, peritoneal, and pericardial cavities, endothelium of blood and lymph vessels, and the adrenal cortex
mesoderm
developmental area that gives rise to epithelium of respiratory system, alimentary epithelium excluding the anal and oral cavity, liver, pancreas, gallbladder, thyroid, parathyroid, thymus, tympanic cavity and Eustachian tubes, transitional epithelium of bladder
endoderm
functions as barrier, semi-permeable membrane, secretion, absorption, transport, and sensation
epithelium
epithelium never penetrated by blood vessels
epithelia avascular
_______ is supported by basement membrane, separates epithelium from underlying connective tissue and blood vessels, relies on diffusion of O2 and nutrients from underlying tissue
epithelium
epithelium that lines cavities that connect with outside world (alimentary, respiratory, urogenital); contains surface epithelium of ectoderm, basement membrane, supporting connective tissue (lamina propria), and sometimes layers of smooth muscle
mucous membrane
epithelium that lines closed body cavities (peritoneal, pleural, or pericardial); consists of epithelial lining, mesothelium, basement membrane, and supporting connective tissue; lacks muscularis mucosae
serous membrane
epithelium that lines blood and lymph vessels; associated with variable numbers of muscle and connective tissue layers or tunics
endothelium
T/F Most epithelial cells have finite lifespan
True
extracellular matrix proteins (external lamina) that provides structural support, scaffolding for growth, differentiation, and migration of cells during embryonic growth and regeneration
basement membrane
major components of ________ include GAG’s, type 4 collagen, and structural glycoproteins (laminin, fibronectin, and entactin)
basement membrane
layer of basement membrane in contact with basal cell membrane
lamina lucida
layer of basement membrane that merges with surrounding tissue
lamina reticularis
layer of basement membrane anchored to underlying connective tissue by microfibrils of type 4 collagen
lamina densa
3 functional types of cell junctions
occluding, adhering, and communicating
located immediately beneath luminal surface of simple columnar epithelia that seals intercellular space and prevents leakage
occluding (tight) junctions
continuous, circumferential band formed around the cell where portions of opposing cell membranes fuse together
zonula occludens
present between endothelial cells in wall of blood vessels that promote extravasation of WBCs
fascia occludens
cell junction that binds cells together and act as anchoring points for cell cytoskeleton
adhering (anchoring) junctions
continuous band characterized by transmembrane glycoproteins called cadherins where the adjacent cell membranes are not fused
zonula adherens
small circular patches (spot welds) located on lateral surface of cell that are associated with attachment plaques containing attachment proteins like desmoplakins, desmogleins, and tonofilaments
macula adherens (desmosomes)
most common type of cell junction
macula adherens (desmosomes)
cell junctions found on basal surface of cell only, anchoring it to basement membrane via integrins that are associated with high mechanical abrasion/shearing forces
hemidesmosomes
a specialized, circumferential, intercellular connection that is a hybrid between adhering and occluding junctions that forms diffusion barrier between cells
junctional complex (terminal bar)
zonula occludens (tight junction), zonula adherens (adherens junction), and macula adherens (desmosomes) comprise the ____________
junctional complex (terminal bar)
focal or regional adherent zones located on lateral border of cell that permit passage of small molecules between adjacent cells and allows transport of information and metabolites between cells
gap (nexus) junctions
short, finger-like cytoplasmic projections that contain actin filaments that extend from cell surface that increase surface area for absorption or secretion
microvilli
network of actin microfilaments at base of microvilli that provide support
terminal web
long microvilli (not cilia) found only in epididymis of males and sensory cells of inner ear that are non-motile and contain actin filaments
stereocilia
long, motile cytoplasmic extensions that posses an axoneme that arise from an individual basal body formed from centrioles; beat in a synchronous rhythm; has rapid, rigid, effective stroke and slower, flexible recovery stroke
cilia
9+2 arrangement of microtubules seen in cilia
axoneme
disorder that causes sterility in males due to non-functional flagella on sperm
Kartagener’s syndrome
heart appears on left side of body due to absence of ciliary activity during embryonic development
Dextrocardia/ situs inversus
disorder due to non-functional cilia on ependymal cells unable to circulate CSF
hydrocephalus
epithelium that is 1 cell layer thick
simple
epithelium that is 2 or more layers thick
stratified
epithelium that looks stratified but isn’t; all cells rest on basement membrane but not all cells extend to epithelial surface
pseudostratified
flattened cells that; width>height
squamous
width=height=depth
cubodial
height>depth
columnar
simple squamous
simple cubodial
simple columnar
stratified squamous
pseudostratified
transitional epithelium
lines most of urinary tract except for parts of urethra; stratified epithelium, modified for distensibility; varies from squamous to cuboidal
transitional epithelium
epithelium linig blood vessels and lymphatics; simple squamous
endothelium
epithelium lining closed body cavities (thoracic, pericardial, and abdominal cavities); simple squamous
mesothelium
endothelium
mesothelium
gland with unbranched ducts (straight or coiled)
simple gland
gland with branched ducts
compound gland
gland that has a tube-like shape (straight or coiled)
tubular
gland that is shaped like a sac or flask
acinar
gland shaped like a tube with a dilated end
tubuloacinar
gland that secretes a watery solution; basophilic acini
serous gland
gland that secretes a thick, viscid secretion that appears clear on an H&E
mucous gland
gland that contains both mucous and serous acini that often include serous demilunes
mixed gland
secrete lipids in form of sebum on skin
sebaceous gland
1: Serous acini
2: Striated ducts
3: Mucous Acini
gland that lact ducts that secrete products directly into bloodstream
endocrine glands
gland that secretes product onto epithelial surface via ducts that contain myoepithelial cells
exocrine glands
Exocrine gland
lie between secretory cells and basement membrane; assit in secretion
myoepithelial cells
specialized unicellular exocrine glands that are located in epithelium and secrete mucous
goblet cells
gland where only the ssecretory product is released
merocrine (eccrine)
gland that secretes membrane-bound vesicles; product acompanied by some cytoplasm, usually lipid products
apocrine
gland where entire cell is secreted
holocrine
1: merocrine
2. apocrine
3. holocrine
4. endocrine
