10.1. Stages of pregnancy/Early embryonic dev't/ Implantation

Question 1

3 stages of pregnancy in female animals:

Answer 1

1. Period of ovum (shortest)
2. Period of embryo (intermediate or middle stage)
3. Period of fetus (longest)

Question 2

Characterized by zygote undergoing cell division

→ eventually forming the blastocyst and had
migrated from oviduct into the uterus
→ This cell division occurs from migration of the
zygote: from ampulla going to the uterus

Answer 2

period of OVUM

Question 3

Characterized by the free living stage of the
embryo

→ The zygote would undergo nidation or implantation in the uterus. There would be further
development of blastocysts, extraembryonic membranes, & placenta, differentiation of organ systems, and formation of appendages

Answer 3

Period of embryo (intermediate or middle stage)

Question 4

Since the placenta is only formed in this stage, so initially the embryo would subsists on the uterine fluids/milk

Answer 4

period of EMBRYO (intermediate or middle stage)

Question 5

→ Further characterized by the development of fetus & placenta
→ Last until the parturition stage

Answer 5

period of FETUS (longest)

Question 6

the zygote that would undergo ___ _____ as it migrates from the ampulla to the isthmus of oviduct.

Answer 6

cell division

Question 7

period of OVUM:

From a one-cell zygote, it would divide into a two cell → four cell → eight cell. It reaches the uterus at sixteen cell, forming the ________

Answer 7

morula

Question 8

period of OVUM:

By the time it reaches the uterus, prior to implantation, we do have the blastocyst stage of the embryo. This blastocyst contains the ____ ____ ____ that would eventually form the embryo.

Answer 8

inner cell mass

Question 9

Zygote remains in the oviduct for __to__ days before
its transport to the uterus

Answer 9

3-5 days

Question 10

The migration of the zygote from the ampulla, leading to cell division of the zygote (from two cell → four cell → eight cell → sixteen cell → morula).

By the time it reaches the
uterus, it becomes the ____ stage of the zygote

Answer 10

blastocyst stage

Question 11

only (2) animals who’s duration of transport to uterus after conception is different

the rest is 3-4 days

Answer 11

1. bitch (5-6 days)
2. queen (4 days)

Question 12

Time of Implantation after
conception of every animal?

all animals have different answer

Answer 12

bitch = 15 days
queen = 13 days
cow = 18-22 days
ewe = 15-18 days
sow = 14-20 days
mare = 30-35 days

Question 13

which animal has the LONGEST duration of transport?

Answer 13

BITCH (5-6 days)

Question 14

Implantation of blastocyst (1):

What attaches the endometrium would be the side of the blastocyst
containing the ___ ___ ___.

Answer 14

inner cell mass

Question 15

Implantation of blastocyst (2):

Eventually, the connection or attachment between the ______ of the uterus and the ______ is seen

Answer 15

endometrium
blastocyst

Question 16

Implantation of blastocyst (3):

The formation
or development of the ___, and _____

Answer 16

fetus & placenta

Question 17

Maternal Recognition of Pregnancy/Gestation:

For SOW, requires at least 4 piglets implanted in the 2 uterine horns

Answer 17

presence of
EMBRYO in the
uterus

Question 18

Maternal Recognition of Pregnancy/Gestation:

for MARE – embryo moves throughout both uterine horns from days 12-17

for COW – embryo moves in uterine horn with ipsilateral CL

for Litter bearing animals – spacing of fetuses between the 2 uterine horns

Answer 18

Interaction of embryo with the endometrium

Question 19

In mare, they move out throughout both uterine horns from days ___to___

Answer 19

12-17

Question 20

In cow, the embryo moves IN uterine horn within the

Answer 20

ipsilateral CL