Maternal Recognition of Pregnancy

Question 1

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continuation of cyclicity occurs due to

Answer 1

luteolysis

Question 2

the maternal recognition of pregnancy is defined as

Answer 2

Series of events where conceptus
signals its presence

Prevents luteolysis (saves corpus luteum) so progesterone can establish
pregnancy

Question 3

pregancy recognition factors in rodents

Answer 3

prolactin

Question 4

pregnancy recognition factors in ruminants

Answer 4

interferon τ, aka (IFN τ)

Question 5

pregnancy recognition factors in pigs

Answer 5

estrogen

Question 6

in bitch and queen

Answer 6

no anti-luteolytic signal (or pregnancy signal)

Question 7

IFNT -τ

Answer 7

Anti-luteolytic hormone for pregnancy recognition and CL maintenance, silences expression of
estrogen receptors which:

blocks OXT-induced release of
luteolytic pulses of PGF2α,
preventing CL regression

Question 8

Name the stages of transuterine migration of the equine conceptus

Answer 8

1) Embryo mobility
2) Inhibition of luteolysis
3) Embryo fixation
4) Orientation

Question 9

embryo mobility in equines is facilitated by

Answer 9

prostaglandins inducing uterine contractions either at the conceptus or origin of uterus

Question 10

Function of the Equine Embryonic Capsule

Answer 10

becomes the outermost layer after the shedding of the zona pellucida to become a supportive wrapping of the embryo while it experiences mobility, fixation and orientation

Question 11

Maternal Recognition of Pregnancy in Pigs

Answer 11

Estrogen produces anti-luteolytic effect that directs PGF2a into the uterine lumen where it is metabolized

prolactin and Ca2+ also involved

Question 12

define embryo implantation

Answer 12

Process by which the embryo attaches to the endometrium of the uterus

Question 13

types of implantation are classified by

Answer 13

the extent of blastocyst penetration into the uterine wall at the invasion stage

Question 14

Non-invasive implantation

Answer 14

• superficial
• blastocyst expands to fill the lumen of the uterus/uterine horn
• blastocyst doesn’t erode, instead grows large enough to fully contact the surface of the lumen in order to fuse to it without penetration

Question 15

non-invasive implantation occurs in what species?

Answer 15

horses, cattle, sheep, pigs, dogs, cats

Question 16

types of invasive implantation

Answer 16

interstitial vs. eccentric

Question 17

Interstitial implantation

Answer 17

the blastocyst remains small and fully embeds into the uterine wall (primates)

Question 18

Eccentric Implantation

Answer 18

the bastocyst remains small and **only partially **embeds into the uterine wall (rodents)

Question 19

name the phases of embryo implantation

Answer 19

• apposition
• attachment/adhesion
• invasion

Question 20

what occurs during apposition?

Answer 20

the hatched blastocyst establishes it’s contact with the endometrium

Question 21

what occurs during attachment/adhesion?

Answer 21

the association between the trophoblast and epithelium strengthens through the interaction of adhesion molecules

Question 22

What occurs during invasion?

Answer 22

human trophoblast invades tissue and secures blood supply

Question 23

non-invasive embryo implantation occurs in

Answer 23

domestic animals
(apposition to adhesion)

Question 24

invasive embryo implantation occurs in

Answer 24

primates

apposition –> adhesion –> invasion

Question 25

steps of non-invasive implantation

Answer 25

Implantation of blastocysts for ruminants and pigs includes:
1) Hatching from zona pellucida
2) Precontact and orientation of the blastocyst with uterine luminal epithelium (LE)
3) Apposition between conceptus trophectoderm and uterine LE
4) Adhesion of conceptus trophectoderm to uterine LE
5) No endometrial invasion by the conceptus

Question 26

steps of invasive implantation

Answer 26

Zona Hatching: early bastocyst hatches from zona pellucida
Apposition: blastocyst establishes contact with endometrium
Adhesion/Attachment: increased communication between embryo and endometrium (autocrine/paracrine secretion)
**Invasion: **blastocyst invades and buries into uterine to reach blood supply

Question 27

Syncytiotrophoblast

Answer 27

• the outer layer that covers the interface between the embryo and the maternal blood vessels
• produces human chorionic gonadotropin (hCG) which rescues the corpus luteum

Question 28

Cytotrophoblast

Answer 28

a single sheet of cells surrounding the extraembryonic mesoderm

Question 29

Gastrulation

Answer 29

Formation of germ layers – ectoderm, mesoderm, and endoderm

Question 30

embryonic folding

Answer 30

• folding of flat trilaminar disc into cylindrical embryo
• occurs in median and horizontal planes, due to rapid embryo growth
• Endodermal, mesodermal, and ectodermal layers of the embryonic disc fuse to the corresponding layer on the opposite side, creating a 3-D tubular form
• Separates embryo from its extraembryonic membranes

Question 31

organogenesis

Answer 31

The formation of organ rudiments and organ systems

Question 32

Steps of Embryo and Fetal Development

Answer 32

1) Gastrulation
2) Formation of tube-within-a-tube body plan (germ layers)
3) organogenesis

Question 33

formation of germ layers

Answer 33

Bilaminar disc – Epiblast and Hypoblast; Trilaminar disc – Endoderm, Mesoderm and Ectoderm

Question 34

germ layer derivates

Answer 34

Endoderm: digestive system, lungs, endocrine
Mesoderm: muscle, skeleton, cardiovascular, reproductive
Ectoderm: nervous system, skin, hair

Question 35

define embryo

Answer 35

organism in early stages of development

Question 36

conceptus

Answer 36

product of conception

Question 37

conceptus includes

Answer 37

• embryo during early embryonic stage
• embryo and extraembryonic membranes during preimplantation stage
• fetucs and placenta during post-attachment phase