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EvaRL EvaRL
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10 years ago
when the uterine wall is thickened, where does all this thickness and extra blood vessels come from?
(another question I have: is the amniotic sac formed from the babies tissue?)
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10 years ago
The endometrium changes throughout the menstrual cycle in response to hormones. During the first part of the cycle, the hormone estrogen is made by the ovaries. Estrogen causes the lining to grow and thicken to prepare the uterus for pregnancy. In the middle of the cycle, an egg is released from one of the ovaries (ovulation). Following ovulation, levels of another hormone called progesterone begin to increase. Progesterone prepares the endometrium to receive and nourish a fertilized egg. If pregnancy does not occur, estrogen and progesterone levels decrease. The decrease in progesterone triggers menstruation, or shedding of the lining. Once the lining is completely shed, a new menstrual cycle begins.
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