Fertilization

Question 1

Most mammals are born with oogenesis arrested at the ____ ______ stage.

Answer 1

Primary oocyte

*prophase of meiosis 1

Question 2

Rabbits, ferrets, and hamsters are born with oogenesis arrested at the less developed, ______ stage.

Answer 2

Oogonia

Question 3

Meiosis is resumed at the time of _____, with an ovulatory surge of ___.

Answer 3

puberty, LH

Question 4

Stage at which oocyte growth is complete

Answer 4

Antrum formation

Question 5

The ovulation stage for most mammals is when the oocyte enters the ______ _____ ______.

Answer 5

second meiotic division

Question 6

Unlike most mammals, the canine oocyte ovulates at ______, before completion of meiosis 1, when it is not yet mature enough to be fertilized.

Answer 6

Prophase 1

Question 7

Cytoplasmic changes depend on close association between the oocyte and _____ _____ cells.

Answer 7

Corona radiata

Question 8

The cumulus mass is important for…

Answer 8

communication and response to stilumi

will be shed right before fertilization can take place

Question 9

Where does fertilization occur?

Answer 9

Ampulla of the uterine tube

Question 10

Removal of the _____ _____ removes additional chromosomes from the oocyte before fertilization.

Answer 10

Polar body

Question 11

Area that serves as a sperm reservoir in which sperm are released at intervals during ovulation to increase the chances of fertilization.

Answer 11

Isthmus of the uterine tube

Question 12

Capacitation

Answer 12

biochemical (not morphological) changes that take place in the female tract before sperm are capable of fertilization

Question 13

Steps in Capacitation

Answer 13

Changes in membrane cholesterol and glycosaminoglycans

Sperm become capable of undergoing acrosome reaction

Hypermotility

Oocyte receptor expression (allows species recognition)

Question 14

The acrosome reaction occurs upon contact with the ____ _______ and involves fusing of the sperm plasma membrane with the sperm outer acrosomal membrane.

Answer 14

zona pellucida

Question 15

The acrosome reaction allows SEQUENTIAL release of what?

Answer 15

acrosomal enzymes

Question 16

After a sperm cell attaches to and penetrates the zona pellucida, the ____ and ____ membranes fuse.

Answer 16

sperm and oocyte

Question 17

Specific protein binding site for sperm.

Answer 17

ZP3

Question 18

Acrosome reaction is _____ dependent.

Answer 18

calcium

Question 19

When does species recognition first occur?

Answer 19

At binding of sperm with the zona pellicida proteins

Question 20

Fusion of sperm membrane with the _____ occurs after the acrosome reaction is complete

Answer 20

oolemma (oocyte membrane) (vitelline membrane)

Question 21

Blocks to polyspermy occur at the zona pellucida by release of oocyte _____ _____ into the perivitelline space.

Answer 21

cortical granules

Question 22

After _____, the oocyte expels the second polar body.

Answer 22

penetration

Question 23

The male and female pronuclei have a _____ set of chromosomes and will come together within the ootid.

Answer 23

haploid

Question 24

The joining of the 2 pronuclei into one diploid cell is called

Answer 24

Syngamy

Question 25

Early divisions occur by ______, with no increase in size of the cell

Answer 25

cleavage

Question 26

What happens if polar bodies are not removed from the oocyte?

Answer 26

Incompatible with development. 3n. Can't do it.

Question 27

Fertilization and early cleavage takes place where?

Answer 27

uterine tube

Question 28

As fluid accumulates, the outer cells of the morula become flattened and a cavity known as the ______ is formed.

Answer 28

blastocoele

Question 29

How long until the zygote reaches the uterus?

Answer 29

cows and most others - 4 days horses - 6 days dogs - 8 days

Question 30

In the equine, the utero-tubal junction is closed to the zygote unless it can produce _____.

Answer 30

PGE2

Question 31

The inner cell mass forms

Answer 31

the embryo

Question 32

Cell other than those in the inner cell mass are responsible for forming

Answer 32

the placenta

Question 33

Only after _________ can formation of extraembryonic membranes occur.

Answer 33

maternal recognition of pregnancy

Question 34

extraembryonic membranes

Answer 34

yolk sac amnion chorion allantois

Question 35

Maternal recognition of pregnancy is critical in prolonging the function of the ____ _____.

Answer 35

Corpus luteum

Question 36

2 strategies of preserving the corpus luteum during pregnancy

Answer 36

Anti-luteolytic: diversion or inhibition of PGF2a Luteotropic: maintain CL (hCG in humans)

Question 37

In ruminants, after hatching from the zona pellucida, the blastocyst elongates and contacts the uterine luminal epithelium which induces production of _______.

Answer 37

IFNt (Interferon tau)

Question 38

IFNt in ruminants is responsible for maternal recognition of pregnancy and inhibits ______.

Answer 38

PGF2a

Question 39

In swine, maternal recognition of pregnancy is caused by the blastocyst producing ______, which then changes the path of PGF2a to the uterine lumen where it is deactivated.

Answer 39

estradiol

Question 40

In the equine, the ______ phase requires the embryo to move through both uterine horns several times per day to prevent loss of pregnancy.

Answer 40

mobility

Question 41

Polysaccharide-rich membrane unique to equids that preserves the round shape of the embryo, and maintains rigidity necessary for uterine migration.

Answer 41

Embryo capsule

Question 42

the embryo capsule disappears after __ days

Answer 42

23

Question 43

In Llamas, which uterine horn carries almost all of the pregnancies?

Answer 43

Left

Question 44

Recognition of pregnancy in the llama involves

Answer 44

Inhibition of PGF2a synthesis or release

Question 45

Recognition of pregnancy in the dog

Answer 45

Not needed. Diestrus lasts 60 days either way.

Question 46

Chorionic gonadotropins in the equine

Answer 46

eCG - produced in the endometrial cups

Question 47

Chorionic gonadotropins in the human

Answer 47

hCG - produced by the endometrium within 48 hours of fertilization