PPT 4 Epithelia Flashcards
The side of the epithelia that is attached to the basement membrane is called _______.
Basal Surface
The end of the epithelia that may be is exposed to either the environment or an internal body cavity is called ________.
Free Surface
Are epithelia vascular or avascular?
Avascular
Are epithelia innervated or not innervated?
Innervated
Two parts of the basement membrane are ________ and _______.
Basal Lamina
Reticular Lamina
Basal epithelial cells contribute _____, ______, and ________ to the basal lamina.
laminin, entactin and type IV collagen
Fibroblasts in the connective tissue under epithelia contribule molecules including ______ and ______ to the basal lamina.
Fibronectin and proteoglycans
The ________ is a layer of the basement membrane seen in some epithelia that attaches to the underlying connective tissue.
Reticular lamina
The basal lamina is composed of 2 parts. A thin, light staining _____ and a darker staining _____.
Lamina Lucida
Lamina Densa
The lamina lucida contains a protein called _______ that is secreted by the epithelial cells and binds to type IV collagen. It also bridges the lamina lucida and lamina densa to the plasma membrane.
Laminin
The lamina densa is composed of _____.
Type IV Collagen
Basal lamina and reticular lamina are joined together by type I and type II collagen fibrils that weave through loops of ______.
type VII collagen anchoring fibrils.
Epithelia are named for:
1.
2.
3.
Number of layers of cells (Simple, stratified)
Shape of cells at the free surface (Squamous, Cuboidal, Columnar, TransitionalQ)
Surface modifications (Cilia, microvilli, keratinized)
Simple Squamous Epithelium allow _____.
Found in _____, _____ and _____.
Rapid diffusion
Alveoli, glomeruli, blood vessels
Simple cuboidal epithelium (often with microvilli) functions include _____, _____ and _____.
Found in _____, _____, _____, _____, _____, _____, and _____.
absorption, secretion, conduction
liver, thyroid, bronchioles, kidney tubules, mammary glands, salivary glands and other glands.
Simple Columnar Epithelium may have microvilli or cilia
Functions: _____ and _____.
Lines the _____ and _____
absorption and secretion
Intestines and ducts of glands
Psuedostratified Epithelium (ciliated) Function: \_\_\_\_\_ and \_\_\_\_\_\_\_
Found in the _____ including the _____ and _____.
secretes and propels respiratory mucus
upper respiratory tract, trachea and nasal cavities
The 3 layers of mucous membranes are:
1.
2.
3.
Epithelium
Lamina Propria
Muscularis Mucosae
Nonkeratinized Stratified Squamous Epithelium:
forms an abrasion-resistant, moist, slippery layer
Locations include ______, _____ and _____.
Oral Mucosa, esophagus, vagina
Keratinized Stratified Squamous Epithelium
Found in _____ and _____.
epidermis and some oral epithelia (gingiva, hard palate and tongue papillae)
Stratified cuboidal and columnar epithelia can be found in the larger ducts of some glands including the _____, _____ and _____.
pancreas, salivary glands and sweat glands.
Transitional Epithelium
Characterized by _____ surface.
Found in the _____ and _____.
rounded (domed)
ureters and urinary bladder
Name the 5 Intercellular Junctions.
- Tight Junction (Zonula Occludens)
- Adhesive Junction (Zonula Adherens)
- Desmosome (Macula Adherens)
- Gap Junction
- Hemidesmosome
Zonula describes
junctions that completely encircle a cell
macula describes
junctions that are in specific spots
These junctions seal together neighboring cells in an epithelial sheet to prevent leakage between cells.
Tight Junctions (Zonula Occludens)
These junctions join actin bundles in one cell to actin bundles in an adjoining cell.
Adhesive Junctions (Zonula Adherens)
These junctions join the intermediate filaments in one cell to those in an adjoining cell.
Desmosomes (Macula Adherens)
These junctions allow passage of small, water-soluble molecules from one cell into another.
Gap Junction
These junctions anchor intermediate filaments in a cell to the basal lamina.
Hemidesmosome
Rank from strongest to weakest junction.
Adhesive junction (Zonula Adherens)
Tight Junction (Zonula Occludens)
Desmosome (Macula Adherens)
Strongest: Desmosome
Adhesive Junction
Weakest: Tight Junction
Tight junctions are composed of transmembrane adhesive proteins including _____, _____ and _____.
Claudin, occludin and other cell-specific junctional adhesion molecules called JAMs
Adhesive junctions are principally composed of the ______ cadheerin family of transmembrane proteins.
calcium ion-dependent
These junctions are composed of attachment plaques of structural proteins linked to intermediate filaments of the cytoskeleton, like keratin, and to integral membrane proteins like cadherin.
Desmosomes
In desmosomes, the cadherins are _____ and ______.
desmoglein and desmocollin
Abundant intracellular proteins, called _____, _____ and ______, form dense plaque that anchors intermediate filaments. These filaments link to other cytoskeletal proteins and thus distribute shearing forces from the cytoskeleton of one cell to another.
plakoglobin, desmoplakin and plakophilin.
These junctions link intermediate filaments of a cell at the basal membrane of cells to collagen fibers in the basement membrane, and then through other structural proteins, including laminin, to the underlying connective tissue.
Hemidesmosomes
Gap junctions are made up of 6 transmembrane protein monomers, called ______, which form a water-filled channel called a ______.
connexin, connexon.
Gap junctions are clusters of _______.
Connexons
_______ glands mainntain a connection to a surface through a duct.
Exocrine
_____ glands do not have ducts but secrete their products (hormones) directly into the blood or intercellular fluids.
Endocrine
_____ glands have an unbranched duct.
Simple
_____ glands have branched ducts.
Compound
If the ductal cells are secretory the shape of the gland is ______.
tubular
If the secretory cells form a dilated sac the shape is _____. the sac is called an _____.
acinar, acinus
If the secretory cells are in both the ductal and acinar regions of the gland the gland shape is classified as ______.
tubuloacinar.
______ glands produce thin, watery secretions such as sweat, milk, tears and digestive juices.
Serous
_____ glands produce a glycoprotein, mucin, that absorbs water to form a sticky secretion.
Mucous.
______ glands contain both serous and mucous cells.
Mixed
______ glands release whole cells into ducts.
Cytogenic
3 basic cellular mechanisms of glandular secretion are ______, ______ and ______.
merocrine, apocrine and holocrine
The most common type of secretion through exocytosis is called ______. The secretory granules leave the cell with no loss of cytoplasm.
merocrine
Less common and dependent on sex hormones, _______ secretion is when a portion of the cytoplasm of the cell simply pinches off enclosing the granules.
apocrine
The breakdown and discharge of entire secretory cells is called ______ secretion.
holocrine
