1st Trimester & Terminology Flashcards
This is the villi on thematernal side of hte embryo; unites with the chorion to form the placenta.
decidua basalis
This is the villi surrounding the chorionic sad.
decidua capsularis
MSD stands for…
mean sac diameter.
This is the fetal trophoblastic tissue that, together with the decidua, form the area for maternal and fetal circulation.
chorion frondosum
This is the chorion around the gestational sac on the opposide side of implantation.
chorion laeve
This is the fetal suface of the placenta.
chorionic plate
This is the maternal surface of the placenta.
basal plate
The four sims of first trimester sonography are…
- confirm viability
- accuractely date the pregnancy
- diagnose multiple preganancies
- investigate complications
Early in the mentrual cycle, the ___ secretes rising levels of FSH and LH, which cause the growth of follicles.
pituitary gland
Early in the mentrual cycle, the pituitary gland secretes rising levels of ___, which cause the growth of follicles.
FSH and LH
This is the follicle that becomes dominant.
mature or Graafian follicle
The developing follicles produce ___.
estrogen
After ovulation, the follicle collapses to form the ___, which secretes progesterone and estrogen.
corpus luteum
After ovulation, the follicle collapses to form the corpus luteum, which secretes ___.
progesterone and estrogen
This is the outer layer of cells of the gestational or chorionic sac that secretes hCG.
syncytiotrophoblast
___ stimulate endometial cellular proliferation in preparation for implantation.
Progesterone and estrogen
Progesterone and estrogen stimulate ___ in preparation for implantation.
endometial cellular proliferation
These changes occur as a hormonal reponse regardless of the site of implantation.
decidual reaction
How many sperm are deposited during intercourse?
200-600 million
Fertilization usually occurs within __ after ovulation in the ___ portion of the fallopian tube.
24-36 hours, ampullary
This is the outer layer of the ovum.
zona pellucida
This is the inner cell layer of the developing embryo.
cytotrophoblast
This is a ball of 16 cells surrounded by the zona pellucida tranported to the uterus.
morula
Thisis the organized collection of cells that buries into th endometrial tissue about 7 days after fertilization.
blastocyst
Which is the inner layer of the embryonic disc?
endoderm
Which is the middle layer of the embryonic disc?
mesoderm
Which is the outer layer of the embryonic disc?
ectoderm
By what day is implantation complete?
day 23
Implantation usually occurs in the ___ region of the uterus.
fundal
The 3 distinct layers of decidualized endometrium are…
decidua capsularis, basalis, and parietalis (vera)
Why is it important to identify the doulble-decidual sign in early pregnancy?
To rule out ectopic.
The fusion of the amnion and chorion is usually complete by…
12-16 weeks
At 23 days the entire conceptus measures approximately ___ in diameter.
0.1 mm
T/F? At 23 days the conceptus can be seen transvag but not transab.
FALSE, it is not visible yet either way.
This is the formation of the neural plate and its closure to form the neural tube.
neurulation
The process of neurulation begins in the ___ week.
5th
Nearly all congenital malformations, except for genitalia abnormalities, originate before or during this ___ period.
embryonic
T/F? hCG is detectable in maternal serum, but not urine.
FALSE, both
hCG is first detected ___ weeks after LMP or ___ days after ovulation.
3, 7-10
hCG doubles every ___ days?
2-3
hCG plateaus around ___ weeks, then declines.
8-9
Which kind of pregnancy test is qualitative?
urine test, just a + or -.
Which kind of pregnancy test is quantitative?
blood test, +/- AND how far along
Which protein does a blood pregnancy test measure?
AFP which is produced by the fetal liver
Greater than expected AFP levels are associated with…
incorrect dates, gestational trophoblastic disease, or multiple gestations.
Less than expected AFP levels are associated with…
incorrect dates, ectopic, or embryonic demise.
A disproportionately low B-hCG level is considered to be…
an indicator of a poor prognosis.
The most common radioimmunassay method used is…
2IRP.
This is the first sonographic evidence that a normal IUP is present.
identification of a gestational sac within the endometrial cavity
The gestational sac grows about ___ per day.
1 mm
The yolk sac should be visible when the msd is …
greater than or equal to 13 mm.
This is when an egg is fertilized and implants but the embryo either never forms or stops forming early on.
blighted ovum (anembryonic gestation)
T/F? The MSD can be used to date a second trimester pregnancy.
FALSE, early first trimester pregnancy.
T/F? Crown rump length is best used prior to identification of MSD.
FALSE, MSD before CRL is visible.
MSD = AP + Long + Trans divided by ___.
3
Is the yolk sac in the chorionic cavity or the amniotic cavity?
chorionic
What is the first structure we see within the gestational sac?
the yolk sac
When is the yolk sac visible endovaginally?
By the 5th week, and ALWAYS by the time the MSD is 8 mm.
When is the yolk sac visible transabdominally?
By the 7th week, when the MSD is 20 mm.
When is a calcified yolk sac seen?
Only with a fetal demise
Visualization of the yolk sac predicts a viable pregnancy in ___% of cases.
90
The normal diameter of a yolk sac should never exceed…
5.6 mm
What is the most accurate measurement throughout pregnancy for dating?
crown rump length, accurate within 3-5 days
Embryonic growth is at the rate of ___ which is the same as the gastational sac growth rate.
1 mm per day
CRL (mm) + 42 =
GA (in days)
What is the first organ to function within the embyo?
heart
The embryonic heart starts beating at approx…
35 days.
By what week has the embryonic heart obtained its adult configuration?
8th
This is associted with bladder develoment and becomes the uracus and the median umbilical ligament.
allantois
Cysts can be seen in the umbilical cord between…
8-12 weeks
T/F? Umbilical cord cysts tend to be small and closer to the fetus.
true, mean size 5.2 mm
Name the three primary brain vesicles.
prosencephalon
mesencephalon
rhombencephalon
When do the brain vesicles develop?
Around the 6th week
There’s a cystic structure in the posterior aspect of the embryonic cranium. Do you panic?
Nope. It’s just the rhombencephalon dividing into two parts.
Bowel herniation should only be considered abnormal after…
14 weeks.
Nuchal translucency has been reported between…
10-14 weeks.
A nuchal translucency of 3 mm increases the risk of aneuploidy how many times?
4
Limb buds are recognizable during which week?
6th
The embryonic spine closes around the ___ week and the parallel echogenic lines can be seen at ___ weeks.
6th, 7-8 weeks
Embryonic fingers and toes are recognizable by which week?
11th