Ex 3 - Physiology of Pregnancy Flashcards
What is embryonic loss? and what is the incidence?
pregnancy loss prior to fetal stage; 2-20%
*conception rates are often very high, but uterine pregnancy rates are much lower –> this suggests that early embryonic loss rates are significant
What happens if embryo is lost prior to MRP?
CL regresses at normal time; no delay in return to estrus –> continues to cycle
What happens if embryo is lost after MRP?
CL persists (2-3 months); delay in return to estrus –> loss of breeding season for that animal
*can give PGF to cause luteolysis to cause animal to cycle back
When do pig embryos enter the uterus?
at ~48 hrs
MRP in pigs
embryos migrate throughout uterus beginning on day 8-9 and spread apart –> cross-horn migration occurs –> migration stops at day 12
How many embryos are req’d for MRP to occur in PIGS?
at least 4 and at least 1 embryo must be in each uterine horn
What are some causes of early pregnancy loss?
maternal age, endometrial/uterine dz, P4 insufficiency, chromosomal abnormalities
others: nutrition, stress, early postpartum pregnancies
What is the placental membrane composed of?
maternal and embryonic/fetal components
What is the fetal membrane composed of?
only the fetal component
How does embryo get nutrients in early pregnancy?
secretions from endometrial glands –> micronutrients –> taken up by trophoblast cells, and eventually by the vascularized yolk sac
“Histotrophic support”
How does embryo get nutrients in later pregnancy?
Development of close assoc’d b/w maternal and fetal membranes
“Hemotrophic support”
What is implantation/attachment? and when does it occur?
- pigs
- sheep
- cows
- horses
An interdigitation of placental tissue with endometrium
- 14-18 days
- 15-18 days
- 18-22 days
- 35-38 days
what is the amnion and when does it develop?
membrane directly around fetus; 21 days
What is chorioallantois?
outer placental membrane
what is blastocoele cavity?
yolk sac –> storage of nutrients for embryonic development
