Embryology I

Question 1

What is the pre-embryonic stage?

Answer 1

weeks 1-2

Question 2

What is the embryonic stage?

Answer 2

weeks 3-8

Question 3

What is the fetal stage?

Answer 3

weeks 9-38

Question 4

What does the initial cleavage form?

Answer 4

morula

Question 5

What is formed after compaction?

Answer 5

blastocyst

Question 6

Where is oocyte fertilised?

Answer 6

ampulla

Question 7

Where is the fertilised egg implanted?

Answer 7

posterior uterine wall (high up)

Question 8

What coats the morula?

Answer 8

zona pellucida- glycoprotein coat

exclude other sperm

Question 9

What the first fluid filled cavity called?

Answer 9

blastocoele

Question 10

What the outer cell mass called? what cells does it provide?

Answer 10

trophoblast

cells for placenta

Question 11

What the inner cell mass called? what cells does it provide?

Answer 11

epiblast

all cells of the body

Question 12

What kind of cells doe the morula contain?

Answer 12

totipotent

Question 13

What kind of cells does the blastocyst contain?

Answer 13

pluripotent

Question 14

What happens on day 5?

Answer 14

blastocyst hatches from zona pellucida allowing enlargement and interaction with uterine surface

Question 15

In week two what layers form in outer cell mass?

Answer 15

synctiotrophoblast- multinucleated sheet invades endometrium
cytotrophoblast- forms skin cell layer

Question 16

What cavity is above the embryo at the end of week 2?

Answer 16

amniotic cavity

Question 17

What cavity is below the embryo at the end of week 2?

Answer 17

yolk sac

Question 18

What is the structure of maternal-fetal exchange called?

Answer 18

chorionic villus

Question 19

What happens if implantation occurs in the fallopian tube?

Answer 19

ectopic pregnancy

Question 20

What happens if implantation occurs in the lower uterine segment?

Answer 20

placenta praevia
haemorrage risk
c-section delivery required

Question 21

What is established when maternal sinusoids are invaded by synctiotrophoblast?

Answer 21

utero-placental circulation

Question 22

What forms between the yolk sac and the cytotrophoblast?

Answer 22

acellular extra-embryonic reticulum

Question 23

What does the extraembryonic reticulum convert to?

Answer 23

extra embryonic mesoderm

Question 24

What forms when spaces in extraembryonic mesoderm merge?

Answer 24

chorionic cavity

Question 25

What is the connecting stalk made from and what does it become later in development?

Answer 25

column mesoderm

future umbilical cord