MCM Epithelium Flashcards
Simple squamous is located _______.
- Blood vessels (endothelium)
- body cavities (mesothelium)
- Bowman’s capsule
- alveoli
Simple cuboidal function & location?
- function: protective, secretory, and absorptive
- location: Gland ducts, kidney tubules
Simple columnar - long, _____ nucleus. Location?
- ovoid
- Lining of intestine, stomach, female reproductive system, etc
- Microvilli has_____ and is located _____.
- glycocalyx
- Striated border = microvilli + glycocalyx
Increases surface area for absorption/secretion
Cilia function and location.
- fxn: Transport matter along cell surface
- location: Found on columnar cells
Location of nonkeratinized epithelium?
Lining moist cavities (oral cavity, esophagus, vagina, anal canal)
Stratified cuboidal is found _____.
sweat glands
Stratified columnar
conjunctiva,
lining ducts of large glands
Where is Where is transitional epithelium found?
bladder
ureter
urethra
cells are binucleate (unique to this epithelium)
Describe the transitional epithelium when the bladder is full vs. empty.
full: apical cells flattened (“shield”)
empty: apical cells rounded & dome-like
Pseudostratified columnar epithelium location & specializations?
- respiratory tract & male reproductive system
- stereocilia (surface of epididymal epithelium)
Single layer attached to basal lamina (Nuclei arrangement → appearance of 2-3 cell layers)
Location of Glandular epithelium?
penetrate into the underlying connective tissue (exocrine glands)
Describe the major components of the epithelial basal lamina.
- Type IV collagen, laminin 5, fibronectin, hemidesmosomes
- Laminin – attaches BL to the epithelium, has binding sites for integrin/collagen IV
Acellular dense fibrous sheet interposed between the basal epithelial cell layer and the underlying connective tissue
What is the importance of the epithelial basal lamina?
- Forms barrier between epithelium and underlying connective tissue.
- Firm, yet flexible support for overlying epithelium.
Name the epithelia in the grey box (simple).
- squamous
- cuboidal
- columnar
Name the epithelia in the pink box (stratified).
- squamous
- cuboidal
- columnar
(same shapes as simple epithelia)
Name the epithelia in the blue box (simple).
- pseudostratified
- transitional
Microvilli are Composed of _______.
villin, actin filament, myosin I, terminal web, & intermediate filaments
What is the name of microvilli + glycocalyx? Where are they located?
- Brush or striated border.
- Brush: intestine
- Striated: Kidney
Define axoneme & its composition.
the microtubule based cytoskeleton of cilia
contains dynein (cytoskeleton motor protein that “drives the beat” of cilia, transforming the chemical energy of ATP into mechanical work)
Define lateral surface folding.
increasing surface area or cell/tissue attachment
Involved in fluid transport (kidney tubules)
Name the three intercellular junctions.
- Junctional complex
- Hemidesmosomes
- Gap junctions
(Junctional complex includes zonula occludens, zonula adherens, macula adherens/spot desmosomes)
What is the function of the zona occludens?
- Help tie the cell together via fused plasma membranes
- Prevents water-soluble molecules from passing between cells
(TEM: quilt-like pattern; AKA “tight junction”)
What are Zonula adherens (AKA “belt desmosomes”)? Where are they located?
- Transmembrane linker proteins - E-cadherin, Actin filament, vinculin and caterin
- Located basal to the TJ, holding adjacent cells together, completely encircle the cell
(NOT to be confused w/“spot desmosomes”/macula adherens which are ALSO a component of the junctional complex).
Define Macula adherens (AKA “spot desmosomes”) function and location.
- Location: Intermediate filaments, desmocollin and desmoglein. Located below belt desmosomes, distributed along lateral cell membranes, disk-shaped
- Function: Help to distribute shearing force
(NOT to be confused with “belt desmosomes”/zonula adherens, which are also part of the junctional complex)
Define Hemidesmosomes.
- Extracellular portions of linker proteins
- Bind to laminin and collagen IV of basal lamina
Do not confuse with “spot desmosomes”/macula adherens or “belt desmosomes”/zonula adherens, both of which are part of the junctional complex)
Define gap junctions.
Six subunits, dumbbell-shaped, 1 connexon consist of 6 connexins. Makes a channel for cells to communicate through.
(Also allows movement of molecules like cAMP, ions & hormones.)
