Histology - Epithelium Flashcards

proteins located on the cell surface involved in binding with other cells or with the extracellular matrix (ECM) in the process called cell adhesion.

types of large macromolecular assemblies through which both mechanical force and regulatory signals are transmitted that serve as the mechanical linkages to the ECM, at sites of integrin binding and clustering.

only a few, no mitosis (adult), eg, cells in core of lens, hair cells, inner ear.

Exchange of small solutes, ions, and water to/from lumen and CT by pasing netween lateral domains. Passive provess.

BL (basal lamina) + RL (reticular lamina) (at TEM level)

Uncontrolled proliferation of cells (failure of normal regulatory mechanisms)

a benign tumor of epithelial tissue with glandular origin, glandular characteristics, or both.

Epithelial cells adjacent to the wound site divide, giving rise to new epithelial cells. The new epithelial cells detach and migrate laterally along the remnants of the basal lamina that are still present.

short, finger-like projections of the apical plasma membrane & cytoplasm into the lumen. Very uniform and itghly packed. Increase SA for absorption (and secretion).

3-4 longer than MV, less ‘orderly’. Specialized to move substances along a surface.

tight junction, barrier to paracellular transport.

Exchange of substances to/from lumen and CT by passing through an epithelial cell. Active process.

rows of transmembrane proteins from adjacent cells that appear as ridges or stitches that act as a barrier to paracellular transport pathway.

interact with desmosomes (cell-cell adhesion) and hemidesmosomes (cell-matrix adhesion) via adapter proteins.

Supress proliferation of epithelial cells.

Apical specilization that establishes extracellular microenvironments at membrane surface. Functions: metabolism, cell regocnition, receptor sites etc. Composed of: glycoproteins and glycolipids.

Special arrangement of microtubules. 9 outer doublets, and 2 central singlets. Abbreviated “9+2”. Anchored into the basal body.

Exchange of small solutes, ions, and water between lumen and connective tissue between the lateral domains. Also allows movement of White blood cells into the Connective tissue

join in the intercellular space to form Junctional Strands

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

Extracellular matrix layer between epithelial cells and underlying CT. Carbohydrate base.

steady state renewable, replace cells that are continuously lost. Proliferation is highly regulated (ex: epidermis, epithelium of GI tract, respiratory system, urogential systems)

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).

Weave back and forth through each cell’s plasma membrane several times

a belt like intercellular junction located between adjacent lateral domains immediately "above" the adherens junction. No CAMs, connected by transmembrane proteins. Help define functional domains (apical-basolateral) - establishing polarity and limit paracellular transport.

bacteria in GI tract that attacks tight junctions and causes ulcers.

a carcinoma featuring microscopic glandular-related tissue cytology, tissue architecture, and/or gland-related molecular products, e.g., mucin.

9 triplets

Covers, lines, secretes, absorbs

Integrin proteins linked to basal lamina outside cell and Actin Filaments inside cell. Aids in adhesion and mechanosensitivity.

actin filmamentous core, cross linked to plasma membrane and other actin binding proteins. Anchored to Terminal Web (TW) (also actin).

Hemidesmosomes, Focal Adhesions

localized spot-like adhesions randomly arranged on the lateral sides of plasma membranes. help to resist shearing forces and are found in simple and stratified squamous epithelium. 'velcro dots'

Interdigitations of plasma membrane of adjacent cell lateral comains located below levelk of the junctional complex that increases surface area for interlocking cells and fluid and electrolyte transport via transcellular pathway.

Transmembrane proteins (Occludins and Clausind) weaved back and forth through both cell’s plasma membrane several times that blocks molecular movement between intercellular space. Wrap around cell like a belt. Establishes polarity in cell.

No CAMs, have transmembrane connexons. Aid in cell-cell communication.

integrin used as adhesive moleculelinking basal lamina to cytoskeleton

occludin and claudins that weave through each cell's plasma membrane and extend into ICS.

Formation of cell/tissue masses as the result of the proliferation of neoplastic cells.

Directly Contacts Luminal Contents or External Area

orderly series of 3 junctions, tight junction, adherens junction (ZA), desmosome (D) - terminal bar at light level.

influecne lots of process that occur within cell, one is suppress proliferation (contact inhibition).

a layer of extracellular matrix secreted by the epithelial cells, on which the epithelium sits. Functions: attachment epithelium to CT, regulation/filtration: exchange b/w E + CT, scaffolding (for regeneration).

problem with adhering type junctions, cells pull apart and space fills with fluid.

Loss of adaptor proteins causes epithelial cellad and stem cells adjacent ot wound to proliferate. New epithelial cells detach and migrate along basement membrane.

Increase surface area for mainly absorption and secretion between lumen/external environment

zonula adherens, intermediate junction, or "belle desmosome"

directly contacts the luminal contecnts or external environment. Site of absorption and secretion.

Adheren Junctions (Zonula adherens), Desmosome (Macula adheren)

Strong abrasionand sheering disrupts Focal Adhesions causing separation of epithelial cells from connective tissue and fluid accumulation.

bands encircling the cell, linking adjaent cells together. Resists mechanical separation of cells.

Increases surface area through interdigitation of plasma membrane of adjacent cells, aiding in Fluid and Electrolyte transportation via Transcellular pathway.

a cell junction whose cytoplasmic face is linked to the actin cytoskeleton.

a type of cancer that develops from epithelial cells.

Long projections used for movement of substances and cells, synchronized movement. Less organized, 9+2 arrangement of microtubules.

Integrin proteins attached to Basal lamina outside cell and attachment plaque inside cell. Keratin intermediate filaments strengthen them by adhering to attachment plaque. Resists abrasion, sheering, and tearing forces between Epithelial Cells and Basal Lamina. Strong attachment between epithelial cell and basal lamina.

a type of connective tissue that has a network of reticular fibers, made of type III collagen and only in this lamina are they dominant. Have anchoring fibers and plaques (loops). Thickness varies with frictional force applied to overlying Epi.

do not normally undergo mitosis, however retains ability if organ damaged or needs increase (ex, hepatocytes).

associated with aubdant mitochondria that increase surface area for active ion transport.

Desmosome Cadherin (CAM) insert into intercellular space and overlap each other, inserted into attachment plaque inside cell. Strengthened by keratin intermediate filaments.

small stud- or rivet-like structures on the inner basal surface of keratinocytes in the epidermis of skin that attach one cell to the extracellular matrix.

is an assembly of six proteins that can be a part of a gap junction channel between the cytoplasm of two adjacent cells. Two come together to complete intercellular gap junction channel.