Embryology 3 - The Early Fetal-Maternal Circulation

Question 1

By the 4th week, what has the growth of the embryo and chorion resulted in?

Answer 1

Diffusion of nutrients between the embryo and endometrium being INADEQUATE

Question 2

What day does the embryonic heart begin to beat?

Answer 2

Day 21

Question 3

What are present in the embryo by day 21?

Answer 3

Blood vessels and RBCs

Question 4

What two things does maternal-fetal circulation depend on?

Answer 4

1. Fetal cardiovascular system
2. Structures in endometrium that allow exchange to happen

Question 5

What are primary chorionic villi composed of?

Answer 5

Cytotrophoblasts surrounded by synctiotrophoblastic shell

Question 6

What are secondary chorionic villi composed of?

Answer 6

Extraembryonic mesenchymal core surrounded cytotrophoblastic AND syncytiotrophoblastic shell

Question 7

When are tertiary chorionic villi present?

Answer 7

By the end of week 3

Question 8

Because of tertiary chorionic villi, fetal blood can now exchange blood with maternal _______ through the membrane formed by the villus

Answer 8

Lacuna

Question 9

As the villi develop, what is formed as the cytotrophoblast proliferates and extends through the syncytiotrophoblast layer?

Answer 9

Cytotrophoblastic shell

Question 10

What is the function of the cytotrophoblastic shell?

Answer 10

Anchors the chorionic sac and attaches it to the endometrium

Question 11

What is an anchoring villus?

Answer 11

villus that attaches to endometrium via cytotrophoblastic extensions

Question 12

That is the endometrium in a pregnant woman?

Answer 12

decidua

Question 13

What are the 3 separate areas of the decidua?

Answer 13

1. Decidua basalis
2. Decidua capsularis
3. Decidua parietalis

Question 14

The decidua that forms the placenta, thats connected to the embryo by the umbilical cord?

Answer 14

Decidua basalis

Question 15

The decidua that doesn’t include the basalis, but is still associated with/covers the embryo?

Answer 15

Decidua capsularis

Question 16

Decidua that is formed by the endometrium that is not a part of the embryo (far from implantation site)?

Answer 16

Decidua parietalis

Question 17

The chorionic membrane that is associated with the decidua capsularis?

Answer 17

Smooth chorion

Question 18

Where is maternal blood found in the pregnant uterus?

Answer 18

Intervillous spaces

Question 19

Where does the development of the fetal cardiovascular system begin?

Answer 19

Umbilical vesicle and neighbouring connecting stalk

Question 20

When does fetal cardiovascular system begin to develop?

Answer 20

Early in the 3rd week

Question 21

What is vasculogenesis?

Answer 21

Development of brand new blood vessels from mesoderm

Question 22

What is angiogenesis?

Answer 22

sprouting of blood vessels formed by vasculogenesis - connects blood vessels to each other

Question 23

Angioblasts derives from ______ develop specialized regions known as ________

Answer 23

Mesoderm; blood islands

Question 24

What is the process of blood islands developing luen and becoming blood vessels called?

Answer 24

Vasculogenesis

Question 25

Blood cells are derived from the what of the new vessels?

Answer 25

Inner lining (endothelium)

Question 26

Extraembryonically, what do blood cells develop from?

Answer 26

Endothelium of allantois and umbilical vesicle

Question 27

Intraembryonically, what do blood cells develop from?

Answer 27

Endothelium of dorsal aorta

Question 28

Within the embryo, the formation of angioblastic cords (vasculogenesis) occurs where during gastrulation/nurulation?

Answer 28

Mesenchyme

Question 29

The caudal head fold brings the paired heart tubes ______ toward the _______

Answer 29

Caudally, toward the umbilical vesicle

Question 30

When do the heart tubes fuse to from a primordial heart tube?

Answer 30

At the end of the third week

Question 31

What does the intraembryonic coelom near the heart tube develop into?

Answer 31

The Pericardial Cavity

Question 32

Vessel that supplies blood to the embryo and then connects to the umbilical artery and cardinal veins?

Answer 32

Dorsal aorta

Question 33

The flow from dorsal aorta to cardinal veins feeds what?

Answer 33

Intraembryonic tissues

Question 34

Vessel responsible for Blood flow through the umbilical vesicle?

Answer 34

Vitelline artery and vein

Question 35

vessel that returns blood from the tertiary villi back to the embryonic heart?

Answer 35

Umbilical vein