Fetal Development Flashcards
fertilization=
conception
def zygote
sperm fuses w/ an ovum to form a new diploid cell
after the union of the 2 gametes, the zygote will contain how many chromosomes
46
when is the sex of the baby determined
@ the moment of fertilization
cell division occurs via
rapid mitosis
when does a blastocyst form?
3 days after fertilization
patho of blastocyst
- blastocyst implants into the endometrium and sarronds itself in maternal tissue
- inner cell mass of blastocyst develops into embryo
when does implantation occur?
7-10 days after fertilization
-approx day 22/23rd day of 28 day cycle
implantation causes which hormone to be secreted
HCG
is there a (+) preg test when implantation occurs
no- not yet
which bodily fluid picks up HCG fastest
blood
when will a mom get a (+) preg test
4 weeks
the first day of LMP is used to determine
due date
gest age
when is the embryonic period
3-8 wk of preg after conception
what development occurs during the embryonic period
- basic structures of all major organs completed
- tissues differentiate into essential organs
when is a baby most vulnerable to teratogens
embryonic period
a baby is considered a fetus after the ____ wk
8th
when is the CNS and heart developing/developed
3rd wk
when is external genitalia developed
8-9 wk
when does the brain begin to develop
wk 9-16
how often does HCG rise during preg?
q 24 h
def implantation bleeding
bleeding occurs when egg burrows into the endometrial wall
implanation bleeding is AKA
implantation spotting
what color is blood when implantation bleeding occurs
light red/pink
the flickering of a heart can be heard when and through what method
end of wk 6
US
length of fetal period
9 wks to birth
at 8 wks, you can hear the fetal heart beat via
vaginal US
when is the best time to date a preg
8 wks
what measurement is taken at 8 weeks
crown-rump measurement
fetal heartbeat can be detected by ____ @ 12 wks
doppler
external genitalia can be distinguished
8-12 wks
when does lanugo begin to develop
8-12 wks
when can the sex of the baby be determined
17-21 wks
quickening can be perceived by mom as early as
16 wks
quickening must be perceived by which week
20th week
vernix caseosa covers skin during which weeks
16-20 wks
brown fat production is completed by
20 wks
purpose of brown fat
- keeps baby warm in utero
- helps provide nourishment for newborn while mothers milk is still descending/producing
if the fetus were born during this week, it would be possible for it to survive
24 wks
what is happening at 24 wks gestation
- lung alveoli beginning to form
- surfactant production begins in lungs
- gas exchange possible
- fetal resp mvmts
fetal resp mvmts
can see chest of fetus move up and down on US
expanding and contracting
baby is practicing breathing
the baby has a much better chance of survival of born during which week
28th week
eyes open and close after how many wks gestation
26 wks
gestational development at 32 weeks
- rhythmic breathing mvmts
- ability to control temp
gestational dev at 38 wks
- well developed ability to exchange gas
- lanugo on back and shoulders only
- vernix present in major body creases
auxiliary structures/organs
placenta
umbilical cord
fetal membranes- amniotic sac
amniotic fluid
T/F- the placenta is the interface bx mother and fetus
true
metabolic fx of the placenta
- substances synthesized into
glycogen
chol
carbs
fatty acidwhat is the key fx of the placenta
respiration/gas exchange by simple diffusion
placenta as the transfer organ
o2
nutrients
waste products
AB’s
T/F- placenta stores nutrients
true
when does HCG become present in blood
8-10 days after fertilization
when does HCG become present in urine
at time of missed menses
fx of progesterone during preg
- causes endometrium to change into the decidua
- decreases contractility of the uterus
- suppresses maternal rxns to fetal antigens that cause SAB
def decidua
provides nourishment for the early conceptus
what hormone must be present for implantation to occur
progesterone
what hormone can be given to prospective moms if they are having trouble getting/ staying pregnant
progesterone
fx of estrogen during preg
- enlargement of breasts, uterus, and external genitalia
- enhances uterine activity as due date approaches
what is HPL
human placental lactogen
fx’s of HPL
- promotes nutrition and fetal growth
- decr maternal insulin sensitivity and utilization of glucose—> making more glucose available for fetal growth
- maternal breast development to support lactation
bv’s of the umbilical cord
2 arteries
1 vein
what is wharton’s jelly
sarrounds the bv’s in the umbilical cord
when does the amniotic sac form?
at time of implantation
layers of the amniotic sac
- amnion
- chorion
amnion
- inner membrane of amniotic sac
- contains amniotic fluid
chorion
-outer membrane of the amniotic sac
what is chorio
infec of the chorionic membrane
what are mom and baby at risk for if the chorionic sac membrane is ruptured
infec
amniotic fluid____ in vol throughout the preg
increases
what is the normal vol range of amniotic fluid after 20 wks gestation
700-1000 mL
fx of amniotic fluid
- thermoreg of fluid
- symmetrical growth and dev of fetus
- cushions and protects fetus
- protects umbilical cord
what measurement is important to determine fetal well being
volume of amniotic fluid
oligohydramnios
leak of amniotic fluid
polyhydramnios
may indicate that the baby is not swallowing
—-> may indicate baby GI distress/disfx
likelihood of having twins increases with
maternal age
