3. FUNCTIONS OF EPITHELIA
COVERING EPITHELIA
covering of surfaces and lining of cavities
protection of covered tissue
absorption - intestines, proximal tubules of kidney
GLANDULAR EPITHELIA
secretion - exocrine glands
NEUROEPITHELIAL CELLS
sensation - olfactory epithelium , taste buds
MYOEPITHELIAL CELLS
contractility - salivary glands, sweat glands
4.
5. COMPONENTS OF BASAL
LAMINA
COLLAGEN TYPE IV
LAMININ, FIBRONECTIN
(glycoproteins)
PROTEOGLYCANS (HEPARAN SULFATE)
ANCHORING FIBRILS COLLAGEN TYPE VII
21. TIGHT JUNCTION ZONULA OCCLUDENS
LOCATION - the most apical
SHAPE - band encircling the cell
MORPHOLOGY - network of linear fusion
sites between membrane associated proteins
FUNCTION - close off the intercellular space
(leakiness of the epithelium)
25. DESMOSOME MACULA ADHERENS
LOCATION - along the lateral membranes
DISK-SHAPED
MORPHOLOGY attachment plaques - desmoplaquin
intercellular space - desmoglein
cytokeratin filaments
FUNCTION - very firm adhesion of
neighbor-cells
27. ZONULA ADHERENS
LOCATION - just below tight junction
SHAPE - band encircling the cell
MORPHOLOGY dense plagues - α -actinin, vinculin,
myosin, tropomyosin
intercellular space - E-kadherin and
calcium ions
actin-containing microfilaments
FUNCTION - adhesion of neighbor-cells
28. HEMIDESMOSOME
LOCATION - contact zone
between epithelium and basal
lamina
DISK-SHAPED
MORPHOLOGY - half a
desmosome
FUNCTION - binds the epithelial
cell to basal lamina
30. GAP JUNCTION NEXUS
LOCATION - anywhere along the lateral
membranes of epithelial cells
MORPHOLOGY - hexamers of proteins
with a hydrophilic pore in the center
(connexon)
FUNCTION - interchange of small
molecules between adjacent cells (cyclic
AMP, ions)
36. CILIA
LONG PROJECTIONS - 10 µ m
MOTILE
STRUCTURE:
central pair of microtubuls
9 pairs at the periphery
INSERTED INTO BASAL BODIES
FUNCTION - permit a current of
material over epithelium
50. TYPES OF EXOCRINE GLANDS
APOCRINE
HOLOCRINE
secretory product is
discharged with
apical part of
cytoplasm
secretory product is
shed with whole cell
MEROCRINE
secretory granules leave
the cell by exocytosis
51.
52. NUTRITION OF EPITHELIA
NO BLOOD VESSELS IN EPITHELIA
NUTRIENTS AND PRECURSORS OF
PRODUCTS DIFFUSE FROM
CONNECTIVE TISSUE ACROSS THE
BASAL LAMINA TO EPITHELIAL CELLS