MRP And Placentation

Question 1

What 3 things happen before embryo attaches to uterus?

Answer 1

1. Develops within zona pellucida to blastocyst
2. Hatch from ZP
3. Undergo maternal recognition of pregnancy (MRP)

Question 2

What constitutes maternal recognition of pregnancy?

Answer 2

Preservation of corpus luteum
Occurs before luteolysis
Increased progesterone

Question 3

Explain how MRP occurs in ruminants

Answer 3

Interferon tau (INF-T) from trophoblasts inhibits oxytocin receptor synthesis which then inhibits PGF2a release

Question 4

Explain how MRP occurs in sows

Answer 4

Blastocyst makes estrogen which reroutes PGF2a release into uterine lumen which then destroys the PGF2a

Question 5

Explain how MRP occurs in mares

Answer 5

Blastocyst migration throughout uterine lumen and decreased synthesis of PGF2a

Question 6

Explain MRP in dogs and cats

Answer 6

Doesn’t require signal because CL lifespan is similar with and without pregnancy

Question 7

What is the difference between the ruminant blastocyst and the mare blastocyst?

Answer 7

Ruminant blastocyst is filamentous and you can’t see it until 30 days

Mare blastocyst is spherical and you can see it in 14 days

Question 8

What is the origin of the placenta?

Answer 8

Chorioallantois

Question 9

What are the functions of the placenta?

Answer 9

Metabolic interchange
Increased progesterone maintains pregnancy
Relaxin induces parturition
Equine chorionic gonadotropin (ECG) stimulates ovarian function
Lactogen in ewes stimulates mammary function

Question 10

What kind of placenta do horses, pigs, and camelids have?

Answer 10

Diffuse, epitheliochorial

Question 11

What kind of placenta do ruminants have?

Answer 11

Cotyledonary, epitheliochorial

Question 12

What kind of placenta do dogs and cats have?

Answer 12

Zonary, endotheliochorial
(Also seals, bears, and elephants)

Question 13

What kind of placenta do primates and rodents have?

Answer 13

Discoid, hemochorial