CTB1 Flashcards
lamina lucida
right above basement membrane-has adhesive glycoproteins like integrins connecting it to basal cell membrane
lamina densa
top part of basement membrane has type 4 collagen
reticular lamina
bottom part of basement membrane. connect to connective tissue below. type 3 collagen
Cilia
hairlike extensions come off apical surface into lumen. motile due to dynein motor molecule connected to microtubule doublet. Dynein cleaves ATP. seen in respiratory system, tails of sperm
Microvilli
absorptive properties, increase surface area-seen in small intestine, kidney. core of actin that goes into horizontal actin terminal web below. villin anchors at top, nonmotile
stereocilia
unusually long microvilli. only found in epididymis (male reproductive tract, ducts deferent (male repro) inner ear (not male repro)
Gland secretions
down growths of epithelial tissue. exocrine have ducts, endocrine don’t. Mucous (thick and sticky) serous (thin and watery). goblet cells are unicellular glands and do not have duct system
cytoskeleton
microfilaments, intermediate filaments, microtubules
actin microfilaments
core of microvilli, network that determines cell shape (terminal web) cell motility by polymerizing, contractile ring for cell division(with myosin) THIN
intermediate filaments
stabile (non-motile) elements. provide support. link to intercellular junctions so cells don’t rupture when stretched. prominent in keratin and glial cells. thicker than actin, thinner than microtubules
microtubules
tread milling, tracks for movement of organelles in cytoplasm. arise from centrosome near nucleus (centrosome is 2 centrioles=microtubule organizing center) work with kinesis and dynein
Tight junction/occluding junction
zonula occludens. seals gap between epithelial cells. fence between apical and basolateral surfaces. made of claudin and occludin proteins which are linked to ZO proteins, which are linked to actin=helps with polarity
adherens junction
zonula adherens connects actin filament bundle in one cell with next, linked to actin by cadherin adhesion molecules
desmosome
macula adherent. connects intermediate filaments in one cell with next. linked by cadherin adhesion molecules. spots not bands
gap junction
allows passage of water soluble molecules, ions, second messages (like CAMP) via connexon channels (connexin proteins forming pore)
hemidesmosome
anchors intermediate filaments in cell to extracellular matrix. linked with integrins (NOT CADHERINS)
actin-linked cell-matrix adhesion
focal adhesions. linked with integrin. anchors actin in cell to extracellular matrix
agonist drugs
mimic natural agonists by binding to a receptor and switching it on (drugs often have more significant response than natural agonists)
antagonists
“blockers” bind to cell’s receptors and block access from agonists in body
Ri, Ra
Receptor in inactive and active conformation. Ra without ligand is constitutive activity
steroid receptor
only cytoplasmic receptor. lipid soluble chemical (like a steroid hormone) crosses plasma membrane and binds intracellular receptor. Can then go into nucleus to stimulate transcription This uptake into the nucleus is facilitated by nuclear localization signal (NLS) found in the hinge region of the receptor. This region of the receptor is covered up by heat shock proteins (HSPs) which bind the receptor until the hormone is present. Upon binding by the hormone the receptor undergoes a conformational change releasing the HSP, and the receptor together with the bound hormone enter the nucleus to act upon transcription. so steroid hormones alter synthesis of proteins
cytokine receptors
signal binds extracellular domain. receptor dimerizes which STATS bind receptor, phosphorylated by JAKs, dimerize and go to nucleus–> regulate transcription
Enzyme-linked receptors
ex: epidermal growth factor. ligand binds EC domain which causes receptor to go into dimeric state activates cytoplasmic tyrosine kinase. this receptor is exploited in cancer! big cancer drug target
Ion Channel
ligand binds and trans membrane ion channel opens. ex: neurotransmitters ex: nicotinic acetylcholine receptor. often many subunits
G protein coupled receptor
increase [ ] of intracellular second messengers. 7-trans membrane receptors . N-(start) terminal extracellular, C (end) -terminal intracellular
simple squamous
single layer flat cells . thinness is essential for gas exchange. line blood vessels (endothelium) body cavities (mesothelium)
simple cuboidal
single layer. tall=wide=deep. FOCUS ON SEALING sealing, transport, absorption, secretory. collecting tubules of kidney, liver, endocrine glands
simple columnar
single layer, taller than wide. sealing, transport, absorptive, secretory. intestine, endocrine, exocrine, proximal tubules of kidney
stratified squamous
multiple layers. basal layer is cuboidal, middle is flat, 2-3 most apical layers are squamous. strong and protect from abrasion. skin, digestive tract, esophagus, vocal chords, vagina
stratified cuboidal
many cuboidal layers. rare. larger ducts of some exocrine glands.
stratified columnar
LARGEST ducts of exocrine glands, anorectal junction
pseudo stratified columnar
all cells touch basal lamina. some extend to lumen. respiratory epithelium, ductus epididymis in male reproductive system
transitional
larger cuboidal on apical, smaller on basal, can accommodate TREMENDOUS stretching-bladder, ureters, upper urethra.
