Embryology 3

Question 1

the maternal-fetus circulation depends on ?

Answer 1

• a fetal cardiovascular system
• structures within the endometrium that allow exchange with the fetal cardiovascular system

Question 2

what are the types of chorionic villi?

Answer 2

• primary
• secondary
• tertiary

Question 3

when do you see primary chorionic villi?

Answer 3

present in week 2

Question 4

when do you see secondary chorionic villi?

Answer 4

present in week 3

Question 5

when do you see tertiary chorionic villi?

Answer 5

present by the end of week 3

Question 6

what are primary chorionic villi made out of?

Answer 6

only composed of cytotrophoblasts surrounded by a syncytiotrophoblastic shell

Question 7

what are secondary chorionic villi?

Answer 7

extraembryonic mesenchymal core surrounded cytotrophoblastic and synctiotrophoblastic shell

Question 8

what are tertiary chorionic villi?

Answer 8

• blood vessels (capillaries) within the mesenchymal core
  fetal blood can now exchange substances between the maternal lacuna through the membrane formed by the tertiary villus

Question 9

as the villi develop, the cytotrophoblast proliferates and extends through the synctiotrophoblast layer which forms?

Answer 9

cytotrophoblastic shell

Question 10

what does the cytotrophoblastic shell do?

Answer 10

it anchors the chorionic sac and attaches it to the endometrium

Question 11

what are anchoring villus?

Answer 11

a villus that attaches to the endometrium via cytotrophoblastic extensions

Question 12

what is the decidua?

Answer 12

the endometrium in a pregnant woman

Question 13

what are the 3 separate areas of the decidua?

Answer 13

• decidua basalis
• decidua capsularis
• decidua parietalis

Question 14

which decidua forms the placenta?

Answer 14

decidua basalis

Question 15

how is the decidua basalis connected to the embryo

Answer 15

by the umbilical cord

Question 16

which decidua does not include the basalis, but is still associated with/covers the embryo?

Answer 16

decidua capsularis

Question 17

which decidua is formed by the endometrium that is not part of the embryo?

Answer 17

decidua parietalis

Question 18

what is the smooth chorion?

Answer 18

the chorionic membrane that is associated with the decidua capsularis, the villi degenerate (don’t contact maternal blood)

Question 19

where is maternal blood found?

Answer 19

intervillous spaces

Question 20

what is vasculogenesis?

Answer 20

development of brand new blood vessels from mesoderm

Question 21

what is the angiogensis?

Answer 21

“sprouting” of blood vessels formed by vasculogenesis, connects blood vessels to each other

Question 22

angioblasts derived from mesoderm develop in specialized regions known as ?

Answer 22

blood islands

Question 23

what give rise to RBC?

Answer 23

angioblasts

Question 24

what is the dorsal aorta?

Answer 24

blood to the embryo and then connects to umbilical artery and cardinal veins

Question 25

what makes blood flow through the umbilical vesicle?

Answer 25

vitelline artery and vein

Question 26

what returns blood from tertiary villi back to the embryonic heart?

Answer 26

umbilical vein

Question 27

by the 4th week, the paired heart tubes have fused, resulting in?

Answer 27

a single ventricle and atrium