Physio 2 - Repro 2

isabellepjk's version from 2017-04-27 15:08

Female- Repro Cycles PreLuteal

Question Answer
What centers does the female's hypothalamus contain?Tonic and Surge centers
What is the main function of the 2 tonic and surge centers in the mature female's hypothalamus?GnRH
What does the tonic center do?Show spontaneous basal GnRH secretion in pulses of 1.5-2 hours. (males is 2-6hrs), which stim pulsatile release of FSH and LH from ant. pituitary
What does the hypothalamic surge center do?(one ONLY GIRLS have.) Shows low basal GnRH pulses (like the tonic center) until ESTROGEN reaches a CRITICAL THRESHOLD.
Then there's a massive SURGE of GnRH
What is the negative feedback control of the hypothalamic centers (tonic and surge) (2)progesterone works in two ways: (1) progesterone LOWERS PULSE FREQUENCY/AMPLITUDE of both centers. (2) progesterone INHIBITS the SURGE of the surge center
What is puberty in females define as?process of acquiring repro. competence (can support pregnancy)
What is onset of puberty in the female influenced by? (3)(1) genetic factors (breed, age) <--only factor for males. (2) threshold body weight (fat depot). (3) external factors, eg, photoperiod or social factors
How do you know about the hormonal changes going on during the estrous cycle?clinically unnoticed except for a B/H change.
What is the ESTRUS?=heat, period of sexual receptivity, standing to be mounted. (*only high primates mate at any time during the cycle)
What is polyestrous, and what are some examples?cow, pig, human. continuous cycles throughout the year.
What is seasonally polyestrous?
What are some examples?
horse, cat, sheep, wild rums.
Continuous cycles during a certain season, followed by a silent period.
What is monoestrous species?
What are some examples?
dog. one cycle occurs, followed by a silent period.
What is anestrus?
What is it caused by?
Period without estrous cycles (silent period) caused by pregnancy, photoperiod, lactation, "stress"
Estrous cycle involves periodic ovarian changes with what two major phases?
How much of the cycle does each of these phases take up?
(1) Follicular phase (1/3 of cycle) (2) Luteal phase (2/3 of cycle)
General characteristics of the follicular phase of estrous?
(phases, dominated by, what hormone leads to what, what big thing happens?)
(phases) early PROESTRUS stage and late ESTRUS phase.
(dominated by) FOLLICULOGENESIS with ESTROGEN production.
Peak estrogen levels initiate OVULATION via GnRH/LH surge (estrogen stims surge center of hypo.)
General characteristics of the luteal phase of estrous?
(phases, what big things happen, hormones, ends with what?)
(Phases) early METESTRUS and the main phase DIESTRUS.
Conversion of the OVULATED FOLLICLE into CORPUS LUTEUM with production of PROGESTRONE.
The progesterone prepares endometrium for preg.
ENDS with REGRESSION OF CORPUS LUTEUM= luteolysis (--> corpus albicans)
What is the purpose of the estrous cycle?To release a single, or multiple ova ready for fertilization (
) To co-ordinate time of ovulation with copulation
to prepare the uterus for attachment
to 'switch over' to pregnancy state or induce a new cycle
Super brief follicular phase description?proestrus and estrus--> folliculogenesis and ovulation
Super brief luteal phase description?metestrus and *diestrus (main phase)-->
make corpus luteum, end with regression of corpus luteum into corpus albicans
Which is longer, follicular or luteal phase?Luteal (metestrus and diestrus)
When is progesterone high/low?
When is estrogen high/low?
Progesterone high during diestrus, low during estrus to metestrus transition
Estrogen high during estrus, low during metestrus and diestrus
Early follicular phase aka?proestrus, which is 2-4 days in a sow
During proestrus, what happens in the hypothalamic and tonic surge centers?both TONIC and SURGE centers release basal pulses of GnRH, which stimulates corresponding pulse of FSH and LH.
During proestrus, what do FSH and LH do together?Need both to induce production of estrogen
During proestrus, what does LH do alone?stim THECA cells to make TESTOSTERONE, which diffuses into granulosa cells
During proestrus, what two things does FSH do by itself?(1) stim a GROUP of 1* follicles to become 2*= folliculogenesis. (2) stim granulosa cells to convert testosterone (from the LH-stemed theca cells) to ESTROGEN. It is then secreted and accumulated between granulosa cells--> ANTRUM forms
What is the "upregulation" during proestrus, and what does it result in?Upon gonadotropin stimulation, Granulosa cells express more FSH receptors and Theca cells expressed more LH receptors.
Results in upregulation (cells become more sensitized to gonadotropin
fast increase in estrogen leads to an increase in proestrus behavior
What phase is estrogen made in, and what is required to make it? What does it do to follicles?made in PROestrous, so can be highest in ESTRUS. needs LH--> Theca-->Testosterone and then
FSH--> Granulosa-->Testosterone into ESTROGEN.
causes explosive growth of follicles
Exponential inc in estrogen induces what three events?(1) ESTRUS (2-3 days)
(2) INHIBIN release and LH receptor expression
(3) LH surge
If you see first signs of estrus, what day of estrus are you in?
What hormone increases in estrus, and what development takes place (early estrus)?
First signs= day 1. Estrogen increases and 2* follicles turn to 3* follicles.
After estrus begins, what is released and what is expressed? What does this cause to happen? (second event in sequence after the exponential increase in estrogen)INHIBIN is released and LH receptors are expressed from the GRANULOSA cells. Inhibin selectively inhibits FSH release--> FSH dec--> slows maturation of less matured follicles in the group of follicles it originally stimulated, so only 1/a few up-regulated follicles remain active and produce estrogen.
What is inhibin? What is it made by and what to do what?A follicle in estrus has granulosa cells which release the inhibin to slow down the other less mature follicles' growth
After inhibin stops maturation of less mature follicles, what happens with the fully up-regulated follicles?They create a final increase in estrogen
Estrogen reaches CRITICAL THRESHOLD and activates the SURGE CENTER to release surge of GnRH--> MASSIVE AMT OF LH MADE (not FSH it is still inhibited by inhibin of granulosa cells). MAKES THE LH SURGE
What are the three effects of the LH surge?(1)* initiates LUTEINIZATION (turn into CL) of granulosa/theca cells
(2)* blocks the meiosis inhibiting factor
(3) stimulates local production/release of histamine, proteolytic enzymes, and prostaglandins E2 and PGF2a.
LH surge effect- what happens when granulosa and theca cells are luteinized by the LH surge?(LH surge very powerful, they all have upregulated LH receptors now too) they begin to produce PROGESTERONE instead of the testosterone/estro/inhibin they had been. This means estrogen dec rapidly, and estrous behavior declines. Progesterone inc slowly.
Both have developed LH receptor by now
LH surge effect - what happens when the surge blocks the meiosis INHIBITING factor?the oocyte, which was frozen, now continues primary meiosis
LH surge effect- Stimulates local production/release of histamine, proteolytic enzymes, and prostaglandins E2 and F2alpha. Why?causes localized inflammation which leads to follicular swelling, pressure inc, breakdown of connective tissue, causing rupture of mature follicle w/release of oocyte into abdominal cavity approximately 12-24 hours after the surge.
What does the LH surge lead to?spontaneous OVULATION! (during late estrus)
How does ovulation occur in an induced ovulator?ovulation during or after copulation, because coitus induces a NEUROENDOCRINE reflex via vaginal and cervical receptors that leads to GnRH/LH surge.
In induced ovulators, what happens if there is no copulation?There is no LH surge, therefore no ovulation and no tertiary follicles will become atrophic.
Examples of induced ovulators? How do you guarantee 100% ovulation in these?Cats, camels, ferrets, minks, rabbits.
Explain what a corpus hemorrhagicum isAfter ovulation, follicular walls collapse and some bleeding occurs--> antrum fills with a blood clot