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19 Cards in this Set
- Front
- Back
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oogenesis |
species specific oogoniz are self renewing or limited polar bodies go through apoptosis eventually in some |
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polar bodies |
meiosis creates a totipotent egg and two polar bodies in humans, chromosomes no centromeres serve as site for spindle formation - error prone system |
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what do polar bodies become? humans? scale insects? parasitic wasps? |
humans: disease assessment scale inscets: bacteriome wasps: wrap around embryos other... parthenogenesis, endosperm |
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ovulation |
1. stimulated by copulation (rabbits) 2. periodic -estrus cycle light stimulates the brain, releases GRH and then FSH and LH these cause ovarian follicle cells to proliferate and secrete estrogen - hormonal behavior |
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ovarian follicle |
periodically a group of follicles enter a growth stage granulosa cells increase to many layers |
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Number of germ cells in ovary |
1000 oogonia around birth, most die at birth the rest become primary oocytes through meiosis |
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Regeneration |
the ability of some organisms to recreate organs and limbs that have been removed or lost |
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Aging |
time related deterioration of the physiological functions necessary for survival and reproduction |
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Different species have different regenerative capabilities |
eg. mice - liver and digits salamander - basically er'thang |
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Four mechanisms of regeneration |
EPIMORPHISIS: Dedifferentiation and respecification MORPHALLAXIS: Repatterning of existing structures COMPENSATORY REGENERATION: intermediate SC MEDIATED: regrowth |
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Epimorphosis |
salamander limb reconstruction forms only missing parts and no more "knows" where has been severed dedifferentiation, proliferation, respecificaiton |
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After amputation |
a plasma clot forms wound epidermis covers - proliferates to form AEC - apical ectodermal cap (mammals would form scars and dermal closure) dedifferentiation, proliferation, then regeneration blastema then redifferentiate |
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Prolifferation signalling |
FGF8, FGF10, Wnt3a Fgf2- angiogenesis and mitosis promotor Shh Nerves release newt anterior gradient protein and glial gowth factor GGF |
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If blastema is denervated |
forms smaller elements because of less mitosis - AEC depends on nerves for proliferation but not morphogenesis |
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RA |
synthesised by wound epidermis forms PD AP gradient activates prolifferation, down regulates differentiation causes cells to respecify at a more proximal position - limb duplication if lab induces it |
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blastema consists of restricted progenitor cells as |
cells retain their specification and commitment muscle- muscle dermal-dermal cartilage- cartialge or dermal |
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Compensatory regeneration of the mammalian liver |
remove a liver lob - remaining tissue enlarges to compensate no dedifferentiation, only proliferation each type of liver cell retains origional function hepatocytes - first in regeneration |
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After removing lobe, hepatocytes are connected to eachother and can respond to morphogens |
kupffer and stellate appear to monitor liver size stellate cells release hgf, scatter factor and tgfb mellaproteases digest ecm loosening of hepatocytes, return to cell cycle and proliferation |
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second level of liver regeneration |
if hepatocytes fail to regenerate oval cells proliferate can produce hepatocytes and bile ducts |
