Exam 3 - Fertilization, Pregnancy, Placenta, Parturition Flashcards
what is the cortical reaction
release of phospholipase Czeta = Calcium Spike = alter zona pellucida and prevent other sperm from penetrating “zona hardening”
what is the site of fertilization?
ampulla
what blocks polyspermy
zona hardening
what does the trophoblast form?
placenta
what does the inner cell mass form?
fetus
how does cow and equine embryo development differ
cow
- all fertilized or unfertilized embryos travel to the uterus
- “hatching” & embryo can be in any configuration “elongated” to fill uterine horn
horse
- only fertilized embryos travel to uterus - must produce PGE2 to travel
- ZP is thinned & shed
- only species to have a capsule which keeps embyro in “spherical” configuration
what hormone is required by all females to maintain pregnancy
progesterone
maternal recognition of pregnancy in bovine & ovine?
IFN-𝜏 which inhibits oxytocin receptors and cannot stimulate PGF2𝛼
elongate on ipsilateral side
maternal recognition of pregnancy in pigs?
estradiol (E2) - total of 4 embryos required for MRP
cross-horn migration (litter bearing)
maternal recognition of pregnancy in horses?
unknown - embryo spherical and migrate throughout the uterine lumen = facilitate signaling the entire endometrium
Important relative to systemic circulation of PGF2𝛼
what are the CL dependent species for progesterone throughout pregnancy
dogs
cats
goats
pigs
camelids
what species depend on the CL then the placenta for progesterone throughout pregnancy
horses
cow
sheep
when do horses form endometrial cups and what is their significance
35 days of pregnancy
produce eCG which allows ovulation/lutenization of large follicles and secondary/accessory CL to form = more progesterone, extra support for pregnancy
what occurs if a pregnancy loss occurs after day 35 in the mare?
cups remain present, eCG continued to be produced and mare is “lost for the season”
why might a pregnant mare have aggressive/stallion like behavior?
fetal gonads undergo enlargement = androgens & estrogen production which may increase in maternal blood
what is the most common procedure done when a mare has twins
most likely will abort thus you do a pregnancy reduction on day 14-16 and remove one fetus so the other can be carried to term
what species have a diffuse placenta
horses
pigs
what species have a cotyledonary placenta
ruminants
what species have a zonary placenta
carnivores (dogs/cat)
what species have a discoid placenta
primates
Epitheliochorial
species?
layers?
Ig transfer?
large animals
6 layers
no placental Ig transfer - colostrum is critical for survival
Endotheliochorial
species?
layers?
Ig transfer?
carnivores (dogs/cats)
4 layers
some placenta Ig transfer
Hemochorial
species?
layers?
Ig transfer?
primates/rodents
3 layers
significant Ig placental transfer
what are the 4 positive signs of pregnancy in cattle
- Palpation of amniotic vesicle
- Fetal membrane slip
- Palpation of placentome
- Palpation of fetus
what is a suggestive sign of pregnancy in cattle but not positive
Fremitus in middle uterine a. (fluid movement with a buzz)
what are 2 positive signs of pregnancy in the horse
- fetal bulge
- fetal movement
will NOT have a membrane slip or placentomes because they have a diffuse placenta!
US techniques in small animals for pregnancy detecton? large animals?
transabdominal in SA
transrectal in LA
what is a diagnostic test to accurately count the number of fetuses?
radiographs
endocrine testing in the dog for pregnancy detection
NOT progesterone (similar during pregnancy & non-preg)
Relaxin - day 30
Acute Phase Proteins
endocrine testing in the cow for pregnancy detection
absence of Progesterone
estrone sulfate
IFN-𝜏
EPF
endocrine testing in the horse for pregnancy detection
absence of Progesterone
EPF
eCG
estrone sulfate
relaxin
a dog is bleeding at the margins of the placenta and it has greenish color, normal or abnormal?
marginal hematoma
normal
function of microcotyledons in the mare
attach the chorioallantois
NOT present at the cervical star
what determines the “readiness for birth” or time for parturition
the fetus - cortisol causes increased E, decreased P (increased E:P ratio)
allows relaxin, oxytocin and prostaglandins to be increased
what is the ferguson reflex
fetus stimulates cervix = oxytocin release = oxytocin enhances prostaglandins for uterine contraction
in litter bearing species, parturition is initiated by signals from the entire litter, true or false
true
what are the stages of labor
stage 1 - initiation of myometrial contractions
stage 2 - delivery of fetus
stage 3 - delivery of fetal membranes
how to induce labor in ruminants?
corticosteroids
how to induce labor in CL dependent species?
prostaglandins
how to induce labor in horses?
oxytocin
end of stage I of parturition in LA? SA?
LA - rupture of chorionallantois
SA - full dilation of cervix
