What does GRAVIDA refer to?
Total number of pregnancies
What is a PRIMIGRAVIDA?
Pregnant for the first time
What is an EMBRYO?
Stage of organogenesis from 6 weeks to 10 weeks LMP; term used from 11 weeks to term
What is a FETUS?
The developing human after the embryonic stage
What does NULLIGRAVIDA mean?
Never been pregnant
What is PARITY?
Number of pregnancies carried to = 20+ weeks
What does PRIMIPARITY refer to?
First born
What is MULTPARITY?
Birth of 2 or more fetuses
What is MENARCHE?
Age of onset of menstruation
What is the VITELLINE DUCT?
Connects yolk sac to embryonic midgut
What are the trimesters of pregnancy?
1st trimester: LMP to 13 weeks;
2nd trimester: 14 weeks to 27 weeks;
3rd trimester: 28 weeks to term (40 weeks)
What could abnormal low levels of HCG indicate?
Ectopic pregnancy, incorrect dates, or non-viable pregnancy
What could abnormal high levels of HCG indicate?
Trophoblast disease, incorrect dates, or trisomy 21
INNER CELL MASS (ALSO TERMED EMBRYOBLAST) BECOMES THE
EMBRYO,
AMNION, CORD AND SECONDARY YOLK SAC
TROPHOBLAST
DIFFERENTIATES INTO 2 LAYERS
1.CYTOTROPHOBLAST - SINGLE CELL INNER LAYER FORMS
THE CHORION
2.SYNCYTIOTROPHOBLAST - OUTER MULTICELLED LAYER
WITH FINGER LIKE PROJECTIONS
*INVADES ENDOMETRIUM TO FORM LACUNAE SPACES
PRIMARY FUNCTION OF THE TROPHOBLAST IS THE PRODUCTION
OF HCG TO EXTEND THE LIFE OF THE CORPUS LUTEUM
IMPLANTATION THAT OCCURS WHERE THERE IS NO
ENDOMETRIAL LINING IS CALLED
AN ECTOPIC PREGNANCY (NOTE:
AN ECTOPIC PREGNANCY CAN STILL BE INTRAUTERINE)
1ST SONOGRAPHIC EVIDENCE OF AN
INTRAUTERINE PREGNANCY
GESTATIONAL SAC
Always able to image Gestational Sac (TA + EV)
EV - 2000 mIU/ml IRP
TA - 3600 mIU/ml IRP
explain the sequence of events from fertilization to implantation and what happens to the follicle at this time
begins with fertilization, which typically occurs in the ampulla of the fallopian tube, about 24 to 36 hours after ovulation.
A sperm penetrates the egg, forming a zygote with a complete set of chromosomes. After that, the zygote begins a series of rapid cell divisions known as cleavage while it travels down the fallopian tube toward the uterus.
Around 3 to 4 days after fertilization, the embryo becomes a morula, a solid ball of cells.
By about 5 to 6 days, it forms a blastocyst, which is a hollow ball of cells with an inner cell mass and an outer layer called the trophoblast.
Around day 5 or 6, the blastocyst reaches the uterus and begins to implant into the uterine lining. During this time, the follicle that released the egg turns into the corpus luteum, which secretes progesterone to support the early pregnancy and prepare the uterus for implantation.
BY DAY ?, (POST FERTILIZATION) THE INNER CELL MASS BECOMES THE
BILAMINAR EMBRYONIC DISK
day 11
what happens to the blastocyst during implantation, what new elements develop, make sure that you understand and can follow the division and development of the trophoblast, epiblast, hypoblast, umbilical vesicle, and amniotic cavity
During implantation, which occurs around six to seven days after fertilization, the blastocyst attaches to and then embeds itself into the lining of the uterus.
At this stage, the trophoblast, which is the outer layer of the blastocyst, plays a crucial role. The trophoblast differentiates into two layers: the cytotrophoblast and the syncytiotrophoblast. The syncytiotrophoblast is the part that invades the uterine lining, helping the blastocyst to securely implant and start forming the placenta.
Inside the blastocyst, the inner cell mass also differentiates into two layers, creating a bilaminar disk. These two layers are the epiblast and the hypoblast. The epiblast will eventually form the embryo, while the hypoblast contributes to the formation of some of the extraembryonic structures.
As implantation continues, a cavity forms within the epiblast called the amniotic cavity, which will eventually surround the developing embryo. At the same time, cells from the hypoblast line the blastocyst cavity and form what’s known as the primitive yolk sac or umbilical vesicle. This structure helps to nourish the early embryo before the placenta is fully formed.
In summary, during implantation, the trophoblast invades the uterine lining to support implantation and placenta formation. The inner cell mass forms the epiblast and hypoblast, creating the amniotic cavity from the epiblast and the umbilical vesicle from the hypoblast. This sets the stage for further development of the embryo and its supporting structures.
DECIDUA CAPSULARIS
CLOSES OVER
AND SURROUNDS THE BURROWING
BLASTOCYST SURROUNDS
BLASTOCYST (DEVELOPING EMBRYO).
EVENTUALLY FUSES WITH THE DECIDUA
PARIETALIS
DECIDUA PARIETALIS (OR VERA)
LINES THE REST OF THE ENDOMETRIAL
CAVITY WHICH IS NOT IMPLANTED BY
THE BLASTOCYST
DECIDUA BASALIS
THE AREA THAT THE
BLASTOCYST ATTACHES TO THE
UTERUS AND GOES ON TO CONTRIBUTE
TO THE MATERNAL PORTION OF THE
PLACENTA
