First Trimester Flashcards
the age of pregnancy calculated from 1st day of LMP
gestational age
the age of fetus calculated from fertilization;
2 weeks younger than gestational
conceptual age
through TVS the pregnancy can be identified _____ weeks earlier
1-2
weeks 2-8 of GA
embryonic period
more than 10 wks of gestation is known as
fetal period
a fertilized ovum by sperm is called a
zygote
when the zygote divides into two cells it is called a
blastomere; (cleavage ongoing cell division)
when a blastomere produces 12-16 cells it is called a
morula
product of conception is called
blastocyst
the blastocyst consists of the outer cell mass _____ and inner cell mass _______
trophoblast and embryoblast
the blastocyst will embed itself in the
secretory endometrium (thickening of uterine lining)
2 weeks after fertilization what develops
the bilaminar disc and the trilaminar disc
the _________ forms within the blastocyst. from two germ layers ______________.
bilaminar embryonic disc, endoderm (hypoblast) and ectoderm (epiblast).
the bilaminar disc turns into the __________ disc which holds the ___________________.
trilaminar disc, ectoderm, mesoderm and endoderm
what two cavities develop from the inner cell mass
amnion and primary yolk sac
trophoblasts differentiate into
cytotophoblast and syncytiotrophoblast
primary yolk sac and amniotic cavity was formed by the
embryoblast
cytotrophoblast and syncytiotrophoblast were formed by the
trophoblast
hCG produced by day 28
maintains the corpus luteum (progesterone) in order to prevent menstruation and maintain endometrial lining
blastocyst implantation has to do with the _____of the uterine cavity
lining
transformed endometrium of pregnancy is called
decidua
there are three types of decidua
basalis, capsularis, vera/parietalis
the endometrium lining the rest of the uterine cavity is called the
decidua vera/parietalis
the blastocyst is completely covered by the
decidua capsularis
what surrounds the embryo
amnion
what is the double bleb sign
amnion and yolk sac
amnion and yolk sac fuses with chorion by
12-16 wks
no fusion by chorion and yolk/amnion after more than 16wks is called
chorioamniotic separation
part of the connecting stalk of the embryo is the
allantois
the allantois gives rise to the
umbilical cord and bladder (urachus)
duct that connects embryo to yolk sac
viteline duct omphalomesenteric
the viteline duct gets mistaken for the
umbilical cord
echogenic ring of the gestational sac secretes hCG
chorion (extraembryonic coelom)
is a protein hormone secreted by placenta and present in pregnant womans urine and blood
hCG human chorionic gonadotropin
cytotrophoblastic cells of the blastocyst surround the embryo and eventually become the
placenta
responsible for hematopoiesis and transfer of nutrients
yolk sac
the _____ is identified sonographically by ____
yolk sac 5-6 wks
what distinguishes true GS from pseudosac(ectopic)
yolk sac
the yolk sac needs to measure
less than 6 mm
the yolk sac is perfectly ____ and has an ____ sonographic appearance
round, anechoic
the double decidual sac sign includes
decidua parietalis, decidua capsularis, decidua basalis
formula for mean sac diameter
sac L+W+H / 3 = (mm)
how to measure gestational days
MSD (mm) + 30 =
