Histology - Epithelium Flashcards
Extracellular matrix layer between epithelial cells and underlying CT. Carbohydrate base.
Basement membrane
bands encircling the cell, linking adjaent cells together. Resists mechanical separation of cells.
zonula adherens
integrin used as adhesive moleculelinking basal lamina to cytoskeleton.
Cell-Matrix Junctions
do not normally undergo mitosis, however retains ability if organ damaged or needs increase (ex, hepatocytes).
Stable epithelium
bacteria in GI tract that attacks tight junctions and causes ulcers.
Helicobacter pylori
Adheren Junctions (Zonula adherens)
E-cadherin (grey dots at TEM) inserted into intracellular space and fuse together and linked to Actin filaments. Zonula (Belt) all the way around the cell. Resist mechanical separation and maintains sheet-like structure. Found in Epithelium and Cardiac muscles
Microvilli
Short projections of the apical membrane and cytoplasm of lumen w/ associated Glycocalyx. Composed of plasma membrane surrounding Actin Filament Core which is anchored to a terminal web (actin). Forms a brush border (flat top haircut).
Occludin and Claudins
Claudins join in the intercellular space to form Junctional Strands
actin filmamentous core, cross linked to plasma membrane and other actin binding proteins. Anchored to Terminal Web (TW) (also actin).
Microvilli core skeleton
only a few, no mitosis (adult), eg, cells in core of lens, hair cells, inner ear.
Permananet Epithelium
Uncontrolled proliferation of cells (failure of normal regulatory mechanisms)
Neoplasia
3-4 longer than MV, less ‘orderly’. Specialized to move substances along a surface.
Cilia
steady state renewable, replace cells that are ocntinuously lost, with rpesent stem cells. Proliferation is highly regulated (ex: epidermis, epithelium of GI tract, respiratory system, urogential systems)
Labile epithelium
No CAMs, have transmembrane connexons. Aid in cell-cell communication.
Gap junctions
tight junction, barrier to paracellular transport.
Zonula Occuldens
Lateral Folds
Increases surface area through interdigitation of plasma membrane of adjacent cells, aiding in Fluid and Electrolyte transportation via Transcellular pathway.
Focal Adhesion
Integrin proteins linked to basal lamina outside cell and Actin Filaments inside cell. Aids in adhesion and mechanosensitivity.
Adaptor Proteins
Supress proliferation of epithelial cells.
Transcellular transport
Transcellular transportExchange of substances to/from lumen and CT by passing through an epithelial cell. Active process.
associated with aubdant mitochondria that increase surface area for active ion transport.
Basal folds
BL (basal lamina) + RL (reticular lamina) (at TEM level)
BM (at light level)
a carcinoma featuring microscopic glandular-related tissue cytology, tissue architecture, and/or gland-related molecular products, e.g., mucin.
Adenocarcinoma
interact with desmosomes (cell-cell adhesion) and hemidesmosomes (cell-matrix adhesion) via adapter proteins.
Intermediate filaments
problem with adhering type junctions, cells pull apart and space fills with fluid.
blistering
Covers, lines, secretes, absorbs
Epithelium