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Female Reproductive system: Ovary Uterus Mammary glands. Ovary - hormonal regulation - - follicular development - Graafian follicle - corpus luteum. Germinal epithlelium Tunica albuginea is DCT and bv. In the Ovary: Stromal tissue Primary oocytes Follicular cells.
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Female Reproductive system: Ovary Uterus Mammary glands
Ovary - hormonal regulation - - follicular development - Graafian follicle - corpus luteum
Germinal epithlelium Tunica albuginea is DCT and bv
In the Ovary: Stromal tissue Primary oocytes Follicular cells
Ovarian follicles - primordial follicle - primary follicle - secondary follicle - Graafian follicle - corpus luteum
Primordial follicle - primary oocyte (prophase or meiosis I) and simple squamous follicular cells
Primary follicle (unilamellar/multilamellar) - enlarged oocyte (nucleus up to 150 mm) - simple cuboidal follicular cells --> stratified cuboidal --> granulosa cells Activin from primary oocyte granulosa cell proliferation
Primary follicle • Zona pellucida – amorphous substance between oocyte and follicular cells • - contains follicular cell filopodia and oocyte microvilli. • - gap junctions between oocytes and follicular cells • Stroma cells: • theca interna -vascularized, have LH rec. • secrete androstenedione in response to LH • andr. Crosses basal lamina & enters granulosa cells • aromatase estradiol released by the granulosa cells • theca externa (fibrous)
Secondary (antral) follicle • -FSH stimulates granulosa cell proliferation (and LH receptors on the granulosa cells) • -liquor folliculi between granulosa cells • antrum is space with coalesced liquor folliculi With steroid binding proteins, steroid hormones etc. • Cumulus oophorus – granulosa cells in the antrum attached to the granulosa cells on the wall • Granulosa cells around the zona pellucida remain attached to the oocyte by filopodia corona radiata • o
Secondary (antral) follicle Some become graafian Most secondary follicles become atretic follicles become interstitial glands Small amounts of androgens
Granulosa cells • Nourish oocytes • Secrete antral fluid • Bind FSH • Secrete estrogen, inhibin, • Bind LH to start changes that lead of ovulation
Effects of LH • Oocyte, meiosis completion, cytoplasmic changes for implantation (messengers released by granulosa cells) • Increase antral size • Granulosa cells secrete prostaglandings, lower estrogen, prostaglandins breakdown tissue
Graafian follicle: - can see on slide with unaided eye (up to 1 inch) - cumulus oophorus: oocyte +corona radiata + attached follicular cells detach and float in the liquor folliculi LH surge --> increased blood flow to ovaries --> edema (leaking plasma) in theca externa also: completion of meiosis I and then meiosis II --> ovulation and some follicle cells
Ovulation: • All of the granulosa cells are making lots of estrogen • High blood estrogen • Negative feedback inhibition on FSH from AP AND sudden LH surge from AP • • 1. Increased blood flow to ovaries • --> edema (leaking plasma) in theca externa • 2. Around Graafian follicle, histamine, collagenase, PG • 3. Completion of meiosis I and then meiosis II • --> small region of tunica albuginea looses bl supply • Opening to peritoneal cavity • ovulation with some follicle cells
ovulation --> small region of tunica albuginea looses bl supply • Opening to peritoneal cavity • ovulation with some follicle cells • Remaining follicle becomes corpus luteum because LH levels remain high
Corpus luteum: temporary endocrine gland for uterine endometrium Continued high LH Collapse of remaining Graafian follicle --> granulosa lutein cells produce progesterone & convert androgens to estrogen --> theca interna---> theca lutein cells produce progesterone, androgens & estrogen
During Corpus Luteum: High levels of progesterone & estrogen --> LH and FSH secretion inhibited --> lower FSH prevents follicular dev. If pregnancy occurs, placenta secretes human choriogonic hormone (HCG), which maintains the corpus luteum.
Summary of hormonal regulation of ovarian function: GnRH FSH and LH Apparently independent of FSH, Activin from oocyte causes proliferation of granulosa cells. FSHmultilamellar primary follicles to secondary follicles, - binds onto granulosa cells make estrogen - binds onto theca interna cells make LH receptors
LH: • Theca interna cells make androgensAndrogens enter granulosa cellsAromatase converts to estrogen Granulosa cells also make: • inhibin, folliostatin, activin feedback onto AP to regulate FSH release (inhibin inhibits FSH release) • Estrogen from granulosa cell • Rise in blood estrogen • Negative feedback onto FSH release and GnRH release AND stimulates AP release of LH ovulation
LH • Granulosa cells and theca interna cells form CL For 14 days, CL cells -(mostly granulosa-lutein cells) synthesize progesterone • synthesize negative feedback hormones on FSH secretion • (inhibin, folliostatin, activin) • Progesterone • dev. Of uterine endometrium And neg feedback on LH secretionCL degeneration If pregnancy: Placental hCG keeps CL secreting progesterone