Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
29 Cards in this Set
- Front
- Back
|
Functions of the Epithelia
|
1 Protection
2 absorption 3 secretion 4 sensation 5 contractility |
|
|
Origin of Epithelia
|
From one of three:
1 Endoderm 2 Mesoderm 3 Ectoderm |
|
|
Epithelial characteristics
|
avascular
tightly packed and joined by special junctions basal attachment- basal lamina |
|
|
Terminal Bar
|
The horizontal density at top of the cell that contains the junctional complex
has tight junction, zonula adherens, desmosomes |
|
|
Zonula Occludens (tight junction)
|
Encircles entire cell near its apex
fusion of outer membranes of adjacent cells proteins: claudins and occludins prevents paracellular movement |
|
|
Intermediate junction, Adhesion Belt (Zonula adherens)
|
encircles cell underneath tight junction
cell cell adhesion done by a bundle of actin fibers which attach to transmembrane proteins which then attach to glycoproteins (E cadherins) |
|
|
Desmosome (Macula Adherens)
|
Proteins: desmoplakins and desmogleins, and desmocollin
cell to cell adhesion intermediate filaments attach to desmoplakins, gleins, and colins intermediate filaments don't actually span the junction |
|
|
Gap junctions
|
have poors where cytoplasm connected allowing coordiation and exchange ions
CONNEXINS creating a pore which is called a CONNEXON |
|
|
Hemidesmosomes
|
proteins: integrins and collagen binds cells to the basal membrane made by intermediate filaments
|
|
|
Basement Membrane
|
what the epithelium sit on
very easily seen in trachea PAS+ because of the complexed carbohydrates of proteoglycan heparan sulfate. |
|
|
Basement Membrane Two layers
|
Lamina lucida
lamina densa |
|
|
Lamina Reticularis
|
deep most layer of basement membrane
made by the connective tissue underneath lots of type 3 and 7 collagen |
|
|
Lamina Densa
|
made by epithelial cells
second deepest layer of basement membrane type 4 collagen laminin, proteoglycan heparan sulfate |
|
|
Brush Border
|
microvilli composed of actin anchored into the terminal web that forms zonula adherens
generally to increase surface area for absorption |
|
|
Stereocillia
|
don't move
no basal body found in the male reproductive tract |
|
|
Cillia
|
larger than microvilli and can see the basal bodies
|
|
|
Simple epithelium
|
one sheet
|
|
|
Types of epithelium
|
squamous- endothelium (lining of vessels), mesothelium (serous lining of cavities)
cuboidal- kidney tubules (with or without a brush border) columnar - small intestine (non-ciliated); oviduct (ciliated) |
|
|
goblet cells
|
cells in the columnar epithelium of the small intestine secrete mucus and don't stain very well
|
|
|
keritinized
|
must be squamous no nucleus toward the top
|
|
|
nonkeratinized
|
must see the nuclei up top have multiple layers of cels
|
|
|
Stratified
|
more than one layer
|
|
|
types of stratified epitheliume
|
squamous- either keratinizing or not
Cuboidal- in ducts of glands columnar- in terminal ducts of larger glands transitional- bladder and ureter, often these cells are binucleate |
|
|
Pseudostratified Columnar
|
with cilia and goblet cells: respiratory (nuclei at various levels as some cells do not reach surface).
|
|
|
Merocrine
|
Exocytosis (Pancreas) of secretory granules with cell remaining intact.
|
|
|
Apocrine
|
Some cytoplasm lost (Apocrine sweat glands)
|
|
|
Holocrine
|
Whole cell (Sebaceous glands) shed with secretory product.
|
|
|
Myoepithelia
|
Contain myosin and actin as well as intermediate filaments. Contract around secretory portion of gland
|
|
|
Four basic tissue types
|
Epithelia
Neurvous Muscle Connective |
