Early Embryogenesis 2 (Ch. 13)

Question 1

Gametes develop in the ___

Answer 1

Yolk sac

Question 2

Two sacks will form in the embryo, what are they called and what are their functions?

Answer 2

Amnion: allows for fetal symmetry
Allantois: recycles nutrients for fetal growth

Question 3

What hormone initiates secretions that are necessary for pregnancy?

Answer 3

Progesterone (P4)

Question 4

All livestock, except ___, will encounter the elongation process

Answer 4

Horses

Question 5

What significant event happens during the elongation process of the embryo in ruminants?

Answer 5

Interferon tau is produced, which informs the mother of pregnancy

Question 6

Prostaglandin is pulsed in the presence of ___ (hormone)

Answer 6

Oxytocin

Question 7

(T/F) Oxytocin is still released during pregnancy

Answer 7

True!

Question 8

During pregnancy the oxytocin receptors are blocked by ___ in what species?

Answer 8

Interferon tau (INF-t)
Ewe and cow

Question 9

What kind of cells produce IFN-t?

Answer 9

Mononuclear cells

Question 10

(T/F) All animals produce INF-t

Answer 10

False!

Only ruminants produce this

Question 11

Maternal recognition of pregnancy must occur prior to ___

Answer 11

Luteolysis

Question 12

Describe how INF-t works

Answer 12

It is secreted by the trophoblast cells and decreases endometrial oxytocin receptors
This prevents PGF2-alpha synthesis and stops luteolysis

Question 13

What is the conceptus?

Answer 13

It is the embryo and its adjunct parts

Question 14

What happens in the sow that prevents luteolysis?

Answer 14

Estradiol reroutes PGF2-alpha

Question 15

When a sow is pregnant the PGF2-alpha will be secreted (endocrine/exocrine)

Answer 15

Exocrine

Question 16

(T/F) The faster an embryo elongates, the more nutrients it will be exposed to

Answer 16

True!

Question 17

When is STAT-1 released?

Answer 17

When a placenta is present

Question 18

(T/F) If an oocyte is not fertilized in a mare it will migrate out of the oviduct

Answer 18

False!

It will stay in the oviduct

Question 19

Briefly describe what each one does:

1. yolk sac
2. chorion
3. amnion
4. allantois

Answer 19

1. provides nutrients
2. will attach to placenta
3. provides a protective sac for fetus
4. collects liquid waste from embryo