Embryology Md1 Block 2 Placenta Part1

Front 1

chorion is the portion of

Back 1

fetal membrane that eventually forms the fetal side of the placenta.

Front 2

Chorion is formed by

Back 2

extraembryonic mesoderm
and the two layers of trophoblast

Hint 2

It is formed by extraembryonic mesoderm(visceral) and the two layers of trophoblast and surrounds the embryo and other membranes.

Front 3

The chorion is divided into the smooth chorion and the villous chorion. The villous chorion forms the ___________ =

Back 3

placenta

Front 4

The chorionic villi emerge from the chorion, invade the

Back 4

endometrium

Front 5

The chorion undergoes rapid proliferation and forms numerous processes, the chorionic villi, which invade the+

Back 5

uterine decidua.

Front 6

The chorion contains _____ ______

Back 6

chorionic villi,

These villi are snipped or suctioned off for study in the procedure.

Since the chorionic villi are of ______ ________

Hint 6

fetal origin,

examining samples of them can provide the genetic makeup of the fetus.

Front 7

CVS (chorionic villus sampling)

The test can be done before amniocentesis, about __ - __ = wks

Back 7

6-11 weeks

10-12th week, after a missed period.

Front 8

- the functional layer of the endometrium in a pregnant woman. is aka =

Back 8

Decidua
refers to the gravid endometrium

Front 9

________ is the term for the endometrium during a pregnancy

Back 9

Decidua

, which forms the maternal part of the ____________ =

Hint 9

placenta

Front 10

The three regions of the decidua are named according to their relation to the implantation site

Back 10

decidua basalis
decidua capsularis
decidua parietalis

info

Hint 10

The decidua basalis is the part of the decidua deep to the conceptus that forms the maternal part of the placenta

The decidua capsularis is the superficial part of the decidua overlying the conceptus

The decidua parietalis is all the remaining parts of the decidua

Front 11

the part of the decidua deep to the conceptus that forms the maternal part of the placenta

Back 11

decidua basalis

Front 12

umbilical cord comes from the same zygote as the fetus

Umbilical Cord normally contains =

Back 12

two arteries

one vein

Front 13

umbilical cord develops from and contains remnants of the

Back 13

yolk sac and allantois


info

Hint 13

and is therefore derived from the same zygote as the fetus).

Front 14

umbilical cord
forms by the ______ week of fetal development,

Back 14

5th wk

replacing the yolk sac as the source of nutrients for the fetus.The

Front 15

, the umbilical vein continues towards the transverse fissure of the

Back 15

liver


One of these branches joins with the


The second branch (known as the

Hint 15

hepatic portal vein (connecting to its left branch


ductus venosus

Front 16

the majority of the incoming blood (approximately 80%) to bypass the liver and flow via the

Back 16

left hepatic vein

into the inferior vena cava, which carries blood towards the heart.

Front 17

The two umbilical arteries branch from the

Back 17

the internal iliac arteries, and pass on either side of the urinary bladder before joining the umbilical cord.

Front 18

, the umbilical vein and ductus venosus close up, and degenerate into fibrous remnants known as the
=
2ct

Back 18

round ligament of the liver

the ligamentum venosum

Front 19

WHAT IS THE MEDIAL LIGAMENT CALLED =

DESCRIBE IT =

Back 19

.Urachus

fetal canal connecting the bladder with the allantois, persisting throughout life as a cord (median umbilical ligament).

Front 20

Development of Placenta

By the end of the __ wk =

Back 20

, the anatomical arrangements necessary for physiological exchanges between the mother and embryo are established.

Front 21

Development of Placenta

A complex vascular network is established in the placenta by the end of the
which facilitates maternal-embryonic exchanges of gases, nutrients, and metabolic waste products.

Back 21

4th wk

Front 22

Chorionic villi
cover the entire chorionic sac until the beginning of the __ wk =

Back 22

8th

As this sac grows, the villi associated with the decidua capsularis are compressed, reducing the blood supply to them.

These villi soon degenerate, producing a relatively avascular bare area, the ______ ________ =

Hint 22

smooth chorion.

Front 23

This bushy part of the chorionic sac is the ______ ________ =

Back 23

villous chorion.

Front 24

The fully developed placenta covers ____ to _____ % of the decidua

Back 24

15 to 30%
of the decidua

Front 25

The placenta has two parts

Back 25

The fetal part of the placenta :

The maternal part of the placenta :

Front 26

The fetal part of the placenta :
Formed by the =

Back 26

villous chorion

The chorionic villi that arise from it project into the intervillous space containing maternal blood

Front 27

The maternal part of the placenta :
Formed by the =

Back 27

Formed by the decidua basalis,

the part of the decidua related to the fetal component of the placenta
By the end of the fourth month, the decidua basalis is almost entirely replaced by the fetal part of the placenta.

Front 28

Info

Endometrial arteries and veins pass freely through gaps in the cytotrophoblastic shell and open into the intervillous space. ( The intervillis space is where maternal blood goes and diffusion occurs there in the shell.)

Back 28

.

Front 29

It is through the numerous _______ ______ which arise from stem villi, that the main exchange of material between mother and fetus takes place.

Back 29

branch villi,

Front 30

Placental circulation

2ct

Back 30

Fetal Placental Circulation

Maternal placental circulation

Front 31

Poorly oxygenated blood leaves the fetus and passes through the

Back 31

umbilical arteries

Front 32

chorionic arteries that branch freely in the _______ _______ to the placenta.

Back 32

umbilical arteries

Front 33

At the site of attachment of the umbilical cord to the placenta, these arteries divide into several radially disposed ________ _______

Back 33

chorionic arteries

Front 34

The blood vessels form an extensive arterio-capillary-venous system within the _____ ________ , which brings the fetal blood extremely close to the maternal blood.

Back 34

within the chorionic villi,

Front 35

T/F

There is normally intermingling of fetal and maternal blood.

Back 35

F

Front 36

Maternal placental circulation

These vessels discharge into the intervillous space through gaps in the

Back 36

cytotrophoblastic shell.

Front 37

Info

Reductions of uteroplacental circulation result in fetal hypoxia and IUGR.

Severe reductions of uteroplacental circulation may result in fetal death.

Back 37

.

Front 38

The intervillous space of the mature placenta contains about 150 ml of blood that is replenished ____ ____ ____ ______ per minute.

Back 38

maternal blood from fetal blood.

info

Hint 38

The composition of the placental membrane changes during pregnancy.

Front 39

A. In early pregnancy, the placental membrane has 4 layers:

Back 39

Syncytiotrophoblast
Cytotrophoblast
Connective tissue,
Endothelium of fetal capillaries

Front 40

_______ _______(large, sometimes pigmented, elliptical cells found in connective tissue) are most numerous in early pregnancy and have characteristics similar to those of macrophages

Back 40

Hofbauer cells

Front 41

The placenta has three main functions
3ct

Back 41

Metabolism
Transport of gases and nutrients
Endocrine secretion