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22 Cards in this Set
- Front
- Back
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Why are the paramesonephric ducts allowed to develop in female embryos?
What do these ducts give rise to? |
Lack of Anti-Mullerian Hormone
Paramesonephric ducts give rise to fallopain tubes (upper portion of ducts), uterovaginal primordium (from lower fused portion of ducts; forms uterus and upper vagina) |
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What is the purpose of the ovary?
What occurs in it? |
Contains follicles that house developing oocytes.
Beginning stages of oogenesis occur in ovary. |
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Describe the steps of oogenesis that occur within the ovary.
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Oogonia (Primordial Germ Cell) housed in Primordial Follicle (2N)
to Primary Oocyte ARRESTED IN Prophase I |
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What cell layer surrounds the oocyte? What receptors does it contain?
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Zona pellucida
Contains species-specific ZP protein (sperm receptors) |
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What is the effect of FSH on a Primary Oocyte?
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Granulosa cells enlarge, proliferate
Two distinct layers form: theca interna and theca externa Theca Interna and Granulosa cells produce Estrogen (targets endometrium) End result is Primary Oocyte housed in a larger follicle (follicular granulosa; secondary follicle) Secondary folicle housing a PRIMARY oocyte |
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What occurs after formation of a Primary Oocyte?
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Mature follicle = Graafian or Tertiary Follicle
Surge of LH (ovulation begins) causes Graafian follicle to rupte and oocyte is released. Now completes Meiosis 1. Oocyte is now a Secondary Oocyte (N, 2C) and arrests in metaphase II Theca granulosa and theca luteum remain behind to form CORPUS LUTEUM, which produces estrogen |
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How would you identify a mature follicle?
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Large antrum with follicular fluid
Eccentrically placed oocyte |
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If, after ovulation, fertilization does not occur, what happens?
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Negative feedback to hypothalamic-pituitary axis represses LH production.
LH maintains corpus luteum during pregnancy, thus, corpus luteum breaks down to form corpus albicans, which is gradually phagocytosed. |
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How does the corpus albicans compare to the corpus lutem on slides?
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Corpus albicans is pale; nuclei have degenerated
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What occurs during the follicular phase of the menstrual cycle? Describe hormonal levels.
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Follicle development
Low FSH, Low LH Proliferation of endometrium under influence of Estrogen Endometrial glands elongate due to estrogen |
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What occurs during the luteal phase of the menstrual cycle? Describe hormonal levels.
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LH surge prior to luteal phase
Corpus luteum secretes Progesterone which stimulates further development of glands and arteries; stimulates secretions Lack of estrogen/progesterone at end of luteal phase results in ischemia; BV's pinch off and tissue sloughs (menstruation) |
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Luteal phase AKA?
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Secretory phase
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Follicular phase AKA?
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Proliferative Phase
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Describe the layers of the uterus.
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Endometrium
Myometrium (muscle layer) Serosa (over superior organ surface) Adventitia (inferior organ surface) |
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Describe the layers of the endometrium.
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Stratum basalis: simple tubular glands, straight vessels
Stratum functionalis: elongated, coiled, engorged glands and coiled arteries |
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What sublayer changes occur in the endometrium following menstruation?
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Glands of stratum functionalis are shed, leaving stratum basalis for a new cycle
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What is the epithelium of the endometrium?
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Simple columnar
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What is the function of the oviduct?
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Oviduct = Fallopian tube
Transports oocyte to uterus for further development and implantation Oviduct is lines with ciliated epithelium and each terminates near an ovary, forming fimbriae |
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Where does fertilization usually occur? What events occur?
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Usually occurs within Fallopain tube
Sperm penetrates CORONA RADIATA Undergoes ACROSOMAL RXN at zona pellucida Penetrates zona pellucida Fuses with oocyte membrane Sperm head enters membrane Male and female pronuclei fuse Egg is ACTIVATED Polyspermy prevented by physiological barriers |
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What cell process begins once fertilization occurs?
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Cleavage: series of rapid mitotic divisions resulting in morula, then blastula
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What are the main parts of the implanting embryo? Describe each.
Which produces HCG? Purpose of HCG? |
Inner cell mass (embryo's body)
Trophoblast (extraembryonic tissue that implants and forms placenta) Syncytiotrophoblast: secretes enzymes necessary for invasion of endometrium and HCG that maintains corpus luteum Chorionic villi "root" into endometrium and surrounded by maternal blood. Constitutes placenta. |
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What two layers comprise the placenta?
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Chorioamniotic membrane (fetal side)
Decidua (uterine lining; maternal side) Between the membrane and decidua, chorionic villi are bathed in maternal blood. Fetal and maternal blood DO NOT mix. |
