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Epithelium
LECOM Yr 1
68
Anatomy
Graduate
08/05/2011

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Cards

Term
what are the 5 functions of epithelium?
Definition
protection, absorption, secretion, sensation, contraction
Term
protective epithelium are typically what type of epithelia?
Definition
stratified or multilayered; ex: epidermis of the skin, lining of esophagus
Term
absorptive epithelia are typically what type of epithelia?
Definition
simple or single layered and have surface specializations to increase the absorptive surface area; ex: intestinal epithelium
Term
True or False: all glands form from epithelia?
Definition
True
Term
what do acini do to glands?
Definition
squeeze glands to allow release of product
Term
what are myoepithelial cells?
Definition
specialized epithelial cells found in the acini of glands, these cells help to squeeze the secretory product from the gland
Term
basal lamina is formed by what type of cells?
Definition
epithelial cells
Term
what are some basic characteristics of epithelium?
Definition
avascular, cells are tightly packed, epithelial tissues form coverings or linings of organs and form glands, all epithelial tissues have a basal lamina, all epithelial tissues are characterized by intercellular junctions or specializations
Term
What forms the reticular lamina?
Definition
connective tissue
Term
what are the 3 major components of the basal lamina?
Definition
COLLAGEN TYPE IV, laminin, fibronectin
Term
what is the basal lamina?
Definition
structural layer that underlies epithelia; can serve as a filter, serves to organize tissues, separates epithelia from the underlying connective tissue, attachment to basal lamina gives epithelial cells polarity
Term
True or False: Basal lamina serve a role in tissue migration during development.
Definition
True
Term
The reticular lamina is what collagen type?
Definition
TYPE I
Term
what is the basement membrane?
Definition
may be 2 basal laminae together as in the renal glomerulus; more often, it is a basal lamina with an underlying reticular lamina
Term
anchoring fibrils in the basement membrane are what collagen type?
Definition
TYPE VII COLLAGEN
Term
what are some specializations of the apical domain?
Definition
microvilli, cilia, stereocilia
Term
what are characteristic of the lateral domain?
Definition
cell-cell junctions
Term
how is polarity induced in the epithelial cells?
Definition
by interactions with basal lamina and underlying connective tissue; concentration gradients
Term
True or False: all epithelial tissues are characterized by intercellular junctions or specializations.
Definition
True
Term
what is a desmosome (macula adherens)?
Definition
patch like connection between adjacent cells; serves to hold the cells tightly together; have intermediate filaments associated with them; particularly abundant in epithelia that are exposed to physical stress
Term
what does it mean when a tissue has many desmosomes?
Definition
that tissue undergoes a lot of force
Term
What are the intermediate filaments made up of in desmosomes?
Definition
cytokeratin
Term
what type of cells make desmosomes?
Definition
glial cells
Term
what is the function of a hemidesmosome?
Definition
attaches basal cells to the basement membrane; prominent in epithelia exposed to physical forces as experienced by epidermis
Term
what is the name of the disease in which antibodies attach to certain proteins associated with hemidesmosomes causing them to detach from the underlying basement membrane?
Definition
Bullous pemphigoid; causes blisters
Term
what are gap junctions (nexus junctions)?
Definition
allows cells to communicate electrically, ions and small particles can pass through (smaller than 1500 daltons), these communications become important in tissues that have to function all together (ex: heart), composed of connexons
Term
what does the terminal bar join?
Definition
the apical ends of cells
Term
True or False: the terminal bar goes all the way around the apex of the cell
Definition
True
Term
what are the 3 junctions that compose the terminal bar?
Definition
tight junctions (zonula occludens), zonula adherens and macula adherens
Term
True or False: There is some actin in the terminal bar
Definition
True
Term
What is the function of the tight junction?
Definition
allows for regulation by the cell, prevents paracellular route, completely surrounds the cell like a belt or a band
Term
what is the function of the zonula adherens?
Definition
functions to hold adjacent cells together, had actin microfilaments associated with it, has morphological similarities to the desmosome in action
Term
what is the function of the junctional complex?
Definition
prevents materials from passing between cells via the intercellular route
Term
the enterotoxin made by C. perfringens attacks what part of the epithelium to cause intense diarrhea and abdominal pain?
Definition
the zonula occludens (tight junctions)
Term
what are microvilli specialized for?
Definition
absorption
Term
what is the core of microvilli consist of?
Definition
actin
Term
where can microvilli be found in the body?
Definition
the kidney and small intestine
Term
what are cilia made up of?
Definition
a cytoskeleton made up of nine doublets of microtubules and a central pair of microtubules
Term
what is the function of cilia?
Definition
movement; tracheal cilia move mucous toward the pharynx
Term
which is longer: microvilli or cilia?
Definition
cilia
Term
True or False: All cilia have a basal body associated with them
Definition
True
Term
what is dynein?
Definition
an ATPase which functions as a motor for ciliary movement
Term
what is the clinical term a case in which an individual has an absence of dynein and suffers from frequent respiratory infections?
Definition
Kartegener's Syndrome
Term
what are stereocilia?
Definition
sensory type structures with very long cellular processes; not involved in movement; their deflection causes changes in membrane potential; internal structure similar to microvillus
Term
where are stereocilia found?
Definition
found ONLY in the epididymis and the inner ear
Term
what does it mean for an epithelium to be keratinized?
Definition
outter layer is dead
Term
what are goblet cells?
Definition
single celled glands (secretion)
Term
True or False: In pseudostratified ciliated, all the cells rest on the basal lamina.
Definition
True
Term
what is a transitional epithelium?
Definition
an epithelium that adapts to distension of the urinary tract; characterized by dome-shaped cells
Term
what are the 2 major types of glands?
Definition
exocrine and endocrine
Term
True or False: all glands develop as ingrowths of epithelial cells into the underlying connective tissue
Definition
True
Term
What are the 3 mode of secretion for exocrine glands?
Definition
holocrine, apocrine, merocrine
Term
what happens during holocrine secretion?
Definition
the entire cell fills with secretory product and then the cell is shed- sebasceous and tarsal glands; they undergo apoptotic death and release all their product
Term
what happens during apocrine secretion?
Definition
the apical end of the cell is filled with secretory product and that part of the cell is released; ex: mammary glands; apocrine is very large secretory granules are released. Note: the entire apex does not break off
Term
what happens during merocrine (eccrine) secretion?
Definition
secretory cells are formed, accumulated near the apical end of the cell and are released by exocytosis; ex: pancreatic acinar cells
Term
True or False: Several goblet cells are present at the Crypt of Lieberkuhn (intestinal gland in the colon)
Definition
True
Term
what is dysplasia?
Definition
changes in size, shape or organization of cells (can be precancerous)
Term
what is hyperplasia?
Definition
increased number of cells; for example: increased number of erythrocytes at a high altitude
Term
what is hypertrophy?
Definition
enlarged cells
Term
what is hypoplasia?
Definition
decreased number of cells
Term
what is hypotrophy (atrophy)?
Definition
cells smaller than normal; if the nerve to a muscle is severed the muscle cells atrophy
Term
what is pleomorphism?
Definition
many different sizes and shapes of cells
Term
what is anaplasia?
Definition
new cells change to a different cell type than the existing cells
Term
what is metaplasia?
Definition
existing cells change to a different cell type
Term
what is a benign papilloma?
Definition
benign tumor arising from a surface epithelium
Term
what is a benign adenoma?
Definition
a benign tumor arising from a glandular epithelium
Term
what are the factors that affect malignancy of a tumor?
Definition
anaplasia, mitotic activity, invasion, metastases
Term
what is an adenocarcinoma?
Definition
a carcinoma arising from glandular tissue
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