Exam 3 - Fertilization, Pregnancy, Placenta, Parturition

Question 1

what is the cortical reaction

Answer 1

release of phospholipase Czeta = Calcium Spike = alter zona pellucida and prevent other sperm from penetrating “zona hardening”

Question 2

what is the site of fertilization?

Answer 2

ampulla

Question 3

what blocks polyspermy

Answer 3

zona hardening

Question 4

what does the trophoblast form?

Answer 4

placenta

Question 5

what does the inner cell mass form?

Answer 5

fetus

Question 6

how does cow and equine embryo development differ

Answer 6

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

Question 7

what hormone is required by all females to maintain pregnancy

Answer 7

progesterone

Question 8

maternal recognition of pregnancy in bovine & ovine?

Answer 8

IFN-𝜏 which inhibits oxytocin receptors and cannot stimulate PGF2𝛼

elongate on ipsilateral side

Question 9

maternal recognition of pregnancy in pigs?

Answer 9

estradiol (E2) - total of 4 embryos required for MRP

cross-horn migration (litter bearing)

Question 10

maternal recognition of pregnancy in horses?

Answer 10

unknown - embryo spherical and migrate throughout the uterine lumen = facilitate signaling the entire endometrium

Important relative to systemic circulation of PGF2𝛼

Question 11

what are the CL dependent species for progesterone throughout pregnancy

Answer 11

dogs
cats
goats
pigs
camelids

Question 12

what species depend on the CL then the placenta for progesterone throughout pregnancy

Answer 12

horses
cow
sheep

Question 13

when do horses form endometrial cups and what is their significance

Answer 13

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

Question 14

what occurs if a pregnancy loss occurs after day 35 in the mare?

Answer 14

cups remain present, eCG continued to be produced and mare is “lost for the season”

Question 15

why might a pregnant mare have aggressive/stallion like behavior?

Answer 15

fetal gonads undergo enlargement = androgens & estrogen production which may increase in maternal blood

Question 16

what is the most common procedure done when a mare has twins

Answer 16

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

Question 17

what species have a diffuse placenta

Answer 17

horses
pigs

Question 18

what species have a cotyledonary placenta

Answer 18

ruminants

Question 19

what species have a zonary placenta

Answer 19

carnivores (dogs/cat)

Question 20

what species have a discoid placenta

Answer 20

primates

Question 21

Epitheliochorial
species?
layers?
Ig transfer?

Answer 21

large animals
6 layers
no placental Ig transfer - colostrum is critical for survival

Question 22

Endotheliochorial
species?
layers?
Ig transfer?

Answer 22

carnivores (dogs/cats)
4 layers
some placenta Ig transfer

Question 23

Hemochorial
species?
layers?
Ig transfer?

Answer 23

primates/rodents
3 layers
significant Ig placental transfer

Question 24

what are the 4 positive signs of pregnancy in cattle

Answer 24

1. Palpation of amniotic vesicle
2. Fetal membrane slip
3. Palpation of placentome
4. Palpation of fetus

Question 25

what is a suggestive sign of pregnancy in cattle but not positive

Answer 25

Fremitus in middle uterine a. (fluid movement with a buzz)

Question 26

what are 2 positive signs of pregnancy in the horse

Answer 26

1. fetal bulge
2. fetal movement

will NOT have a membrane slip or placentomes because they have a diffuse placenta!

Question 27

US techniques in small animals for pregnancy detecton? large animals?

Answer 27

transabdominal in SA
transrectal in LA

Question 28

what is a diagnostic test to accurately count the number of fetuses?

Answer 28

radiographs

Question 29

endocrine testing in the dog for pregnancy detection

Answer 29

NOT progesterone (similar during pregnancy & non-preg)
Relaxin - day 30
Acute Phase Proteins

Question 30

endocrine testing in the cow for pregnancy detection

Answer 30

absence of Progesterone
estrone sulfate
IFN-𝜏
EPF

Question 31

endocrine testing in the horse for pregnancy detection

Answer 31

absence of Progesterone
EPF
eCG
estrone sulfate
relaxin

Question 32

a dog is bleeding at the margins of the placenta and it has greenish color, normal or abnormal?

Answer 32

marginal hematoma
normal

Question 33

function of microcotyledons in the mare

Answer 33

attach the chorioallantois
NOT present at the cervical star

Question 34

what determines the “readiness for birth” or time for parturition

Answer 34

the fetus - cortisol causes increased E, decreased P (increased E:P ratio)

allows relaxin, oxytocin and prostaglandins to be increased

Question 35

what is the ferguson reflex

Answer 35

fetus stimulates cervix = oxytocin release = oxytocin enhances prostaglandins for uterine contraction

Question 36

in litter bearing species, parturition is initiated by signals from the entire litter, true or false

Answer 36

true

Question 37

what are the stages of labor

Answer 37

stage 1 - initiation of myometrial contractions
stage 2 - delivery of fetus
stage 3 - delivery of fetal membranes

Question 38

how to induce labor in ruminants?

Answer 38

corticosteroids

Question 39

how to induce labor in CL dependent species?

Answer 39

prostaglandins

Question 40

how to induce labor in horses?

Answer 40

oxytocin

Question 41

end of stage I of parturition in LA? SA?

Answer 41

LA - rupture of chorionallantois
SA - full dilation of cervix