510-4 Flashcards
What are four main features of Epithelium?
1)There is a FREE surface (environment or internal body cavity) 2)BASAL surface(attached to a basement membrane) 3)AVASCULAR-depend on diffusion for nutrients 4)INNERVATED-paper cuts hurt but don’t bleed
What are the two components of a basement membrane?
Basal Lamina & Reticular Lamina
What is the basal lamina composed of? Where is it made?
The basal lamina is a complex mix of PROTEINs. Made by epithelial cells and underlying FIBROBLASTS
What is the main glycoprotein of the lamina lucida? What fiber does it bind to the best?
The main glycoprotein is LAMININ (looks like a cross). It binds the the TYPE IV collagen(Lamina Densa Below!)
What are the three main types of fibrils that connect the basal lamina and the reticular lamina?
Type I, Type III, and Type VII collagen fibrils.
Which collagen fibrils attach to the basal lamina and then loop around other collagen fibril types?
Type VII
What classifications of epithelium do goblet cells fall under? What substance to they secrete?
Simple Columnar & Pseudostratified Epitheliums. They secrete mucus.
What are the three types of cells in pseudostatified epithelium?
Shorter, basal cells and taller, goblet & ciliated cells.
What are the three main components of a mucous membrane?
1)Epithelium (mucous producing[think simple columnar or pseudostrat]) 2)Lamina Propria(Vascular connective tissue) 3)Muscularis mucosae(thin layer of SMOOTH muscle)
What are keritinized cells generally coated with to reduce water loss?
Lipids! Hydrophobic, eh?!
What type classification of epithelium makes up the oral mucosa? What is the most unique feature of this type of epithelium?
Nonkeritinized Stratified Squamous Epithelium. Its resistant to Abrasion!
Where can KERATINIZED Strat. Sq. Epi be mainly found? What are the two main functions of the layer?
Skin! Oral Epithelia!:Eg. Gingiva, Hard Palate, and Tongue Papillae.
What are the typical basal cell of stratified cuboidal or columnar epithelia?
Typically CUBOIDAL basal cells with either the cuboidal or columnar on top of them.
Where is transitional epithelium found and what (subtype) of epithelium is it? What unique feature forms on the free side?
Ureters and bladder (UROTHELIUM). Pseudostratified. Plaque domes made of protein to protect the cells from urine.
Name the five types of intercellular junctions (W/ LATIN names too)
Tight Junction (zonula occludens), Adhesive Junction (zonula adherens), Desmosomes (macula adherens), Gap Junction, Hemidesmosome
What is the difference between a zonula and a macula?
zonula=around cell; macula=patch
Fxn of Tight Junction. Rate its strength.
Tight junctions seal neighboring cells in an epithelial sheet to prevent leakage. It is the weakest of the junctions.
Fxn of adhesive junctions. Strength?
Joins actin bundles from cell to cell. Mid level strength.
Fxn of desmosomes. Strength?
Join intermediate filaments of two cells. STRONGEST.
Fxn of Gap Junction
Allow passage of small, water soluble molecules from one cell to another. COMMUNICATION. Not for strength.
Fxn of Hemidesmosome
Anchors the cell to the BASAL Lamina
What type of pattern do tight junctions make in between cells?
A quilt like pattern. The more strands the more impermeable the junction is to water.
What are the 3 main proteins involved in tight junctions? FASCINATING!!
Claudin, Occludin (hence zonula occludens), & JAM(junctional adhesion molecules)
What are the two main proteins involved in adhesive junctions? How do they interact? What ion must be present?
1)actin filaments inside the cell anchor 2)cadherin proteins that reach out of the cell and hook to other cell’s cadherins. Ca2+ is essential for this cadherin linkage.
What are the main proteomic components of desmosomes?
INSIDE CELLIntermediate fillaments(Keratin)—structural protein plaque(plaktoglobin)—OUTSIDE CELL more connective proteins (desmoglein) COOL NOTE: they distribute shear forces from one cytoskeleton to another through this type of linkage.
Describe the structure of the hemidesmosomes.
INSIDE CELL intermediate filament—OUTSIDE CELL stuctural proteins (laminin) + type VII collagen fibers
Where are gap junctions most abundant?
embryo, cardiac, and smooth muscle
What is the difference between connexin and connexon.
Connexin is the transmembrane protein monomer. Connexon is the channel that is formed when two connexins link up.
What type of tissue are most predominant in GLANDS?
Predominantly epithelial tissue
What is the difference between exocrine and endocrine glands?
Exocrine glands= DUCTS Endocrine glands=NO DUCTS
What are three examples of mixed (endocrine & exocrine) organs.
PANCREAS (digestive enzymes into ducts & hormones into blood), LIVER(bile into ducts, insulin into blood), GONADS (gametes into ducts, hormones into blood)
What are the 2 types of glands? What does it mean about branched vs unbranched?
Simple=unbranched Compound=branched
What are the three shapes of glands?
TUBULAR-the ductile cells are secretory ACINAR-secretatory cells form a dilated sac (acinus) TUBULOACINAR-secretatory cells are in both ductal and acinar regions of the gland. (BOTH TUBULAR + ACINAR)
BIG CONCEPT: the four types of glandular secretions
SEROUS Glands (sweat, milk, tears, & digestive juices) MUCOUS Glands (glycoprotein + mucin + water = mucus) MIXED glands (serous and mucus) CYTOGENIC glands (whole cells into ducts (testes and ovaries)
What are the three basic cellular mechanisms of glandular secretion?
Merocrine, apocrine, and holocrine
Describe merocrine secretion
Merocrine=Merge-o-crin: A granule’s membrane fuses with a apical membrane and releases its content (exocytosis) no loss of cytoplasm MOST COMMON
Describe apocrine secretion
Dependent on sex hormones: granule goes to apical portion of cell then membrane PINCHES off.
Describe holocrine secretion
Breakdown and discharge of ENTIRE secretory cells e.g. sebaceous glands
