Epithelum Flashcards
Epithelia
Layers of cells that cover internal or external surfaces
Epitheal tissue
Includes the surface of your skin
Glands
Are structures that produce fluid secretion; they are ethier attached to or deprived from epithelia
Cellularity
Composed mostly of cells bound closely together by interconnections known as cell junctions
Polarity
Uneven distribution of membrane functions and organelles between the exposed
Attachement
The base of an epithelium is bound to a thin basal lamina.
Avascularity
Do not contain blood vessels
Regeneration
Epithelial cells are damaged or lost are continuously replaced
Functions of epitheal tissue
Provide physical protection
Control permeability
Provide sensation
Produce specialized secretions
Glandular epithelium
Most or all of the epi cells produce secretions which are ethier discarded onto the surface of the epi to provide physical protection or released into the surrounding interstitial fluid and blood to act as chemical messengers
Apical surface
The cell is exposed to an internal or external environment
Basolateral
Includes both the base, where the cell attaches to underlying epi cells and on the sides
Ciliated epi
Contains cilia
Cell adhesion molecules
Large areas of opposing cell membranes are interconnected by transmembrane proteins
Intercellular cement
Thin layer of proteglycans that contain polysaccharide derivatives
Hyaluronan
Polysaccharide derivatives known as Glycosaminoglycans
Cell junctions
Specialized areas of cell membrane that attach a cell to another cell or to extra cellular materials.
Tight junctions
Lipid portions of the two cell membranes are tightly bound together by interlocking membrane proteins
Lumen
When the epi lines a tube the apical surface is exposed to the space inside the tube, a passageway
Gap junction
Two cells are held together by interlocking membrane proteins called connexons
Desmosome
CAMs and proteglycans link the opposing cell membranes
Lamina lucida
Layer closet to the epi
Lamina densa
Deeper layer of the basal lamina
Endocrine glands
Release their secretion into the interstitial fluid
Exocrine glands q
Release their secretions into passageways called ducts that open onto the epithelial surface
Endocrine ex
Thyroid gland and pituitary gland
Melocrine secretion
The product is released from secretory vesicles by exocytosis
Apocrine secretion
Involves the loss of cytoplasm
Holocrine
Destroys the gland cell
Serous glands
Decrease a watery solution that contains enzymes. The Paramus salivary glands are serous glands
Mucous glands
Secrete mucins that hydrate to form mucus
Mixed exocrine glands
Contains more than one type of gland cell and may produce two differ t exocrine secretions, one serous and one mucous .
