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20 Cards in this Set
- Front
- Back
Examples of tissues with permanent cells
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-auditory hair cells (in the organ of corti in the inner ear)
-rods & cones in the retina |
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What is characteristic of permanent cells?
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-made once during fetal development; if destroyed, they are gone forever
-All though they don't proliferate, they are still very much alive - they are ongoing RNA and protein synthesis |
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if liver cells are completely destroyed, what cells will regenerate the liver
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peri-ductular cells (oval cells)
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what are the characteristics of a stem cell?
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-cell that is not terminal differentiated
-cells that can divide without limit -daughter cells have the choice of remaining a stem cell or committing to a pathway of differentiation |
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transient amplifying cells
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-stem cells give rise to transient amplifying cells which go through a limited series of more rapid determinaations prior to differentiation
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In epithelial cells, where is proliferation occuring?
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-in the basal cell layer (attached to the basal lamina)
-60% of basal cells are proliferation -5-10% of the cells are stem cells |
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What are the layers in the epithelium?
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-prickle layer
-granular layer -keratinized squames |
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Prickle layer
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found just about the basal cell layer and right below the granular cell layer
-keratin gene expression changes as the cell moves upward -prickly appearance results from insertion of keratin bundles into desmosomes |
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Granular layer
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-cells begin to loose their nuclei
-granular appearance from densely staining aggregates of keratohyalin ( which is involved in intracellular compaction and keratin crosslinking) |
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keratohyalin
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- found in the GRANULAR LAYER
-(which is involved in intracellular compaction and keratin crosslinking) |
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what causes the layers in the epidermis?
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- differenes in expression of keratin genes as you move through the layers
-the order is: basal cell layer, prickle cell layer, granular cell layer, keratinized squames |
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stem cells in the small intestine give rise to:
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-absorbtive lineage
-secreating lineage -goblet cells -enteroendocrine -paneth cells |
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paneth cells
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cells at the bottom of the crypt, don't divide, just secrete factors used in bacterial defense.
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What is the difference between the epidermis and the intestinal epithelium in terms of potency and structure?
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epidermis -unipotent & multiple layers
intestinal epithelium - multipotent and single layered |
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Difference between colon and small intestine epithelium?
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- colon has no paneth cells and no microvili - COLON ONLY HAS CRYPTS
-small intestine has paneth cells, crypts and microvili |
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Proliferating cells are stained brown with the cell cycle marker
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Ki67
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Ki67
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Proliferating cells are stained brown with the cell cycle marker
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What is the heirachy of HSC ?
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-start out with multipotent HSC
-HSC makes progenitor myeloid cells & progenitor lymphoid cells |
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CSF
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-colony stimulating factors, it's what cause there to be 100X more erythrocytes than basophils for instance.
-regulates the probability of cell division & death for each pathway |
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What are CSF controllable parameters?
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-frequency of stem cell division
-probability of stem cell death -probability that stem cell daughter will become a committed progenitor cell of a given type -division cycle time of committed progenitor cell -probability of progenitor cell death -number of committed progenitor cell divisions before terminal differentiation -lifetime of differentiated cell |