Epithelial Tissues Flashcards
Layers of cells covering internal or external surfaces
Epithelia
Structures that produce secretions
Glands
Characteristics of Epithelia
- Cellularity (cell junctions)
- Polarity (apical and basal surfaces)
- Attachment (basement membrane of basal lamina)
- Avascularity
- Regeneration
Cells arranged in continuous sheets,in either single or multiple layers
Polarity (apical and basal surfaces)
Functions of epithelial tissue
- Provide physical protection
- Control permeability
- Provide sensation
- Produce specialized secretions (glandular epithelium)
Specializations of epithelial cells
- Move fluids over the epithelium
- Move fluids through the epithelium
- Produce secretions (protection and messengers)
protection
move fluids over the epithelium
permeability
move fluids through the epithelium
Protection and messengers
produce secretions
Move fluid
Cilia or ciliated epithelium
Increase absorption or secretion
Microvilli
Polarity surfaces can be _________ or _________
apical or basolateral
3 characteristics that maintain the integrity of the epithelia
- Intracellular connections
- Attachment to the basement membrane
- Epithelial maintenance and repair
Form bonds with other cells or extracellular material
Cell junctions
Kinds of cell junctions
- Tight junctions
- Gap junctions
- Desmosomes
Cell junctions are ________ _________
intracellular connections
Intracellular connections’ support and communication are done by:
- CAMS (cell adhesion molecules)
- Transmembrane proteins - Intercellular cement
- Proteoglycans - Hyaluronan (hyaluronic acid)
- Glycosaminoglycans
Proteoglycans are an example of intercellular connections that give support and communication via
intercellular cement
Glycosaminoglycans are an example of intercellular connections that offer support and communication via _________
Hyaluronan (hyaluronic acid)
- Between two plasma membranes
- Adhesion belt attaches to terminal web
- Prevents passage of water and solutes
- Isolates wastes in the lumen
Tight junctions
Attaches to terminal web (in tight junctions)
Adhesion belt
Tight junctions isolates wastes in the ________
Lumen
Prevents passage of water and solutes
Tight junctions
- CAMS, dense areas, and intercellular cement
- Spot desmosomes
- Hemidesmosomes
Desmosomes
Tie cells together
Allow bending and twisting
Spot desmosomes
Attach cells to the basement membrane
Hemidesmosomes
- Allow rapid communication
- Are held together by channel proteins (junctional proteins, connexons)
- Allow ions to pass
- Coordinate contractions in heart muscle
Gap junctions
Gap junctions are held together by channel proteins called _______ ________, _______
junctional proteins, connexons
Allow ions to pass
Gap junctions
Coordinate contractions in heart muscle
Gap junctions
Allow rapid communication
Gap junctions
Attachment to the Basement Membrane via a clear layer (lamina lucida) has what characteristics?
- Thin layer
- Secreted by epithelia
- Barrier to proteins
Attachment to the basement membrane via the dense layer (lamina densa)
-Thick fibers
-Produced by connective tissue
Strength and filtration
Dense layer is also known as
Lamina densa
Lamina lucida is also known as
Clear layer
Dense layer is also known as
Lamina densa
Clear layer is also known as
Lamina Lucida
Epithelium is singular or plural?
Singular
Epithelia is singular or plural?
Plural
Epithelia can be classified based on two things. What are these?
Shape and layers
Based on shape, epithelia can be what three things?
- Squamous epithelia
- Cuboidal epithelia
- Columnar epithelia
Thin and flat
Squamous epithelia
Square shaped
Cuboidal epithelia
Tall, slender rectangles
Columnar epithelia
Single layer of cells
Simple epithelium
Several layers of cells
Stratified epithelium
Simple epithelium and stratified epithilium are classified based on _______
Layers
Squamous epithelia, cuboidal epithelia, and columnar epithelia are a classified based on _______
shape
Epithelial maintenance and repair:
Epithelia are replaced by division of ________ _______ and happens ________ basement membrane
germinative cells (stem cells), near basement membrane
Epithelium in charge of absorption and diffusion
Simple squamous epithelium
Epithelium that lines body cavities
Mesothelium
Epithelium that lines heart and blood vessels
Endothelium