22 - Applied Embryology

Question 1

what happens during day 1 of early embryo development?

Answer 1

formation of pronuclei

Question 2

what happens during day 2 of early embryo development?

Answer 2

first cell division

Question 3

what happens during day 3 of early embryo development?

Answer 3

cell division continues

Question 4

what happens during day 4 of early embryo development?

Answer 4

formation of morula

Question 5

what happens during day 5 of early embryo development?

Answer 5

blastocyst forms

Question 6

4 components of the mature placenta?

Answer 6

Chorionic villi

The intervillous space

Placental Septae

Cotyledons

Question 7

name 5 functions of the placenta?

Answer 7

Acts as an immunological barrier

Gas exchange

Nutrient exchange

Waste excretion

Endocrine functions

Question 8

when does the mesoderm form?

Answer 8

day 12

Question 9

when does the mesoderm spreading occur?

Answer 9

day 18

Question 10

when does the amniotic sac enlargement occur?

Answer 10

day 23

Question 11

where does the primitive streak develop?

Answer 11

caudal end of the embryo

Question 12

what form the endoderm?

Answer 12

epiblast cells migrating into the hypoblast layer

Question 13

how is the mesoderm formed?

Answer 13

epiblast cells migrate thought the primitive streak between the epiblast and hypoblast

Question 14

where does the notochord develop?

Answer 14

develops cranially from just above the primitive streak

Question 15

what are the two small areas at either end of the embryo without any mesoderm?

Answer 15

buccopharyngeal membrane

cloacal membrane

Question 16

name 4 cell lines who are formed from ectoderm?

Answer 16

Epidermis

central nervous system

peripheral nervous system

hair

Question 17

name 4 cell lines who are formed from mesoderm?

Answer 17

Dermis

musculoskeletal structures

cardiovascular system

gonads

Question 18

name 4 cell lines who are formed from endoderm?

Answer 18

Lining of the gastrointestinal tract

the parenchyma of the liver

pancreas

thyroid

Question 19

what is a neural plate?

Answer 19

thickening of ectoderm over the notochord

Question 20

what does the neural plate become as it thickens?

Answer 20

neural groove

Question 21

what do neural crest cells contribute to?

Answer 21

PNS

Question 22

3 subunits of the mesoderm?

Answer 22

Paraxial Mesoderm

Intermidiate Mesoderm

Lateral Plate Mesoderm

Question 23

what does the paraxial mesoderm form?

Answer 23

somites

Question 24

what are the 2 subunits of the somites?

Answer 24

dermomyotomes

sclerotomes

Question 25

how many occipital somites are there?

Answer 25

4

Question 26

how many cervical somites are there?

Answer 26

8

Question 27

how many thoracic somites are there?

Answer 27

12

Question 28

how many lumbar somites are there?

Answer 28

5

Question 29

how many sacral somites are there?

Answer 29

5

Question 30

how many coccygeal somites are there?

Answer 30

8-10

Question 31

what 3 structures does the intermediate mesoderm give rise to?

Answer 31

kidneys ureters gonads

Question 32

what 5 structures does the lateral plate mesoderm give rise to?

Answer 32

pleura pericardium peritoneum cardiovascular system connective tissues & smooth muscle of GI and resp systems

Question 33

during what week does the following occur - Pharangeal Arches form Neural tube is fusing, initial structures of the brain form Upper limb buds, then lower limb buds form The heart begins to beat The primordial gut is forming The beginnings of the lower respiratory tract forms

Answer 33

4

Question 34

during what week does the following occur - Upper limbs are divided into definite regions Digital rays are forming External Ear is forming Some movements visible

Answer 34

6

Question 35

during what week does the following occur - The fingers begin to separate The gut herniates into the umbilical cord

Answer 35

7

Question 36

during what week does the following occur - Fingers are separated but webbed Toes are beginning to separate The head is significantly larger The eye is pigmented

Answer 36

8

Question 37

when does the embryonic phase end and so foetal period begin?

Answer 37

beyond week 8

Question 38

what is the incidence of natural multiple pregnancies in UK?

Answer 38

1:80

Question 39

what is the difference in cause of non-identical twins and identical twins?

Answer 39

non-identical - multiple eggs fertilising and implanting identical - embryo splits

Question 40

what are the three stages of the development of the kidney?

Answer 40

The pronephros (non-functional) The mesonephros (functional but transient) The metanephros (final kidney)

Question 41

what is the cloaca and what divides it?

Answer 41

caudal end of the enfolded yolk sac - divided by the urorectal septum

Question 42

what does the divided cloaca form?

Answer 42

The urogenital sinus The anal canal

Question 43

what structure goes on to form the bladder and urethra?

Answer 43

urogenital sinus

Question 44

which chromosome contains the SRY gene?

Answer 44

Y

Question 45

what are the 2 sets of genital tracts?

Answer 45

Mesonephric Duct Paramesonephric Duct

Question 46

what determines which genital tract develops and which regresses?

Answer 46

presence or absence of AMH (Anti-Mullerian hormone)

Question 47

what does presence of AMH cause in the male?

Answer 47

paramesonephric ducts regress

Question 48

which association can often be made with women who have reproductive tract anomalies?

Answer 48

renal tract anomalies

Question 49

what classification is used for congenital defects in female reprodcutive tract?

Answer 49

ASRM