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58 Cards in this Set
- Front
- Back
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the basement membrane is attached to the ______ surface of epithelium
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basal
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epithelium is _________ in nature.
vascular / avascular |
avascular
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What are some functions of epithelial tissue in the human body?
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secretion
absorption protection transportation receptor function |
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The parenchyma of tonsils arises from which germ layer?
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endoderm
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Non epithelial tissues arise from which germ layer?
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Mesoderm
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Epithelial cells exhibit ________ and ________ polarity.
a) morphologic; chemical b) basal; morphologic c) morphologic; functional d) chemical; electrical |
c
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What are three types of surface modifications that arise from the Apical domain of epithelial cells?
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- microvilli
- stereocilia - cilia |
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Which contains an actin filament and are stabilized laterally by fimbrin?
a) microtubules b) intermediate filaments c) cilia d) microvilli |
d
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The contractibility of microvilli are dependent upon:
a) actin and myosin b) myosin II and tropomyosin c) villin and fimbrin d) intermediate filaments e) non of the above |
b
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Which is false regarding stereocilia?
a) Only found in the male reproductive tract and inner ear b) very long, motile microvilli c) supported by fimbrin and villin d) anchored to the membrane by ezrin |
c
supported by actin and fimbrin |
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_______ anchors microvilli to the membrane whereas ________ anchors stereocilia to the membrane.
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spectrin; ezrin
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Which type of cilia continuously renew?
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stereocilia
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What is the treadmilling effect?
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refers to the renewal process of stereocilia, treadmilling effect of the actin core is highly regulated process dependent upon the length of the stereocilium (adds to the tips and remove from the base)
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Hair-like extensions common to most cells are known as
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cilia
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The internal structure of cilia most represent
a) actin filament b) microtubule based c) intermediate filament based d) myosin based e) non of the above |
b
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What is an axoneme?
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microtubule based internal structure of cilia - doublets of microtubules arranged in a circular fashion +/- one in the centre
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Which is false regarding cilia?
a) motile cilia have a 9+2 internal microtubule structure b) immotile (monocilia) have a 9+2 internal microtubule structure c) motile cilia are found in the oviduct, trachea and olfactory epithelium d) monocilia are found on almost all eukaryotic cells |
b
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Where are nodal cilia located?
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embryo during gastrulation near the primitive node
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nodal cilia function?
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rotational movement
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What are MAMPS?
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Microtubule‐associated motor proteins
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What kind of axonemal structure do nodal cilia posses?
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same axonemal structure as primary (monocilia) cilia but with MAMPs
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Which statement is false?
a) Cilia are visible by light, not microvilli b) actin within cilia, microtubules within microvilli c) Cilia active or passive movement, microvilli only passive d) Cilia longer than microvill |
b - opposite
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What are CAMs?
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cell adhesion molecules - provide junctions between neighboring lateral domains
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What are the 2 functions of junctional complexes?
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1 - join epithelial cells to one another
2 - barrier to passive diffusion of substances |
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Which is false?
a) zonula occludens is a tight occluding junctional complex b) gap junctions are occluding junctional complexes c) zonula adherens is a spot anchoring junctional complex d) fascia adherens is a sheet anchoring junctional complex |
b - gap junctions are communicating junctions
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Which type of junctional complex forms a tight junction and the primary intercellular diffusion barrier?
a) zonula adherens b) macula occludens c) zonula occludens d) gap junction e) non of the above |
c
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What is the fucntion of occludin?
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maintains
barrier between cells and between AD and LD (in zonula occludens) |
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What is the function of claudins?
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form backbone
of each strand and extracellular aqueous channel |
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What are JAMs?
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Junctional Adhesion Molecules - associated
with claudins – formation of ZO in endothelial cell |
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Where are focal adhesions and hemidesmosomes located?
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at the connective tissue matrix border of epithelial cells
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Macula adherens is a _______ junctional complex. It is _______ dependent and the intermediate line is formed by __________ and ____________ .
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spot; Ca2+; desmocollin-desmoglein adhesion molecules
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How are CAMs classified?
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categorized by molecular structure:
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Which statement is false regarding Cellular Adhesion Molecules?
a) cadherins regulate growth and differentiation b) selectins are present in WBCs and endothelial cells c) integrins posses two transmembrane glycoprotein subunits d) Integrins regulate neutrophil migration, and the homing procedure of lymphocytes |
d
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What type of junctional complex would you find much of in the intestine (i.e. to mediate peristalsis)?
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gap junctions
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Which structure is comprised of 6 internal connexin subunits, forming one connexon?
a) microvilli b) intermediate filaments c) gap junctions d) desmosomes e) none of the above |
c
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Two connexons form what?
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a channel between two adjacent cells for communication
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What is the function of plicae? Where are plicae usually found?
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f(x) increase SA
found on cells usually engaged in fluid |
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Sodium ions diffuse out of the cell, followed by anions and water. Why is there no leakage?
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zonula occludentes prevent leakage
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What is the basement membrane?
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Acellular zone between the basal domain and underlying
connectitive titissue (CT) (CT) sttroma |
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What is the purpose of basal cell membrane infoldings?
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• Increase surface surface area area
• Facilitate interaction between adjacent cells and ECM proteins |
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Basal lamina and reticular lamina are the two layers of what?
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basement membrane
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Which statement is false regarding basal lamina?
a) it is an electron dense region b) Network of laminins, collagen type IV molecules, proteoglycans and glycoproteins c) Molecular composition and function differs from tissue to tissue d) Molecules within BL interact with receptors on cells e) none of the above f) all of the above |
e
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What are some functions of the basal lamina?
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Structural attachmen
Compartmentalization Tissue scaffoldin Scaffolding Regukation & Signalling |
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Focal adhesions anchor the __________ to the __________.
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actin filaments; basement membrane
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hemidesmosomes anchor the __________ to the __________.
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intermediate filaments; basement membrane
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Which statement is true?
a) hemidesmosomes are weak and unstable, and therefore prone to abrasion b) hemidesmosomes anchor actin filaments to the basement membrane c) hemidesmosomes are important in the apical domain d) they are a variant of desmosomes |
d
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Why might mitochondria be concentrated at the basal site?
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in cells which are heavily involved in activ transport, therefore need lots of ATP and correspondingly lots of mitochondria. Aligned mitochondria give a striated appearance in lm
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Exocrine glands secrete product onto a surface directly OR
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through a duct
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Endocrine glands lack ducts; they secrete their products into
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blood stream VIA CT and produce hormones
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What are autocrine cells?
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Secretions act on the cell that produces them via receptors on the cell surface
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What are paracrine cells?>
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Secretions do not reach bloodstream – act on neighbouring cells via diffusion
through the EC |
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What three categories are exocrine glands classified into?
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Merocrine
Apocrine Holocrine |
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Acinar cells of the pancreas are an example of a ________ gland, where products are secreted by __________.
a) merocrine; product release surrounded by thin layer of cytoplasm b) apocrine; endocytosis c) exocrine; directly to blood stream d) merocrine; exocytosis |
d
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What type of cells secrete mucous?
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golbet cells
salivary glands |
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Where would you likely have serous secretion?>
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pancreatic cells
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secreting cells of endocrine glands tend to be ______ in shape.
a) oval b) cuboid c) round d) non distinctive |
c
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Islets of Langerhans - example of what type of gland?
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endocrine
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Give two examples showing epithelial cell renewal
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small intestine - renewal every 4-6 days
skin (stratified squamous) - every 28 days |
