L2 - Epithelia Flashcards
Cytosol
Liquid of cytoplasm
Metastasis
Spread
Goblet cell
Modified columnar cell that fills up with mucus (creating a bulge) and aids lubrication of material that passes across the apical surface
Keratin
Tough, fibrous, intracellular protein that helps protect skin and underlying tissues from heat, microbes, and chemicals
Epithelia key functions
- selective barriers (limit/aid transfer)
- secretory (onto surfaces/into ducts)
- protective (especially from abrasion)
Microfilaments function
- alters cell shape
- strength
- muscle contraction
- bundles beneath cell membrane/cytoplasm
- links cytoplasm to membrane
- tie cells together
Intermediate filament function
- strength
- transport materials through cytoplasm
Tight junction locations in body
Stomach, intestine, bladder
Desmosome junction location
Skin epithelium, cardiac cells of heart (to prevent pulling apart) - binds muscle cells
Gap junction locations
Heart, nervous system, gastrointestinal tract, uterus
Tight junction composition
Sealing strands of transmembrane proteins join cytoskeleton of adjacent cells
Desmosome keratin
Keratin spans from one desmosome to another on other side of cell - structural integrity
Gap junction connection
Direct connection between cells
Tight function features
- electrochemically tight (no ions)
- keeps cell polarity (migration of proteins between apical and basal surfaces prevented)
- sealed passageways between adjacent cells (no leaking contents)
Adherens junction features
- prevents cell separation from tension forces in contractions
Desmosome junction features
- resist shearing forces
Gap junction features
- communication (chemical/electrical signals, nerve/muscle impulses)
- molecule transportation (ions, NAD, ATP, small parts of DNA, RNA)
- some waste/nutrient transfer (in eye lens/cornea)
Hemidesmosome junction features
- stops cells from sliding around
Junctional complex
Combo of tight, adherens, desmosome
Basal lamina composition
Collagen, laminin, other proteoglycans, glycoproteins
Reticular lamina composition
Fibronectin, collagen
Basement membrane functions
1) support epithelium
2) provide surface for epithelial cells to migrate during growth and wound healing
3) act as physical barrier (restricts larger molecules to pass/invasion by melanoma)
4) participates in filtration of substances in kidney
Covering/lining epithelia composition
Often have secretory cells scattered in them
Outer covering examples
Skin, some internal organs
Inner lining examples
Blood vessels, ducts, body cavities, interior of respiratory, digestive, urinary, reproductive systems
Simple. Function
Diffusion/osmosis, secretion, absorption, filtration
Stratified. Function
Protective, (limited secretion and absorption)
Pseudo-stratified function
Secretion, (absorption, protection)
Squamous function
Diffusion
Cuboidal function
Secretion, absorption
Columnar function
Secretion, absorption
Transitional shape change
Stratified: cuboidal to squamous
Simple squamous features
Most delicate
Simple squamous functions
Filtration, diffusion, secretion