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27 Cards in this Set
- Front
- Back
3 major endometrial cycles |
menstrual, proliferative and secretory phases |
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what causes menstrual phase |
high levels of E&P suppress LH levels, diminishing CL. Degeneration of endometrium occurs |
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what causes proliferative phase |
estrogen produced by follicle development |
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what causes secretory phase |
The rise of E triggers LH surge. This surge triggers CL to produce P and E. |
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after menstruation, what happens to endometrium |
it is restored by proliferation of epithelial and stromal cells. |
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what drives the proliferation of cells that make up endometrium |
estrogen secreted by granulosa cells of developing follicles |
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what happens during early secretory phase |
P stimulates secretory changes in tissue |
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what happens in middle to late secretory phase` |
endometrial glands become filled with secretions. Lasts 20 days. |
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what are the events in pregnancy |
fertilization, implantation, placentation, and parturition |
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what happens to fertilized ovum |
stays in fallopian tube for 3 days and becomes morula |
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define preimplantation |
the morula enters uterus and stays free floating for 72hrs. embryo is nourished by uterus that makes proteins |
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what role does endometrium play in preimplantation |
it only has a 19-23 day window that it is receptive; receptivity controlled by hormones |
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what signals does the embryo synthesize and why |
human chorionic gonadotropin- sustains CL, which is asource of progesteron immunosuppressive agents- control mothers immune response proteases- facilitate invasion of trophoblast into the endometrium |
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phases of embryo implantation |
apposition, adhesion, and invasion |
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what role does zona pelucida play in embryo hatching |
it surrounds the blastocyst degenerates brofre initiation of implantation |
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define apposition |
initial loose contact between the trophectoderm and endometrium |
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define adhesion |
adhesion of trophoblast to uterine epithelium via ligand receptor. This dislodges uterine epithelial cells from their basal lamina, making it easier to access trophoblast to basal lamina for penetration into stromal layer |
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define invasion |
trophoblast secretes secretions that simulate invasion of the endometrium and have root like projections that get blood supply |
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after invasion of the cell, what happens |
it becomes decidual cells/decidua. Needs progesterone |
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function of placenta |
carries oxygen, removes CO2 and waste from fetus |
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what happens after implantation |
syncytiotrophoblast invades stroma of uterus. Within the blasts, are lacunae, fluid filled holes. 12 days later, it connects to veins. Cytotrophoblasts create small mounds known as primary chorionic villi. They eventually become secondary chorionic villus |
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characteristics of mature placenta |
outer surface of chorionic villus is covered with thin layer of syncytiotrophoblast. Lacunae merge into one. |
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what hormones are secreted by placenta |
hCg, progesterone, and estrogen |
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what is meant with the concept of maternal placental fetal uit |
the placenta cannot make steroid hormones alone. Mother and fetus need to make em |
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what role does LDL cholesterol play |
it is converted to progesterone by placenta and sent to mother |
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what are the three enzymes that placenta lacks for estrogen biosynthesis |
fetal adrenal gland, liver supply-estrogen precursor and DHEA. |
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how doe fetus protect itself from exposure to high levels of steroid hormones |
fetus conjugates steroid hormones to sulfate to reduce activity of hormones. |