Mod.A Embryology Lec3

Question 1

the zygote undergoes a series of mitotic divisions resulting in

Answer 1

blastomeres

Question 2

when are blastomeres formed ?

Answer 2

Approximately 30 hours after fertilization and formation of zygote

Question 3

when is the compacted embryo/a morula is formed

Answer 3

After the eight-cell stage, when there are 12 to 32 blastomeres

Question 4

what’s the point of cell compaction ?

Answer 4

Compaction permits greater cell-to-cell interaction and is a

prerequisite for formation of the inner cell mass or embryoblast

Question 5

Shortly after the morula enters the uterus, uterine fluid passes
through the zona pellucida to form a fluid-filled space

Answer 5

the blastocystic cavity

Question 6

when is the embryo called blastocyst ?

Answer 6

when the blastocystic cavity is formed

Question 7

As fluid increases in the blastocystic cavity, the blastomeres are separated into
two parts

Answer 7

The embryoblast or inner cell mass

a discrete group of
blastomeres that is the primordium of the embryo

the trophoblast

the thin outer cells that give rise to the embryonic
part of the placenta

Question 8

the blastocyst attaches
to the endometrial epithelium. The trophoblast differentiate into
two layers, when does this process happen ?

Answer 8

6 days after fertilization

Question 9

Implantation of the blastocyst begins at the

Answer 9

end of the 1st week (5-6-7) days

Question 10

implantation occurs in

Answer 10

endometrium, usually superiorly in the
body of the uterus (near the funds) and slightly more often on the
posterior than on the anterior wall

Question 11

after implantation the endometrium is called

Answer 11

decidua

Question 12

when is the embryo completely embedded in the endometrium ?

Answer 12

at the 10th day (2nd week)

Question 13

The syncytiotrophoblast produces a hormone

Answer 13

human chorionic gonadotropin (hCG), which enters the maternal blood

Question 14

function of hCG

Answer 14

maintains the development of arteries in the myometrium
and formation of the syncytiotrophoblast

hCG also forms the basis for pregnancy tests.

Question 15

as the process of implantation takes place, changes occur produdcing

Answer 15

bilaminar embryonic disc composed of two layers, the epiblast
(primary ectoderm) and hypoblast (primary endoderm)

Question 16

when are Extraembryonic structures formed?

Answer 16

during second week

Question 17

Extraembryonic structures

Answer 17

amniotic cavity, amnion, umbilical vesicle (yolk sac),

connecting stalk, and chorionic sac

Question 18

Decidua means

Answer 18

the endometrium of the uterus after
implantation, which is the functional layer of the endometrium in a
pregnant woman that separates from the reminder of the uterus
after childbirth

Question 19

regions of decidua

Answer 19

Decidua basalis, Decidua capsularis, Decidua parietalis

Question 20

decidual reaction

Answer 20

The cellular and vascular changes in the decidua that result from
pregnancy

Question 21

Occasionally, implantation takes place outside the uterus,

resulting in

Answer 21

extrauterine pregnancy, or ectopic pregnancy

Question 22

Ectopic pregnancies may occur at any place in

Answer 22

he abdominal
cavity,

ovary,

or uterine tube

Question 23

95% of ectopic pregnancies occur in the

Answer 23

uterine tube

called tubal pregnancy, and most of these are in the ampulla

Question 24

Interstitial pregnancy

Answer 24

Due to
implantation in the narrow portion of
the uterine tube.

Question 25

Ovarian pregnancy

Answer 25

Due to

implantation in the ovary

Question 26

Abdominal pregnancy

Answer 26

Due to
implantation into the peritoneum as
the blastocyst most frequently
attaches itself to the peritoneal lining
of the rectouterine cavity. The
blastocyst may also attach itself to the
peritoneal covering of the intestinal
tract or to the omentum

Question 27

Cervical pregnancy:

Answer 27

Due to

implantation in the cervix of the uterus