1.03: Epithelium Flashcards
Tight Junctions
Occluding Juctional complexes
- fuses the outside of adjacent membranes
- most apical of the cell junctions
Adherens Junction
Anchoring Junctions
- inferior to tight junction
- important or later adhesions, connects cytoskeletons
- encircles the cell
Desmosomes
Anchoring Junctions
- provides spot like, localized adhesion b/w epithelial cells
- don’t encircle the cell
Gap junctions
Communicating Junctions
- allows diffusion via hexameric channels called connexons
- dont anchor to cytoskeleton
Hemidesmosomes
Anchoring Junctional complex
- basal surface
- anchors cytoskeleton of cell to basement membrane
What are the 2 layers and types of collagen associated with each layer
- basal lamina: type 4 collagen
- reticular lamina: type 3 collagen
Order of layers of basement membrane
Basal on top, reticular on bottom
skin: arrangement + function
- stratified squamos
- mechanical protection
lungs: arrangement + function
- simple squamos
- diffusion/lubrication
kidney/glands: arrangement + function
- simple cuboidal
- absorption/secretion
bladder: arrangement + function
- transitional
- stretch
glands: arrangement + function
- myoepithelial cells
- contractilility
nasal cavity: arrangement + function
- pseudostratified columnar
- sensation/receptors, rapid regneration + replacement of cells
Surface epithelium function
covers external surfaces, lines hollow organs, body cavities, and ducts
types/location of surface epithelium
- cutaneous membranes
- mucous and serous membranes
- lining of cardiovascular system
glandular epithelium function
forms secretory portions of glands
3 primary germ layers
ectoderm, mesoderm, endoderm
ectoderm forms…..
epidermis, oral cavity, anal canal
mesoderm forms…
mesothelium of body cavities, endothelium of blood vessels, epithelium of kidneys
endoderm forms….
lining of respiratory tract, lining of digestive tract, epithelium of thyroid
simple squamous epithelium specific locations
- endothelium
- endocardium
- mesothelium of body cavities
- bowmans capsule of kidney
- wall of respiratory spaces in lungs
simple cuboidal specific locations
- kidney tubules
- thyroid follicles
- secretory portion of glands
- small ducts of exocrine glands
simple columnar specific locations
- contain goblet cells, microvilli, or cilia
- stomach, small intestine, colon
- gallbladder + fallopian tubes
pseudostratified columnar locations
- abundant with goblet cells
- trachea + nasal cavity
stratified squamous locations
- epidermis
- oral cavity, esophagus
- vagina
stratified cuboidal locations
- sweat gland ducts
- large ducts of exocrine glands
stratified columnar locations
- large ducts of exocrine glands (salivary)
transitional epithelium locations
- renal calyces, ureters, bladder, urethra
merocrine secretion
membrane bound vesicles, exocytosis
apocrine secretion
products bud off and is released with a thin layer of cytoplasm
holocrine secretion
membrane rupture also releasing cell debris
endocrine glands
secrete hormones into blood vessels via connective tissue
paracrine signaling
secretion impacts surrounding cells (blood vessel lining)
autocrine signaling
secretion impacts the same cell
Theca
expanded apical region of goblet cell
simple tubular gland
intestines
simple branched tubular
gastric glands
simple coiled tubular
sweat glands
simple branched acinar
sebaceous glands
compound tubular
Brunner’s glands
Compound acinar
mammary glands
compound tubuloacinar
salivary
inactive mammary glands
mostly ducts
active mammary glands
lobules increase, stroma is less prominent, lactiferous ducts converge at nipple
