early fetal dvpmt

Question 1

day 0- what 3 things happen?

Answer 1

1. fert. by sperm
2. form zygote
3. initiate embryogenesis

Question 2

what happens within 1 wk of fertilization?

Answer 2

hCG secretion begins after implantation of blastocyst

Question 3

what happens w/in 2 wks of fert?

Answer 3

bilaminar disc (hypoblast/epiblast). 
- 2 wks = 2 layers

Question 4

what are the two layers of the bilaminer disc and when do they dvp?

Answer 4

hypoblast and epiblast

dvp w/in 2 wks (2 wks = 2 layers!)

Question 5

what happens w/in 3 wks of fert?

Answer 5

Trilaminar disc (3 wks = 3 layers)
gastrulation
primitive streak, notochord, mesoderm and it’s organization/neuronal plate begin to form

Question 6

during which week does primitive streak, notochord, mesoderm and it’s organization/neuronal plate begin to form?

Answer 6

w/in wk 3

Question 7

what happens during wks 3-8 of dvpmt, aka embryonic period (2 things)

Answer 7

1. neural tube = formed by neuroectoderm and closes by wk 4

2. organogenesis - NOTE extremely susceptible to teratogens

Question 8

neural tube = formed by neuroectoderm and closes by

Answer 8

wk 4

Question 9

fetus = most susceptible to teratogens during…

Answer 9

wk 3-8 - organogenesis

Question 10

what happens in wk 8?

Answer 10

Start of fetal period- fetal mvmt and fetus looks like a baby

Question 11

when is embryogenic period? when does fetal period start?

Answer 11

embryogenic - wk 3-8

fetal - starts wk 8

Question 12

when do fetuses have male/fm characteristics?

Answer 12

wk 10

Question 13

what is gastrulation?

Answer 13

process that forms trilaminar embryonic disc- establishes ectoderm, mesoderm and endoderm

Question 14

gastrulation starts w/…

Answer 14

epiblast invagination to form primitive streak

Question 15

epiblast invagination to form primitive streak = start of…

Answer 15

gastrulation

Question 16

absent organ due to absent primordial tissue =

Answer 16

agenesis

Question 17

absent organ despite present primordial tissue =

Answer 17

aplasia

Question 18

extrinsic disruption; occurs after embryonic period =

Answer 18

deformation

Question 19

incomplete organ dvpmt; primordial tissue = present =

Answer 19

hypoplasia

Question 20

intrinsic disruption; occurs during the embryonic period (wks 3-8) =

Answer 20

malformation

Question 21

when is the “all or none” effect of teratogens? the most susceptible period? when is growth and function affected by teratogens?

Answer 21

“all or none” effect: wks 0-3
most susceptible: 3-8
growth/func: after wk 8

Question 22

alkylating agents can cause what defects in uterus?

Answer 22

absent digits/multiple anomalies

Question 23

which drug can cause neural tube defects, craniofacial defects, fingernail hypoplasia, dvpmt delay, IUGR?

Answer 23

carbamezapine

Question 24

which drug causes fetal hydantoin syndrome: microcephaly, dysmorphic craniofacial features, hypoplastic nails/distal phalanges, cardiac defects, IUGR and mental retardation

Answer 24

Phenytoin

Question 25

teratogenic effects of warfarin (4)

Answer 25

bone deformities
fetal hemorrhage
abortion
opthalmologic abnormalities

Question 26

cocaine causes…

Answer 26

1. placental abruption/premature birth

2. fetal addiction

Question 27

smoking (nicotine, CO) causes…

Answer 27

preterm labor
placental probs
IUGR (intrauterine growth retardation)
ADHD

Question 28

congenital goiter/hypothyroidism in infant can be caused by…

Answer 28

Iodide defic or excess

Question 29

agenesis of the sacrum & lumbar spine, flacid paralysis of the legs, dorsiflexed contractures of foot and urinary incontinence in the baby (ie caudal regression syndrome) can be caused by…

Answer 29

maternal diabetes

Question 30

excess of what vitamin causes high risk of spontaneous abortions/birth defects (cleft palate, cardiac anomalies)

Answer 30

vit A

Question 31

maternal diabetes can lead to (3)

Answer 31

1. caudal regression syndrome (anal atresia to sirenomelia)
2. congenital heart defects
3. neural tube defects

Question 32

x-rays can lead to

Answer 32

microcephaly and mental retardation

Question 33

dizygotic twins are always (in terms of amnio and placenta)

Answer 33

dichorionic, diamniotic

Question 34

most monozygotic twins = (in terms of amnio and placenta)

Answer 34

monochorio, diamnio (split btween 4 and 8 days)

Question 35

if monozygotic twins split btwn 0-4 days, how many placentas/amnio sacs?

Answer 35

dichorio, diamnios

Question 36

if monozygotic twins split btwn 4-8 days, how many placentas/amnios?

Answer 36

monochorio, diamnio

twins will share food before they’ll share a bed– ie share the placenta before their amnio sac

Question 37

if monozygotic twins split btwn 8-12 days, how many placentas/amnio sacs?

Answer 37

monochorio, monoamnio

Question 38

if monozygotic twins split after 13 days…

Answer 38

monochorio, monoamnio CONJOINED twins