Female Reproductive Physiology Flashcards
What are the main components of the female reproductive system
uterus, fallopian tube, ovary
What is the main difference between males and females when it comes to sex cell formation in fetal development
in males mitosis continues throughout out adulthood-always have production of new sperm cell cells because the spermatogonia that doesn’t go through meiosis continues to divide
in females, mitosis only occurs in embryonic life- the primary oocyte at meiosis 1 will stop and resume at meiosis 2 only if it selected after puberty
Oocytes
these are also known as eggs. the female sex cells
How are oocytes produced?
During fetal development, the primordial germ cells will go through mitosis many times- oogonia (the end result of mitosis)
2. oogonia will enter meiosis 1, duplicate their DNA and stop- at birth females have their primary oocytes
3. After puberty one primary oocyte completes meiosis 1 and enters meiosis 2 to become secondary oocyte every 28 days
4. the secondary oocyte will only complete meiosis 2 if the oocyte is fertilized.
What happens if the oocyte is not fertilized?
it will die 12-24 hours after ovulation
What is the outline of oocyte maturation
primary follicles surround the oocytes and every 28 days 5-10 follicles are recruited but only one will move to full maturation
- primary follicle
- secondary follicle
- early tertiary follicle
- dominant follicle
- the follicle will rupture releasing the oocyte
What happens to the oocytes that do not reach full maturation
they undergo atresia- hormonally regulated cell death
Role of Granulosa cells
immediately surround the oocyte and helps with its development
Role of Theca Cells
secrete steroid hormone precursor
what are the components of the menstrual cycle?
ovarian and uterine cycles
What 2 phases make up the ovarian phase?
Follicular phase and luteal phase
Steps in the ovarian cycle
- small number of primordial follicles develop
- becomes a primary follicle with theca and granuloma cells. theca cells synthesize androgens which are converted into estrogens in granulosa cells
- some follicles develop to secondary follicles
- Structure becomes tertiary follicle
- dominant follicle (Graafian) develops
- Graafian follicle ruptures releasing oocyte and ovulation begins
- the oocyte will jump to the fallopian tube and Cumbria will capture oocyte and move it to uterus
- the follicular cells left behind will become corpus luteum- which releases progesterone and estrogen
- if fertilization does not occur, corpus luteum degenerates
if fertilization occurs, the corpus luteum continues to make progesterone and estrogen until the end of the first trimester
What is the scar tissue of the degenerated corpus luteum called?
corpus albicans
What is the LH surge? when does this happen?
the LH surge occurs during the follicular stage when the follicular cells release collagenase (digest the connective tissuee at the end of the ovary) and progesterone (facilitate expulsion of oocyte by causing smooth muscle contraction)
Luteal phase
the ruptured follicle will turn into corpus luteum and will regress- its fate will depend on whether the oocyte becomes fertilized
when does the ovarian cycle occur?
during days 14-28
Uterine Cycle
blood vessels in the endometrium undergo constriction that causes shedding of the endometrial lining
Endometrium
inner lining of the uterus that contains blood vessels
Why does the inner lining of the endometrium shed?
due to declining levels of progesterone and estrogen, which are signs of no fertilization
no fertilization means that the thickened part of the endometrium is no longer needed
What is the proliferative phase of the uterine cycle
this is where the endometrium develops in response to estrogen. the endometrial lining thickens as blood supply to tissues is re-established
what is the secretory phase of the uterine cycle
glands in the endometrium secret viscous fluid. endometrial cells deposit lipid and glycogen in cytoplasm under the influence of progesterone and estrogen
what are the three phases of the uterine cycle
- menstrual phase
- proliferative phase
- secretory phase
how are the ovarian and uterine cycles integrated and overlap
- when the follicle is growing so does the endometrium
- as we enter the luteal phase of ovarian cycle, the endometrium continues to expand and thicken in preparation for a fetus
- if there is no fertilization, corpus albican signals to the endometrium to start shedding because there is no
what are the estrogen and progesterone levels during the follicular, menses and proliferative phases
in this phase, this is where the follicle is growing, so estrogen is triggered but progesterone stays low
what are the estrogen and progesterone levels during the luteal and secretory phase
at the end of the follicular phase estrogen drops and progesterone starts to spike due to the corpus luteum as a way to help the potential fetus
estrogen also starts to see a slight increase from the corpus luteum
how is the menstrual cycle regulated?
by GnRH, FSH, and LH
how is the role of LH different between males and females
in males it is only FSH that contributes to gamete production, however in females LH and FSH contribute to gamete production
What hormones are impacted or triggered during the early follicular/ menses phase
gonad hormone levels: both FSH and LH levels are low
there are some follicular formation
ovarian hormone levels: estrogen is high and inhibin and progesterone is low
uterine cycle: menstruation and shedding of endometrium
what exactly is happening during the early follicular/menses phase?
LH stimulates the release of androgens from the theca cells
FSH converts estrogen from granulosa cells
granulosa cells secrete AMH to prevent the recruitment of additional follicles
estrogen exerts positive feedback on granulosa cells, increasing proliferation and estrogen
estrogen exerts negative feedback on hypothalamus/pituitary- which shuts down FSH and LH
in the early follicular phase, why would is the negative control on FSH and LH not a bad thing?
because the granulosa cells are able to produce their own estrogen at this point
What exactly happens during the late follicular/proliferative phase?
(Day 5-14)
Tertiary follicle is present
follicular cells secrete inhibin, estrogen, and progesterone
inhibin inhibits FSH because we don’t really need it
progesterone increases pituitary sensitivity to GnRH- which increases LH levels
High estrogen increases frequency of LH
In this phase we experience an LH surge that triggers the completion of meiosis 1 and ovulation
hormones impacted by the late follicular phase/ proliferation
LH: strong increase
GnRH: High increase
estrogen and progesterone: increase
inhibin: increase
FSH: decreased
What happens during the early to mid luteal phase
after day 14, LH drops
Progesterone, estrogen, and inhibin increases
negative feedback of the previous hormones on hypothalamus and GnRH
What happens during late luteal phase
corpus luteum undergoes apoptosis if egg not fertilized
progesterone and estrogen levels fall
GnRH and hypothalamus activity begins again and LH and FSH release
what is menopause
the ovaries are unable to respond to LH or FSH
estradiol and progesterone levels fall
lack of negative feedback causes FSH and LH to rise
how do birth control pills work to prevent pregnancy
they contain both progesterone and estrogen which when increased in the body, will cause negative regulation of GnRH and hypothalamus which will inhibit FSH and LH, preventing follicular maturation
