The Placenta Flashcards
Anatomic components of the placenta are seen from?
7th - 8th week gestation
Chorion, Amnion, Yolk sac and allantois constitute?
The embryonic or fetal membranes
The Chorion, Amnion, Yolk sac and allantois develop from?
The Zygote
Implantation of the blastocyst occurs ______days after fertilization
6 - 7
What are the two components of the placenta?
Maternal and fetal portion
The fetal portion of the placenta develops from?
The Chorion Frondosum
The maternal portion of the placenta develops from the _________ _______ formed at the endometrial surface?
decidua basalis
The major unit of the placenta is?
The Chorionic Villus
Within the chorionic villus are the?
Intervillous spaces
The maternal blood enters the ___________
Intervillous spaces
The maternal surface of the placenta is termed?
The Basal plate
The fetal surface of the placenta is termed?
The Chorionic plate
What are the functions of the placenta?
Protection
Nutrition
Respiration
Excretion
Fetal umbilical circulation originates with deoxygenated blood pumped by the ____________ through the __________ and into the ___________
fetal heart, Ductus arteriosus, descending Aorta
Umbilical arteries divide within the placenta into the multiple _______
tiny capillaries
Fetal placenta is anchored by the ____________ and __________
Cytotrophoblastic shell, anchoring villi
Cordal attachments are usually near the _____________
center of the placenta
As the embryo and membranes grow, the decidua capsularis is _______
stretched
Cord attaches at the margin of the placenta
Battledore placenta
Membranous insertion of the cord
Velamentous placenta
The umbilical cord has ______ arteries and _______ veins
2 arteries , 1 vein
The placenta normally implants on the _________, ________ or __________ wall of the uterus
anterior, fundal, posterior
Placenta covers the internal cervical os
Placenta previa
Placenta covers part of the internal cervical os
Partial placenta previa
Placenta does not cover the internal cervical os. Distance from the internal cervical os is at least 2 or <2cm
Low lying placenta
What are the fetal membranes?
Chorion, Amnion, Allantois, Yolk sac
The amnion fuses with the chorion and can no longer be seen on ultrasound as two separate membranes by_________
16 weeks
Separation beyond 16 weeks may be associated with_____________ or prior ____________
polyhydramnios, amniocentesis
Most of the amniotic fluid comes from the ____________
maternal blood
In the_______ trimester the fetus begins to excrete urine into the sac to fill the amniotic cavity
first
The amniotic cavity filled with urine serves as?
A protective buffer for the embryo and fetus
The amniotic cavity filled with urine provides what?
Provides room for fetal movements to occur
What are the functional endocrine units of the placenta?
Chorionic villi
The placenta has how many layers?
Two
The inner layer of the placenta is called?
Cytotrophoblast
The inner layer of the placenta ‘‘Cytotrophoblast’’ produces?
Neuropeptides
The outer layer of the placenta is called?
Syncytiotrophoblast
The outer layer of the placenta ‘‘Syncytiotrophoblast’’ produces?
- hCG
- Placental lactogen (hPL)
- Estrogen
- Progesteronen
What does hCG do?
It maintains the Corpus Luteum in early pregnancy
hCG peaks at?
8 - 10 weeks
Placental lactogen (hPL) is responsible for?
The promotion of lipolysis and an anti-insulin action that serves to direct nutrients to the fetus.
The fetal surface of the placenta (echogenic chorionic plate) is found?
At the junction with the amniotic fluid
The maternal portion of the placenta (basal plate) lies where?
At the junction of the myometrium and the substance of the placenta
The placenta is seen as early as__________
8 menstrual weeks
The placenta has midlevel gray appearance between _________
8 - 20 weeks
Diameter of the placenta is less than __________ in fetuses greater than ________
2 - 3cm , 23 weeks
After ___________ gestation the intraplacental sonolucencies and placental calcification may begin to appear.
20 weeks
An enlarged placenta may be associated with______________, ___________ and _____________
- Rh sensitization
- Gestational diabetes
- Congenital anomalies
Sonolucent regions may be seen within the placental substance in the center of the placental lobes known as____________
Placental lakes
This can mimic placental pathology and may distort the uterine contour
Braxton hicks contractions
What are the specific names to describe the point of origin of the placenta?
- Fundal anterior placenta
- Fundal posterior placenta
- Circumferential placenta
A succenturiate placenta should be considered when?
Both anterior and posterior placenta are identified and the placenta does not appear to communicate.
The position of the placenta appears to change due to the enlargement of the uterus during pregnancy
Placental migration
What doppler pattern is seen on the side of the placenta?
Low resistance Doppler pattern
