3. Reproductive physiology of the pig Flashcards
Role of pigs
- pork
- biological model for human research (anatomy, physiology)
- European standards for minipig research
- production of active substances, organs
- surgical model
Porcine genital tract
Major functions of the ovary
- Cyclic production of fertilisable ova
- Production of balanced ratio of steroid hormones
- development of the genital tract
- migration of the early embryo
- implantation
The follicle fulfills the dual function of gametogenesis and steroidogenesis
Ovarian features during estrous cycle
Life cycle of the porcine ovary
-> primordial follicle -> primary follicle -> secondary follicle -> early antral follicle -> atretic follicle -> Graafian follicle -> ovulation -> early corpus luteum -> mature corpus luteum -> corpus albicans -> repeat
Primordial follicle
- follicle with central located oocysts and single layer of granulosa cells
- oocyte in an arrested meiotic prophase
- gonadotropin independent growth
Primary follicle
- follicle growth, proliferation of granulosa cells, zona pellucida formation (role: protection of oocyte), then a cell differentiation
- fully grown oocyte
- gonadotropin dependent growth
Secondary follicle
- follicle growth, increased number of granulosa cell layers
- fully grown oocyte
- gonadotropin dependent growth
Early tertiary (antral) follicle
- formation of antrum, increased number of granulosa cell layers
- fully grown oocyte
- gonadotropin dependent growth
- secretion of steroids by granulosa and the a cells
Pre-ovulatory follicle
- secretion of androstendion by theca cells and estradiol by granulosa cells.
- oocyte at Metaphase II stage.
- large amount of FF with high concentrations of estradiol in follicular phase and progesterone at ovulation
Peri-ovulatory/ luteinizing follicle
- follicle rupture, discharge of a mature, fertilisable ovum
- development of lutein cells
- synthesis and secretion of progesterone
- formation of luteum tissue starts couple of hours before ovulation
Ovulation. Follicle rupture
“Flow out” of a mature follicle and discharge of a n oocyte (cumulus-oocyte-complex) into the oviduct
Cumulus-oocyte-complex
Ovulation - an inflammatory-like process?
Formation of a pig corpus luteum
Corpus luteum cell types
Luteolysis — ?
The process whereby the corpus luteum degenerates near the end of the nonfertil estrous cycle
Mechanisms regulating the lifespan of corpora lutea
- reduction of LH pulse amplitude
- increase in estrogen secretion
- influence of PGF2-alpha
Ovarian development and hormone. Secretion during the estrous cycle
Dynamic of follicular growth. Recruitment? Selection?
Recruitment — the process wherein the follicle departs from the resting pool to begin a pattern of growth and development. Though recruitment is obligatory, it does not guarantee ovulation
Selection — the final winnowing of maturing follicular cohort by atresia down to a size equal to the special-characteristic ovulatory y quota
????
1 vs 2 waves of follicular development
Recruitment and selection of follicles during the oestrus cycle
Dual function of the follicle
Follicular fluid
Follicular fluid
Intrafollicular oocyte development
