Obstetric Flashcards
After fertilization the ovum turns into what cell, which contains 46 chromosomes
zygote
after a zygote goes through a division process called cleavage and then transitions into a which contains 16-32 cells
morula
on day 18-19 the morula exits the fallopian tubes into the uterine cavity and endometrial fluid penetrates the cell mass and creates what
blastocyst
what is the blastocyst inner cell mass as well as the outer shell of cells
-embryoblast (future embryo)
-trophoblast (future placenta)
what are the two layers of the trophoblast
-syncytiotrophoblast (outer)
-cytotrophoblast (inner) becomes the amnion
Which hormone is produced by the trophoblast
hCG (Human Chorionic Gonadotropin)
What days does the blastocyst attach to the endometrium
day 20-21
this is the anchor point for the blastocyst and begins the development of the primitive placenta
decidual basalis
Refers to the changes that occur in the endometrium in response to the implantation of a fertilized egg. The stromal cells of the endometrium enlarge, forming into decidual cells.
decidua reaction
if pregnancy takes place what two layers will begin to form at the syncytiotrophoblast to serve as the blood vessels to the placenta
chorionic villi to chorionic frondosum
a normal gestational sac is a rounded anechoic structure and seen in ultrasound at approximately what weeks LMP
5 weeks
early sonographic depiction of the GS (gestational sac) with an anechoic endometrial space and further out of the decidua capsularis. This is known as.
the double sac sign is a reliable indicator of a developing pregnancy in the very early stages
-initiation of placental development
-develops alimentary canal
-neuroplate develops into neurotube (future brain)
-fetal lungs beginning to develop but not yet active
Ovarian phase weeks 4-5
-primitive heart begins to beat
-primitive brain consists of : forebrain (prosencephalon), midbrain (mesencephalon), hindbrain (rhombencephalon)
embryonic phase weeks 6-10
-formation of anterior and lateral abdominal walls
-yolk sac fuses with vitelline duct to become umbilical cord
weeks 7-8
-mineralization of skeleton begins
-embryo becomes c-shaped with limb buds
-small bowel herniates at base of umbilical cord (developed outside of baby body before the abdominal walls closes on it) AKA gastroschisis
weeks 8
-functional fetal kidneys appear
-major organ system is established
-embryo demonstrates baby features
week 10
-organ development
-fetal intestinal activity begins
-fetal swallowing
fetal phase weeks 11-12
developed into nanotube brain and spinal cord
neuroplate
The innermost membrane of developing embryo
Amnion
Outermost layer of the developing embryo
chorion
Structure is responsible for production of amniotic fluid
-chorion frondosum
-chorionic and amniotic membrane
-skin, respiratory, and urinary tract
structures involved in reduction of amniotic fluid
-gastrointestinal system
-amniotic - chorionic interface
MSD (mean sac diameter)
(Length + Depth + Height)/3 = MSD
Most accurate to get GA; must be completed within the first 6 weeks
