Flashcards in Hovorka-Epithelium and Glands Deck (44):
what are the major functions of epithelial tissues?
secretion, absorption, transport, protection, receive external stimuli (retina, tongue, inner ear, smell)
what are the typical locations of epithelial tissues?
covering surfaces, lining cavities, forming the secretory portion of glands and their ducts
characteristics of epithelial tissues?
strong cell adhesions, apical surface faces a lumen, avascular, attached to basement membrane
what type of epithelium has a single layer?
what type of epithelium has 2 or more layers?
what shape are flat cells?
what shape are cube cells?
what type of cell is taller than they are in width?
what type of cell may appear cuboidal when relaxed but when stretched appears squamous?
transitional cells (important for the urine collection system)
what part of the cell is modified in brush border, sterocilia and cilia?
what does the endothelium line?
simple squamous epithelium that lines blood vessels
what does mesothelium line?
simple squamous epithelium that lines body cavities
how are microvilli usually arranged and what is there purpose?
packed microvilli form a brush border and they are important for absorption
what is another name for extra-long microvilli?
what is the function of cilia?
in what domain do cell to cell junctions form?
name the three lateral domain junctions.
occluding, anchoring and communicating
what is the function of occluding junctions?
prevent membrane proteins from moving between the apical and lateral domains (barriers)
what are the two types of anchoring junctions?
zonula adherens and desmosomes
what are zonula adherens?
belt-like junctions that interact with the actin cytoskeleton
what are desmosomes?
(macula adherens) "spot weld" type junctions that interact with the intermediate filament cytoskeleton of the cell.
what are communicating junctions?
(gap junctions) create a conduit thru which ions and small molecules can freely diffuse between the cytoplasm of adjacent cells.
name the two major types of basal domain adhesions.
what do focal adhesions attach too?
these junctions attach the actin cytoskeleton to the extracellular matrix
what do hemidesmosomes attach too?
attach the intermediate filament cytoskeleton to the ECM.
what is the basal lamina (closest to the epithelium) composed of?
type IV collagen, laminin, proteoglycans and glycoproteins
what type of stain is best to visualize the basal lamina?
best visualized with PAS stain due to the carbohydrates of the proteoglycans and glycoproteins
what are the layers of the basal lamina?
lamina densa (filament layer) and lamina rara (clear layer)
what the third possible layer of the basement membrane that some cells contain?
reticular layer (separate from basal lamina)
how are glands formed?
invagination of epithelial tissue
how do exocrine glands secrete their products?
secrete their products onto a surface, either directly or thru ducts
what are three types of glands?
merocrine, apocrine and holocrine
how are the contents of merocrine glands secreted?
product is released when vesicle fuses with the plasma membrane at the apical surface of the cell (exocytosis)
how are the contents of holocrine glands secreted?
the product accumulates in the cell and when the cell undergoes apoptosis the content is released in lumen
how are the contents of apocrine glands secreted?
they bud off from the apical plasma membrane. since budding occurs the plasma membrane must be regenerated in the cell
how do products of endocrine glands travel?
the secreted hormones travel via the bloodstream to target tissue
how are exocrine glands further divided?
serous, mucus, seromucus
what type of cell has a well developed rough ER and secretion that is thin, watery and protein rich?
what is the texture of mucus and what is unique about its small protein core.
viscous, and it contains negatively-charged carbohydrates
what is unique about seromucus glands?
mucus secreting cells along the tubular portion that is capped by serous secreting cells
what type of glands make up ducts?
what term describes branching ducts?
is it true that multiple glands leading to one duct is considered branched?