endoReproFemale Flashcards
estrogen
Essential for ova maturation and release
Establishment of female secondary sexual characteristics
Essential for transport of sperm from vagina to fertilization site in oviduct
Contributes to breast development in anticipation of lactation
progesterone
Important in preparing suitable environment for nourishing a developing embryo/fetus
Contributes to breasts’ ability to produce milk
ovarian cycle
Average ovarian cycle lasts 28 days
Normally interrupted only by pregnancy
Finally terminated by menopause
ovarian cycle phases alternating
Follicular phase
Dominated by presence of maturing follicles
Luteal phase
Characterized by presence of corpus luteum
follicular phase
• Operates first half of cycle
• Granulosa cells of some primary follicles proliferate
• Oocyte inside each follicle enlarges
• Theca cells in follicle secrete increased amounts of estrogen
Rapid follicular growth continues during follicular phase
One follicle usually grows more rapidly and matured about 14 days after onset of follicular development
Follicle ruptures to release oocyte from ovary
Event is called ovulation
Released oocyte enters oviduct where it may or may not be fertilized
luteal phase
• Last 14 days of ovarian cycle
• Old follicular cells undergo structural transformation to form corpus luteum
• Becomes highly vascularized
• Becomes fully functional within four days after ovulation
Continues to increase in size for another four or five days
• If released ovum is not fertilized and does not implant, corpus luteum degenerates within about 14 days after its formation
FSH rise signals
During follicular phase, the rise in FSH signals ovarian follicle to secrete more estrogen
Rise in estrogen feeds back to inhibit FHS secretion which declines as follicular phase proceeds
LH rises in follicular phase
As it peaks in mid-cycle, it triggers ovulation
corpus lute secretes what during luteal phase
progesterone and estrogen
Progesterone output inhibits release of FSH and LH
Low LH – corpus luteum degenerates Progesterone levels decline
FSH can start to rise again, initiating new cycle
control of ovulation and subsequent luteinazation of the ruptured follicle are triggered by…
an abrupt, massive increase in LH secretion
This LH surge brings about four major changes in the follicle:
during the ovulation..
Halts estrogen synthesis
Reinitiates meiosis in the oocyte of the developing follicle
Triggers production of locally acting prostaglandins Differentiation of follicular cells into luteal cells
LH and corpue luteum
LH “maintains” the corpus luteum; that is, after triggering development of the corpus luteum, LH stimulates ongoing steroid hormone secretion by this ovarian structure
Under the influence of LH, the corpus luteum secretes both progesterone and estrogen, with progesterone being its most abundant hormonal product
uterine or menstrual cycle
3 phases
reflects hormonal changes during ovarian cycle average 28 days - menstrual phase - proliferative phase - secretory or progetational phase
menstrual phase
discharge of blood and endometrial lining debris from vagina
First day of menstruation is considered start of new cycle
• Coincides with end of ovarian luteal phase and onset of follicular phase
proliferative phase
• Begins concurrent with last portion of ovarian follicular phase
– Endometrium starts to repair itself and proliferate under influence of estrogen from newly growing follicles
• Estrogen-dominant proliferative phase lasts from end of menstruation to ovulation
• Peak estrogen levels trigger LH surge responsible for ovulation