Maternal Recognition of Pregnancy Flashcards
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continuation of cyclicity occurs due to
luteolysis
the maternal recognition of pregnancy is defined as
Series of events where conceptus
signals its presence
Prevents luteolysis (saves corpus luteum) so progesterone can establish
pregnancy
pregancy recognition factors in rodents
prolactin
pregnancy recognition factors in ruminants
interferon τ, aka (IFN τ)
pregnancy recognition factors in pigs
estrogen
in bitch and queen
no anti-luteolytic signal (or pregnancy signal)
IFNT -τ
Anti-luteolytic hormone for pregnancy recognition and CL maintenance, silences expression of
estrogen receptors which:
blocks OXT-induced release of
luteolytic pulses of PGF2α,
preventing CL regression
Name the stages of transuterine migration of the equine conceptus
1) Embryo mobility
2) Inhibition of luteolysis
3) Embryo fixation
4) Orientation
embryo mobility in equines is facilitated by
prostaglandins inducing uterine contractions either at the conceptus or origin of uterus
Function of the Equine Embryonic Capsule
becomes the outermost layer after the shedding of the zona pellucida to become a supportive wrapping of the embryo while it experiences mobility, fixation and orientation
Maternal Recognition of Pregnancy in Pigs
Estrogen produces anti-luteolytic effect that directs PGF2a into the uterine lumen where it is metabolized
prolactin and Ca2+ also involved
define embryo implantation
Process by which the embryo attaches to the endometrium of the uterus
types of implantation are classified by
the extent of blastocyst penetration into the uterine wall at the invasion stage
Non-invasive implantation
- superficial
- blastocyst expands to fill the lumen of the uterus/uterine horn
- blastocyst doesn’t erode, instead grows large enough to fully contact the surface of the lumen in order to fuse to it without penetration
non-invasive implantation occurs in what species?
horses, cattle, sheep, pigs, dogs, cats
types of invasive implantation
interstitial vs. eccentric
Interstitial implantation
the blastocyst remains small and fully embeds into the uterine wall (primates)
Eccentric Implantation
the bastocyst remains small and **only partially **embeds into the uterine wall (rodents)
name the phases of embryo implantation
- apposition
- attachment/adhesion
- invasion
what occurs during apposition?
the hatched blastocyst establishes it’s contact with the endometrium
what occurs during attachment/adhesion?
the association between the trophoblast and epithelium strengthens through the interaction of adhesion molecules
What occurs during invasion?
human trophoblast invades tissue and secures blood supply
non-invasive embryo implantation occurs in
domestic animals
(apposition to adhesion)
invasive embryo implantation occurs in
primates
apposition –> adhesion –> invasion