Clinical Physiology of Pregnancy

Question 1

pregnancy is a _______ specific event

Answer 1

species

Question 2

after the BOVINE embryo enters the uterus from the oviduct, what does it start doing

Answer 2

elongating

Question 3

what does the BOVINE embryo produce to signal maternal recognition of pregnancy

Answer 3

IFN-tau

Question 4

what horn does the bovine embryo enter and by what day

Answer 4

ipsilateral horn to CL, by day 24

Question 5

what is the purpose of embryo elongation in the COW

Answer 5

increases contact with the endometrium for secretion of IFN tau -> maternal recognition of pregnancy

Question 6

what is unique about HORSE embryo morphology

Answer 6

forms a capsule (day 7 - day 22) which is a glycoprotein layer surrounding the embryo that maintains a spherical shape

Question 7

the capsule in horses lies between which tissue layers

Answer 7

trophoblast and zona pellucida

Question 8

what is the mobility phase in equine embryo development

Answer 8

when the embryo whips around the uterus (both horns) up until day 16, where it fixates at the base of one horn

Question 9

T/F the horn where the horse embryo is undergoing the mobility phase (and whipping around) has decreased uterine contractions

Answer 9

F; increased at that spot

Question 10

what happens after embryo fixation (4)

Answer 10

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)

Question 11

what is the pregnancy hormone in every species except horses and why is it the pregnancy hormone (what does it do?)

Answer 11

progesterone; blocks myometrial contractions

Question 12

the ______ of progesterone varies by ___________ and _____________

Answer 12

source; species; stage of gestation

Question 13

REMINDER: go over the table for “gestational length and source of progesterone for maintenance of pregnancy”

Answer 13

I am done! (rank confidence as 5)

Question 14

describe the progesterone production by the CL and placenta during pregnancy in the cow

Answer 14

CL: peaks before 150d, drops, then peaks again around 260d

placenta: starts at 150d, then drops at 260d

Question 15

describe the following outcomes in pregnant cows:
- ovariectomy < 150d
- ovariectomy > 150d

Answer 15

1) abortion
2) abortion at approx 260d

Question 16

what happens to estrogen during pregnancy in ruminants (cows, sheep, goats)

Answer 16

peaks at the end of gestation

Question 17

describe the endocrinology of pregnancy in the MARE

Answer 17

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

Question 18

when do endometrial cups begin to form in the mare

Answer 18

day 35

Question 19

what are endometrial cups formed from? what do they produce?

Answer 19

fetal trophoblast cells that invade the maternal endometrium; PSMG aka eCG

Question 20

when is eCG detectable

Answer 20

days 35-120

Question 21

what does eCG do in horses? what about ruminants?

Answer 21

acts like LH in the horse -> secondary CL formation -> progesterone

acts like FSH in the ruminant -> used for breeding synchronization programs

Question 22

what happens if the equine fetus dies while endometrial cups are still present

Answer 22

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

Question 23

T/F the mare will not come back into heat until endometrial cups regress (assuming foal dies)

Answer 23

T

Question 24

what is involved in destruction of the endometrial cups

Answer 24

T lymphocytes (from the mare)

Question 25

during equine pregnancy there is a rise in estrogen and progestagens; where does the estrogen and progestagens come from?

Answer 25

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

Question 26

placental progestagens start being produced by day _____ and are the primary source of pregnancy hormones by day ___

Answer 26

70; 120 (note, this is also when the endometrial cups have regressed)

Question 27

from day ______ through ______, the fetal gonads are larger than the mares gonads

Answer 27

150; 220

Question 28

how exactly do equine gonads produce estrogen? what are examples of the estrogens produced that are specific to the horse

Answer 28

they produce DHEA, which is converted by the placenta to various estrogens ; estrogens specific to the horse are equilin and equilelin

Question 29

what are equilin and equilelin

Answer 29

estrogens produced by the foal gonads and converted by the placenta

Question 30

what is the role of the estrogens produced by the foal gonads during equine pregnancy (3)

Answer 30

• normal fetal growth
• normal myometrial contractions during labour
• normal mammary gland development

Question 31

T/F foal estrogens are essential for maintenance of the pregnancy

Answer 31

F

Question 32

what does the fetal adrenal gland produce during gestation

Answer 32

progestagens such as 5 α DHP (5α pregnanes) and pregnenolone

Question 33

what is responsible for the progesterone block in mare pregnancy

Answer 33

5 α pregnanes and pregnenolone produced by the fetal adrenal gland