exam 2 Flashcards
what is the definition and function of germinal epithelium?
- surface epithelium covering the tunica albuginea, is continuous with the peritoneal lining
- breaks at ovulation
what is the definition and function of the tunica albuginea?
dense CT layer; provides structure to the ovary
what is the definition and function of the cortex
outer part of the ovary; contains germ cells, oocyte population, and CL
what is the definition and function of the medulla?
central part of the ovary; contains CT, houses blood lymph, and nerve
what is the hilus?
where vessels, nerves, and ducts enter the ovary
what is the definition of polyestrus? species?
- female displays estrous cycles uniformly distributed throughout the year without seasonal influence
- cow, sow, queen
what is the definition of seasonal polyestrus? species?
- displays estrous cycles based on length of day
- ewe (short day), mare (long day)
what is the definition of monoestrus? species?
- female displays only one period of sexual receptivity
- dogs, wolves, bears
what is the difference between the mare’s ovary and other species?
- ovulation can only occur at the ovulation fossa (CL cannot be palpated)
- cortex=inside, medulla=outside
what is anestrus?
when a female does not display estrus
when would a female experience anestrus?
due to an insufficient hormone stimulus from the HPG axis (ex: poor nutrition, pregnancy, seasonal, prepubertal)
what are the stages of the estrous cycle? which are in the luteal phase and which are in the follicular phase?
- luteal: metestrus and diestrus
- follicular: proestrus and estrus
what causes ovulation?
preovulatory LH surge
what is luteolysis?
destruction of the CL
what is the dominant structure and hormone of the follicular phase?
follice, estrogen
what developing stage is gonadotropin independent? dependent?
- independent = pre-antral follicles
- dependent = antral follicle
what happens to a follicular wave under influence of progesterone?
follicles will not reach the threshold to ovulate and instead undergo atresia
what is the dominant structure and hormone of the luteal phase?
CL, progesterone
what do theca and granulosa cells transition into?
- theca cells –> large luteal cells
- granulosa cells –> small luteal cells
how are theca and granulosa cells turned into luteal cells?
lutenization
what hormones do SLCs and LLCs produce?
- LLCs: progesterone, oxytocin, relaxin
- SLCs: progesterone
what receptors do SLCs and LLCs have?
- SLCs: oxytocin
- LLCs: PGF2a
Do LLCs perform hypertrophy or hyperplasia? SLCs?
- LLCs: hypertrophy
- SLCs: hyperplasia
what are two ways luteolysis occurs?
- functional luteolysis: oxytocin is released from PP to the uterus which stimulates PGF2a from the uterus, PGF2a then binds to its receptor on LLCs which inhibits progesterone synthesis
- structural luteolysis: luteal cells can die, SLCs die first, LLCs second, and then immune cells clean up the dead cells
explain the hormone profile for the entire estrous cycle
- progesterone: levels increase and peak during diestrus, decrease during proestrus, are low through estrus, and begin to increase during metestrus
- estrogen: levels are low during diestrus, rising during proestrus, rising and peak during estrus, and decreasing during metestrus
- FSH: low pulses during diestrus, rising during proestrous, rising, peaks and decreases during estrus, and low pulses during metestrus
- LH: low pulses during diestrus, rising during proestrus, rising, peaks, and begins decreasing during estrus, and decreases during metestrus
- GnRH: (all pulses) low during diestrus, begins rising during proestrus, rising and peaks during estrus, and decreasing during metestrus
what is the difference between functional and structural death of the CL?
- functional luteolysis: decrease in progesterone production, uterine PGF2a binds to receptors on LLCs which tells oxytocin to increase (oxytocin receptors are on SLCs), PGF2a signaling results in a deacrease in LDL (low density lipoprotein) receptors on luteal cells and a decrease in LH receptors on luteal cells
- structural luteolysis: luteal cells die via apoptosis, SLCs die firs, LLCs 2nd, and then resident immune cells remove cell fragments leaving only scar tissue
name and describe the function of the 3 segments of the oviduct
- infundibulum: opening to the oviduct, funnel shape to catch ovum
- ampulla: moves oocyte through oviduct to site of fertilization, not very muscular, 1st half of oviduct
- isthmus: 2nd half of oviduct, very muscular, small diameter
what are the three portions of the broad ligament? what do they support?
- mesovarium: supports ovary
- mesosalpinx: supports oviduct
- mesometrium: supports uterus
list the tissue components of the uterine tissue and how they relate to the four layers within the rest of the tract
- perimetrium: outer, serous layer, continuous with peritoneum, blocks adhesions
- myometrium: inner circle of smooth muscle, outer longitudinal layer, performs peristalsis
- endometrium: made up of mucosa and submucosa, provides point of placental attachment, contains uterine glands
what are the four distinct concentric layers of tissue found throughout the female repro tract?
- mucosa: made up of a layer of columnar epithelium, a layer of loose CT, and a band of smooth muscle, the epithelium acts as a barrier btwn the environment of the lumen and the rest of the organism’s body
- submucosa: supporting tissue, consists of dense irregular CT, contains blood, lymph, and nerve supply
- muscularis: made up of circular smooth muscle (muscle is laid in a circular pattern allowing for changes in diameter, results in constriction of the uterus) and longitudinal smooth muscle (contraction results in shortening of the tube which propels contents, peristalsis)
- serosa: a thin layer of cells enclosing body cavities, prevents adhesions, continuous with body cavity
what are the functions of the cervix?
barrier to sperm (“bouncer of the repro tract”), transports sperm, produces mucus, reservoir for sperm, blocks bacterial invasion during pregnancy, birth cabal
what is the hormone profile of proestrus?
- estrogen: rising
- progesterone: decreasing
- FSH: rising, dips at the end
- LH: rising
- GnRH: lots of pulses that are rising
what is the hormone profile of estrus?
- E2: peaks
- P4: low
- FSH: peaks
- LH: peaks
- GnRH: peaks
what is the hormone profile of diestrus?
- E2: low
- P4: peaks
- FSH: low
- LH: low
- GnRH: low
what is the hormone profile of metestrus?
- E2: low
- P4: rising
- FSH: low
- LH: low pulses
- GnRH: low
diestrus ends with what event?
luteolysis
during what stage is the CL fully functional?
diestrus
what stage consists of lutenization?
metestrus
during which phase are behaviors observed that indicate the female is receptive to the male?
estrus
describe different types of anestrus
- apparent anestrus: failure to observe estrus or failure to recognize pregnancy that is erroneously interpreted as true standing heat
- true anestrus: a condition where a female does not cycle due to insufficient hormonal stimuli
- gestational anestrus: lack of cycling due to pregnancy
- lactation anestrus: many mammalian species experience anestrus while nursing their young
- nutritional anestrus: negative energy balance due to low intake of energy or protein (causes lack of GnRH pulses which)
- environmental anestrus: can be due to length of daylight, temperature, or moisture
what are the two differences between the menstrual and estrous cycles?
- menstrual cycle is 50/50 luteal and follicular phases while the estrous cycle is 80% luteal and 20% follicular
- menstrual cycle involves endometrial shedding while the estrous cycle does not
what stages make up the follicular phase?
metestrus and estrus
what starts the follicular phase?
luteolysis (CL death)
what hormone must rapidly decline during proestrus? why?
progesterone so that GnRH is released at higher amplitudes and frequencies which eventually leads to the preovulatory surge of LH (decrease in P4 –> GnRH increases –> FSH and LH increase –> promotes follicular development –> production of E2 –> preovulatory surge of LH)
which hormone has positive feedback on GnRH where once it reaches a threshold concentration, results in the preovulatory surge of gonadotropins?
estrogen
when discussing follicular dynamics, what is atresia?
the process by which ovarian follicles that do not reach maturity degenerate and are reabsorbed by the ovary
which hormone stimulates recruitment and selection of follicles?
FSH
which hormone is the primary hormone responsible for ovulation?
LH
what is the basic description of the 2-cell 2-gonadotropin model? what are the 2 cells? 2 gonadotropins? what classification are the other two hormones involved?
- LH and FSH are released from the AP and travel through blood to the follicle
- theca cells have LH receptors (leads to production of testosterone)
- granulosa cells have FSH receptors (converts testosterone to estrogen using aromatase)
- steroid hormones (T and E2)
what is a basic definition of ovulation?
what changes occur in blood flow and blood vessels of ovary and follicle immediately prior to ovulation?
hyperemia (increased blood flow)
what secretions contribute to breaking down the CT to cause ovulation?
proteases (collagenase) and prostaglandins
which hormone causes contraction of the muscular components of the ovary to increase the pressure on the pre-ovulatory follicle?
oxytocin
what triggers the removal of meiotic inhibition in the female gamete?
the LH surge breaks down gap juntions
what are the three major processes of the luteal phase?
lutenization, hormone secretion, and regression of the CL
what is the dominant hormone of the luteal phase?
progesterone
what two major events mark the beginning and the end of the luteal phase?
what two stages of the estrous cycle occur during the luteal phase?
proestrus and diestrus
what is luteolysis? what hormone is responsible for this?
the process where luteal tissue (CL) undergoes regression and cell death; PGF2a and oxytocin are responsible for luteolysis
what is lutenization? what hormones cause this?
the process by which granulosa and theca cells are transformed into luteal cells; caused by LH
(transformation of the ruptured follicle into the corpus luteum after ovulation)
which cells develop into LLCs?
granulosa cells
which cells develop into SLCs?
theca cells
what hormone is secreted by the luteal cells of the CL?
progesterone
the hormone secreted by the CL has negative feedback on which structure/organ? this inhibits secretion of which hormone?
hypothalamus; GnRH –> AP; LH and FSH
where is PGF2a produced and secreted in female tract?
ovary (CL) and uterine endometrium
how is PGF2a transported to the ovary?
using vascular countercurrent exchange mechanism
why is a unique transport method necessary for PGF2a?
prostaglandins are metabolized at a high rate in the lungs (short half life in systemic circulation)
hoe does the internal environment of the female repro tract change with E2 vs P4?
- cervix: under E2, mucous is think and watery and cervix is tight and closed; under P4, mucous is tick and viscous and the cervix is soft and pliable
- uterus: E2 stimulates an increase in vascularity, thickening of the endometrium, myometrial contractions, uterine secretions, that capacitate sperm, and growth of endometrial glands; P4 causes endometrial glands to branch (increasing activity of endocrine glands), and stimulates “uterine milk” secretions (helps embryo continue development before placenta is established)
- oviduct: secretions are stimulated by estrogen which make the proper environment for the oocyte
- vagina: E2 promotes the maturation of the vaginal epithelium, leading to an increase in the thickness and glycogen content of vaginal cells
- clitoral fossa: excititory state under E2
how does the follicle produce E2?
- GnRH stimulates production of LH and FSH in the AP
- FSH binds to granulosa cells, producing testosterone
- LH binds to theca cells and aromatizes the testosterone into E2
- E2 is released into the bloodstream
how does the LH surge lead to ovulation?
- signal comes to follicle that causes the basement membrane to degenerate
- stimulates the resumption of meiosis resulting in 1st polar body and secondary oocyte
- causes the follicle to rupture: increased blood flow (increased pressure), stimulates production of collagenase which breaks down the follicular wall, causes release of oxytocin and prostaglandins that promote ovarian smooth muscle contraction
- follicle then ruptures
what are the four follicular dynamics of antral follicle growth?
- recruitment: FSH is increased prompting antral follicle growth
- selection: 1st to aquire LH receptors leading to increased dependency on LH, changes in hormone profile (E2 and P4)
- dominance: produce increasing E2 and inhibin, increase blood flow, granulosa cells aquire LH receptors (shifts from E2 production to P4 production right before ovulation)
- atresia
what are the five events of folliculogenesis?
- initiation and progression of pre-antral follicles
- recruitment of small antral follicles
- selection of growing cohort of recruited antral follicles
- dominance of one or more follicles
- follicular atresia ocurring continuously throughout folliculogenesis
