Embryo development

Question 1

xMitotic divisions with no increase in cell mass

Answer 1

cleavage

Question 2

Capable of producing a complete individual

Answer 2

totipotency

Question 3

Compact ball of cells of approximately equal size

Answer 3

morula

Question 4

Cells have rearranged to have compartments

Answer 4

blastocyst

Question 5

Gives rise to the embryo

Answer 5

inner cell mass

Question 6

Gives rise to the placenta

Answer 6

trophectoderm

Question 7

The fluid-filled cavity of a blastocyst

Answer 7

blastocoele

Question 8

What does it mean for a blastocyst to hatch?

Answer 8

The zona pellucida is removed via enzymes produced by the trophoblasts, allowing for the expansion and attachment of the blastocyst

Question 9

Fertilization of 2 ova resulting in non-identical twins

Answer 9

Dizygotic

Question 10

Splitting of 1 ovum resulting in genetically identical twins

Answer 10

Monozygotic

Question 11

When a blastocyst rearranges to form the endoderm, mesoderm, and ectoderm

Answer 11

Gastrulation

Question 12

innermost pocket where fetus develops

Answer 12

Amnion

Question 13

Combination of trophectoderm and mesoderm; becomes the outermost layer of the placenta and attaches to the metrium

Answer 13

Chorion

Question 14

Direct communication to maternal blood

Answer 14

allantochorion

Question 15

Waste receptacle

Answer 15

allantois

Question 16

The process by which the conceptus signals its presence to the mother

Answer 16

maternal recognition of pregnancy (MRP)

Question 17

MRP occurs between day __________ of the estrus cycle, before luteolysis

Answer 17

14-16

Question 18

2 methods of MRP

Answer 18

antiluteolytic and luteotropic

Question 19

MRP signal originates from the…

Answer 19

trophectoderm

Question 20

prevents or blocks luteolysis
ie blocks PGF release- estrone sulfate

Answer 20

antiluteolytic

Question 21

stimulates CL to continue function even in the face of PGF (ex. PGE and HCG)

Answer 21

luteotropic

Question 22

MRP signal acts directly on the…

Answer 22

endometrium and/or the ovary

Question 23

In ruminants, the MRP interferon tau acts as..

Answer 23

anti-luteolytic

Question 24

What are the Sows’ MRP? (2)

Answer 24

-E2 produced by the trophectoderm
-shift PGF to PGE and increase blood flow
(Both anti-luteolytic and luteotropic)

Question 25

What is the mare's MRP?

Answer 25

Unknown; thought to be movement of embryo since knocking out interferon tau doesn't affect anything

Question 26

In humans, HCG is ________ since it acts like LH

Answer 26

luteotropic

Question 27

How does an open/non-pregnant animal know they're not pregnant?

Answer 27

Between days 14-16 of estrus, oxytocin increases and binds to receptors, causing smooth muscle contractions, and increasing PGF2a which kills CL's present and decreases P4

Question 28

Generally, how does MRP work in a pregnant animal?

Answer 28

Between days 14-16, oxytocin is unable to bind its receptors due to the specific MRP signal (species variations), so SM contractions decrease, PGF2a decreases so the CL continues to live, increase P4 and maintain a pregnancy

Question 29

How does MRP work in a pregnant sow?

Answer 29

-at least 3 piglets = needed to produce enough E2 (MRP) -E2 = a vasodilator, and changes the direction of blood flow which diverts PGF2a to the uterus where it degrades instead of reaching any CLs present on the ovaries

Question 30

Initial sticky attachment between the placenta and embryo

Answer 30

immobilization

Question 31

Intimate contact of the developing embryo with the uterine mucosa

Answer 31

implantation

Question 32

The embryo sits on top of the endometrium -ex. ruminants, equine, sows

Answer 32

Non-invasive type placenta

Question 33

Trophoblast cells produce enzymes that allow the embryo to burrow into the endometrium -ex. primates, rodents, cats, dogs

Answer 33

Invasive type placenta

Question 34

The blastocoele of the blastocyst becomes the _____ of the developing embryo

Answer 34

yolk sac

Question 35

protein hormone of pregnancy in ruminants and humans that acts like growth hormone

Answer 35

placental lactogen

Question 36

Prior to what day of gestation is a ewe's pregnancy dependent on the presence of the corpus luteum?

Answer 36

Day 40

Question 37

Which of the following hormones is absolutely required for pregnancy to ensue in the mare? a.Progesterone b.Estrogen c.Pregnant mare serum gonadotropin d.Equine Chorionic gonadotropin e.Placental lactogen

Answer 37

a. Progesterone