Physio 2 - Repro 2

drraythe's version from 2015-06-09 01:46

Female- Repro Cycles

Question Answer
What centers does the female's hypothalamus contain?tonic and Surge centers
What does the tonic center do?(one guys have too) spontaneous basal GnRH secretion in pulses of 1.5-2 hours. (males is 2-6hrs), which stim pulsatile release of gonadotropins 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 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
estrous vs estrus?rous= adjective. rus= noun.
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 examples?cow, pig, human. continuous cycles throughout the year.
what is seasonally polyestrous? examples?horse, cat, sheep, wild rumi's. continuous cycles during a certain season only, followed by a silent period.
what is monoestrous? examples?dog. one cycle occurs, followed by a silent period.
what is anestrus? caused by?period without estrous cycles (silent period) caused by pregnancy, photoperiod, lactation, "stress"
estrous 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. The ESTROGEN leads to SEXUAL RECEPTIVITY (ESTRUS), and 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)
super brief follicular phase description?proestrus and estrus--> folliculogenesis and ovulation
super brief luteal phase decription?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
purpose of the estrous cycle? (4)(1) release single/mult ova ready for fertilization (2) coodinate ovulation and copulation (3) prepare uterus for attachment (4) to switch over to preg state or start new cycle
*look over estrous cycle chartugh
when is progesterone high? when is estrogen high? Low?prog high during diestrus, estrogen high during estrus. (estrogen low during diestrus, prog low during estrus)
early follicular phase aka?proestrus
during proestrus, which hypothalamic center(s) release what? which stimulates what to happen?both TONIC and SURGE release basal pulses of GnRH. GnRH--> LH+FSH release.
during proestrus, what does FSH+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-stimed 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?Theca cells stim by LH to make testosterone. Granulosa cells stim by FSH to make T into estrogen. Stim of these gronadotropin products (estro and T) cause Theca cells to express more LH receptors and Granulosa cells to express more FSH receptors. This leads to fast inc in estrogen conc which leads to courtship b/h (but not mating b/h yet)
what phase is estrogen made in, and what is required to make it?made in PROestrous, so can be highest in ESTRUS. needs LH-->theca-->Test. and then FSH-->Granulosa-->Test. into ESTROGEN.
Exponential inc in estrogen induces what three events?(1) ESTRUS (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)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? made by 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, estro. reaches CRITICAL THRESHOLD and activates the SURGE CENTER to release surge of GnRH--> MASSIVE AMT OF LH MADE (not FSH, 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) stims local production/release of histamine, proteolytic enzymes, and prostaglandins E2 and F2alpha.
LH surge- 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 test/estro/inhibin they had been. This means estrogen dec rapidly, and estrous b/h declines. progesterone inc slowly.
LH surge- what happens when the surge blocks the meiosis INHIBITING factor?the oocyte, which was frozen, now continues 1. meiosis
LH surge- stims 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--> rupture of mature follicle w/release of oocyte into abd. cavity.
What does the LH surge lead to? (two words)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.
examples of induced ovulators? how do you guarantee 100% ovulation in these? what happens if there's no copulation?cats, camels, ferrets, minks, rabbits. several copulations to get 100% ovulation. W/o copulation--> no LH surge--> no ovulation--> 3* follicles becomes atrophic.
explain what a corpus hemorrhagicum isafter ovulation, follicular walls collapse and some bleeding occurs--> antrum fills with a blood clot= C.H.
luteal phase- what is the start of metestrus?lack of estro. abolishes estrous b/h--> end of estrus, so start of metestrus.
luteal phase- when does diestrus begin?corpus hemorrhagicum gradually luteinizes into the corpus luteum. This is the start of diestrus
what does the corpus luteum contain? What are the cells from?some fat, and the two kinds of mature lutein cells- Small lutein (from theca cells) and Large lutein (from granulosa cells) cells.
during which part of the corpus luteum phase is smal lut. cells active? large? what do both types of luteal cells make, and why?small= early CL phase. large=late CL phase. both produce PROGESTERONE, because it prepares the endometrium for a potential pregnancy.
how do progesterone levels affect the hypothalamic centers?inc progesterone will lower but NOT inhibit the tonic/surge centers--> GnRH released in low frequency/low amplitude pulses-->low level pulses of LH and FSH
during the luteal phase, what is LH doing?it keeps the corpus luteum viable.
what are the LH and FSH pulses doing during diestrus?they are lowered because of the inc progesterone levels, but are still sufficient to initiate folliculogenesis during diestrus (called follicular waves)
what happens with follicular waves (low level GnRH release during luteal phase) in polyestrous domestic animals?pulses induce cohorts of 1* follicles to grow (RECRUITED FOLLICLES), and many becomem atretic. some may start to produce estro again (selected follicles) and many become atretic. 1/several (mono/polytocous) recruited follicles grow to antral follicles (dominant) and produce lots of estrogen, but only if they are not in the presence of progesterone (so, not in diestrus) will this lead to an LH surge (b/c progesterone inhibits surge center) so only after luteolysis can the surge respond to the recruited/selected follicles estrogen conc.s
end of diestrus/luteolysis in LIVESTOCK..not preg. what happens?uterus starts to produce PGF2alpha, which reaches ovary via uterine vein/ovarian artery (bypass lung metabolism) and the PG F2alpha leads to APOPTOSIS of luteal cells--> CL regression--> progesterone dec= end of diestrus
end of diestrus/luteolysis in primates/carnivores. Not preg, what happens?PGF2alpha produced by CL!! (NOT UTERUS LIKE IN LIVESTOCK.). so then the PGF2alpha causes apoptosis of CL cells and dec of progesterone= end of diestrus
so diestrus ends as progesterone dec-- how does the cycle start again?proges no longer inhibiting the tonic/surge centers, so their basal pulses increase back to regular levels of freq and amplitude--> inc FSH/LH--> proestrus
what does oxytocin have to do with luteolysis? (comes from where for who, and does what?)oxy from large luteal cells in livestock, oxy from post pituitary in primates/dogs. OXY INITIATES THE PG F2alpha release!
in luteolysis, what initiates release of PGF2alpha?oxytocin
what is going on with sheep and oxytocin/luteolysis?the oxy and PGF2alpha are released in pulses
when is the only time luteolysis can occur, and what makes this limitation possible?PGF2alpha receptors only high in LARGE luteal cells, which are the LATE diestrus luteolysis can only occur during late diestrus
what if you are a doc, and you want to make luteolysis happen?you can inject exogenous PGF to induce luteolysis, but it's only effective during mid-late luteal phase (b/c receptors only on Lg. luteal cells)
how can an endometritis cause a permanent anestrus/diestrus? in who?in rumi/pigs (NOT MARE) the endometrium would be the thing to produce the PGF2alpha, but it is diseased, so it doesnt produce the PGF2alpha, so no luteolysis is stim, so permanent CL continues to release progesterone--> stay in diestrus
Why would you want to induce luteolysis in vet med?for early gestation, abortion, parturition, synchronize herds, rid uterine infections (contraction of uterus helps move out infection)
what would happen if you injected progesterone into an animal? why would you do that?would stop regular cycle/encourage diestrus. Use as a birth control to prolong the cycle, keeping the animal from going into heat, to synchronize herds, or to maintain pregnancy
What is happening to the endometrium during follicular phase? (pro+estrus)PROLIFERATIVE PHASE. under ESTROGEN, prolif of the endo. inc thickness, hyperemia and swelling of vulva, endometrial and cervical glands secrete thin, string-forming mucus.
what is happening to the endometrium during luteal phase? (met+die)SECRETORY PHASE (biggest here). under PROGESTERONE growth of spiral arteries--> inc blood supply--> swelling of endo. with inc secretory activity, accumulation of nutrients (uterine milk)--> READY FOR IMPLANTATION/ATTACHMENT
what happens to the endometrium during the luteolytic phase?MENSTRUATION/REGRESSION. luteal phase--> BVs vasospastic--> necrosis of endometrium. in primates, this leads to desquamation/external bleeding (menstruation). other domestic animals absorb rather than desquamate their endometrium, either way they are regressing.
what is happening when a dog has external bleeding?NOT menstruation, it's massive prolif of BVs during PROLIF phase will cause some bleeding.
effect of estrogen on overall animal?growth/maintenance of primary and secondary female sex charateristics
effect of estrogen on uterus?prolif of endometrium, mucus
effect of estrogen on oviducts?prolif of glandular tissue and CILLIATED CELLS, INC CILIA ACTIVITY
effect of estrogen on vulva/vaginahyperemia, swelling, mucus
effect of estrogen on mammary glanddeposition of fat, prolif of stroma and duct system
effect of estrogen on skeletonINC OSTEOBLASTIC ACTIVITY and mineralization (so during menopause, dec in this causes possible osteoporosis)
effect of estrogen on metabolismslight inc protein synth, inc fat deposition/ SQ tissue
effect of estrogen on b/h?initiates sexual receptiveness
effect of progesterone on uterus?stim secretory activity of endo. glands, dec myometrial activity= progesterone block
effect of progesterone on mammary gland?develop mammary lobule and alveoli

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