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37 Cards in this Set

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What is regeneration?
Prolif of cells & tissues to replace lost structures. (eg liver, hematopoetic cells, skin, & epi of GI tract)
What is repair?
A hybrid of regeneration & scar formation w/ some restoration & some structural derangement
What is scar formation?
Deposition of collagen
What are the completely renewing tissues?
Blood, skin, & epi of GI
What is the normal homeostasis of healing?
A balance of prolif, differentiation, & cell death
What are the 3 groups of tissue prolif activity?
Labile, Stabile, & Permenant tissues
What are labile tissues? Examples.
Continuously divide throughout life span. (eg stratified squamous epi of skin, oral, vagina, cervix. Lining of glands, columnar epi of GI, Uroepi of urinary trat. Bone marrow & hematpoietic system
What are stabile tissues? Examples.
Quiescent; low level of replication only when need to. Rapid division in response to stimuli. (eg Parenchymal: liver, kidney, pancreas. Mesanchymal: fibroblasts & smooth m. WBC & vascular endothelial cells
What are permanent tissues? Examples.
Non-dividing; cells no longer in cell cycle postnatally. (eg neurons, skeletal m, cardiac m)
What are the charac of stem cells?
Self-renewal & capacity to generate differentiated cell lineages
What are the 2 mech of stem cell maintainence?
Obligatory assymetric replication & stochastic differentiation
Charac ofobligatory assymmetric replication?
With ea division, 1 cell retains self-renewal capacity & the other enters a differentiation pathway
Charac o stochastic differentiation?
Balance b/w 2 division processes: 1) those which make 2 self-renewing stem cells & 2) those which make 2 cells that differentiate
What are emryonic stem cells?
Pluripotent cells from the inner cell mass of blastocyst. Can differentiate into any cell type. Used to make knockout mice. Hoped to repopulate damage organs
What are the 2 types of cloning?
Induced pluripotent & therapueutic cloning.both are inefficient & inaccurate
Charac of induced pluripotnet stem cells.
Differentiated cells are pregrogrammed by transfering nuc of adult stem cell into enucleated oocyte. Use surrogate mother to clone embryo
What is therapeutic cloning?
Nuclear transfer into oocyte for treatment of human diseases. Take nuc from skin fibroblasr + human oocyte-> embryonic stem cell in culture
Why is cloning inaccurate?
Deficiency in histone methylation in reprogrammed embryonic stem cells, which results in improper gene expression
What are the charac of adult/somatic stem cells?
Present in tissures which contin divide. (skin, bone marrow, linig of GI)
What stem cells are important in regeneration & maintainence?
bone marrow, liver, brain, skin, cornea, intestinal epi, skeletal, cardiac m
Where are stem cells located in the skin?
Hair follicle bulge, sebaceous glands, & interfollicular area of surface epi
How is replication stim?
Growth factors & signaling from EC matrix via integrins
How is cell cycle progression regulated?
Cyclins, CDK, catalytic activation, phosphorylation, inhibition
What is the importance of cell cycle check points?
Sense DNA & chrom damage, not allow damaged cells to contin, G1/S checks before preplication, G2/M checks after replication. Apop or senescence if damaged
What are growth factors?
Polypeptides that re ligands w/ specific receptors->stim transcription of genes
How are EGF & TGF-alpha similar?
Share a common receptor. EGFR is a family of 4 receptors w/ intrinisic kinase activity. ERB B2/Her2 overexpressed in breast cancer
Fcn of HGF?
Mitogenic effect on hepatocytes & mose epi cells. Required for survival during embryonic development
Fcn of PDGF?
3 isoforms, sored in plts & released upon plt activation
Fcn of VEGF?
Induces blood vessel formation. Promotes angiogenesis in chronic inflammation, wound healing, & tumors
Fcn of FGF?
Involved in wound repair, hematopoiesis, development
What are te 3 signaling mech?
Autocrine (liver & tumor), paracrine (wounds-fibroblasts & macros), & endocrine
What are the 4 types of receptors?
Intrinisic kinase activity, extrinsic kinase, G-protein, & steriod hormone receptors
Charac of intrinisic kinase receptors?
Most GF, extracell ligand binding domain, transmembrane region, cytoplasmic tail w/ kinase activity. (alterations in activity-> cancer)
Charac of extrinisic kinase receptors?
Many cytokines, GH, prolactin. Transmit signals to the nuc via JAKs
Charac of G-protein receptors?
Transmit siganl through trimeric GTP-binding proteins, act vis conformational changes, cAMP as 2nd messenger. 7 transmembrane alpha helices, targeted by many drugs
Charac of steroid hormine receptors?
Located in nuc, fcn as ligand-dependent transcription factors. (thyroid hormone & Vit D)
Charac of transcription factors?
Fcn in heterodimer formation, phosphorylation, & release inhibition. Cellular events requiring rapid responses rely on post-translationsl modification