Clinical Physiology of Pregnancy Flashcards
pregnancy is a _______ specific event
species
after the BOVINE embryo enters the uterus from the oviduct, what does it start doing
elongating
what does the BOVINE embryo produce to signal maternal recognition of pregnancy
IFN-tau
what horn does the bovine embryo enter and by what day
ipsilateral horn to CL, by day 24
what is the purpose of embryo elongation in the COW
increases contact with the endometrium for secretion of IFN tau -> maternal recognition of pregnancy
what is unique about HORSE embryo morphology
forms a capsule (day 7 - day 22) which is a glycoprotein layer surrounding the embryo that maintains a spherical shape
the capsule in horses lies between which tissue layers
trophoblast and zona pellucida
what is the mobility phase in equine embryo development
when the embryo whips around the uterus (both horns) up until day 16, where it fixates at the base of one horn
T/F the horn where the horse embryo is undergoing the mobility phase (and whipping around) has decreased uterine contractions
F; increased at that spot
what happens after embryo fixation (4)
1) increased uterine tone
2) rapid growth in diameter of the embryo
3) capsule becomes sticky and adherent to the endometrium
4) embryo orients so that the embryo proper is at the base of the vesicle (in contact with endometrium)
what is the pregnancy hormone in every species except horses and why is it the pregnancy hormone (what does it do?)
progesterone; blocks myometrial contractions
the ______ of progesterone varies by ___________ and _____________
source; species; stage of gestation
REMINDER: go over the table for “gestational length and source of progesterone for maintenance of pregnancy”
I am done! (rank confidence as 5)
describe the progesterone production by the CL and placenta during pregnancy in the cow
CL: peaks before 150d, drops, then peaks again around 260d
placenta: starts at 150d, then drops at 260d
describe the following outcomes in pregnant cows:
- ovariectomy < 150d
- ovariectomy > 150d
1) abortion
2) abortion at approx 260d
what happens to estrogen during pregnancy in ruminants (cows, sheep, goats)
peaks at the end of gestation
describe the endocrinology of pregnancy in the MARE
1) primary CL
2) formation of endometrial cups -> secretion of PSMG
3) formation of secondary CL
4) high levels of estrogen
5) low levels of progesterone after 150d until close to term
when do endometrial cups begin to form in the mare
day 35
what are endometrial cups formed from? what do they produce?
fetal trophoblast cells that invade the maternal endometrium; PSMG aka eCG
when is eCG detectable
days 35-120
what does eCG do in horses? what about ruminants?
acts like LH in the horse -> secondary CL formation -> progesterone
acts like FSH in the ruminant -> used for breeding synchronization programs
what happens if the equine fetus dies while endometrial cups are still present
they will continue to produce eCG (they have a preprogrammed lifespan) and the mare will continue to think she is pregnant until they regress at 120d
T/F the mare will not come back into heat until endometrial cups regress (assuming foal dies)
T
what is involved in destruction of the endometrial cups
T lymphocytes (from the mare)
during equine pregnancy there is a rise in estrogen and progestagens; where does the estrogen and progestagens come from?
estrogens: from the fetal gonads (they dramatically increase in size during this point) starting on day 70
progestagens: from the placenta starting on day 70
placental progestagens start being produced by day _____ and are the primary source of pregnancy hormones by day ___
70; 120 (note, this is also when the endometrial cups have regressed)
from day ______ through ______, the fetal gonads are larger than the mares gonads
150; 220
how exactly do equine gonads produce estrogen? what are examples of the estrogens produced that are specific to the horse
they produce DHEA, which is converted by the placenta to various estrogens ; estrogens specific to the horse are equilin and equilelin
what are equilin and equilelin
estrogens produced by the foal gonads and converted by the placenta
what is the role of the estrogens produced by the foal gonads during equine pregnancy (3)
- normal fetal growth
- normal myometrial contractions during labour
- normal mammary gland development
T/F foal estrogens are essential for maintenance of the pregnancy
F
what does the fetal adrenal gland produce during gestation
progestagens such as 5 α DHP (5α pregnanes) and pregnenolone
what is responsible for the progesterone block in mare pregnancy
5 α pregnanes and pregnenolone produced by the fetal adrenal gland
