Female reproductive system/fertilization Flashcards
What regulates the menstrual cycle?
a hormonal feedback loop involving the hypothalamus, anterior pituitary gland, and ovaries
What hapens during the follicular stage?
Follicle stimulation hormone stimulates a follicle in the ovary to mature. As follicle matures, the surrounding cells produce estrogen
after 14 days, estrogen in blood reaches a concentration that causes luteinizing hormone to be released, which causues mature follicle to release ovum into the fallopian tube.
what is the luteal phase?
After ovulation, the follicle forms into a structure called corpus luteum. Luteinizing hormone causes corpus luteum to release progeseterone and estrogen. If ovum isnt fertilized in 14 days, the corpus luteum degenerates, and the cycle repeats
What is menstruation?
after corpus luteum has disintegrated, low levels of estrogen and progesterone cause uterline lining to slough off. This is the first day of the cycle.
What is the proliferation phase?
As follicle matures, estrogen levels rise and a new uterine lining builds.
What is the secretory phase?
progesterone causes blood vessels to grow within uterine lining.
where do egg and sperm unite?
as the egg is going from the fallopian tubes to the uterus, it may encounter sperm. If sperm penetrates egg, it forms a diploid zygote.
What happens after a zygote forms?
A ball of cells called morula forms, which implants itself in the uterus. Human chorionic gonadatrpin hormone is released, which stops the corpus luteum from disintegrating. The uterline lining thickens, and estrogen/progesterone is produced until placenta takes over after three months.
What happens to the morula?
it hollows out into a spherical ball of cells called the blastula, which has a cell wall called the trophoblast. Cell differentation begins!
-The cells of the inner cell mass will form the embryo, and the trophoblast will form the membrane that surrounds ebryo.
What is the placenta?
large structure that supports develping embryo
- the blood vessels of the placenta come into close contact with mothers blood vessels.
- placent is connected to circulatory syste of the embryo through the umbilical cord
What are the four membranes that surround, nourish, and protect the embryo?
- the yolk sac provides stored nutrients. It is very small in mamals
- the amnion cushions the embryo
- the allantois is the site of waste disposal
- the chorion forms the placenta.