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35 Cards in this Set
- Front
- Back
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What is the placenta? |
Fusion between fetal (chorion) and maternal (endometrium) tissue for physiological exchange |
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What is the status of the uterine endometrium during implantation? |
Proliferative Secretory |
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What is the status of the embryo when implantation begins? |
Blastocyst |
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What part of the trophoblast is essential for implantation of the blastocyst? |
Syncytiotrophoblast |
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What happens on Day 9 after implantation? |
Uteroplacental circulation is established via lacunae |
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When is the embryo completely embedded? |
Day 12-14 |
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What is the chorionic plate? |
Chorion adjacent to the embryo |
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What is the cytotrophoblastic shell? |
Trophoblast adjacent to the decidua basalis |
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What maintains the corpus luteum during implantation? |
HcG until placenta can take over |
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What is the response of the endometrium to an implanting embryo? |
Decidual reaction Decidual tissues into three separate tissues--basal (source of new cells)
Compact and spongy |
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What are the REGIONS (not tissues) of the decidua? |
D Basalis (site of implantation) D capsularis (decidua over top of embryo) D parietalis (remainder of endometrium) |
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What is the chorion formed by and what does it equal? What does it make? |
Chorion forms from chorionic villi
Chorion=trophoblast +extra embryonic mesoderm |
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How do chorionic villi develop? |
Primary villi=extensions of cytotyrophoblast into syncytiotrophoblast
Secondary villi=aquire core of extraembryonic mesoderm
Tertiary villi=blood vessels in core |
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What are regions of the tertiary chorionic villi? |
Stem villi: central support of villous tree Intermediate villi: branches of stem villi Terminal villi: where exchange occurs
Central vessels=arterioles, venules and capillary loops (or together sinusoids) |
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What is the junctional zone? |
Where placenta must separate from the endometrium
Basal plate=functional zone of endometrium and the chorionic tissue; separates with placenta at birth
Placental base=basal zone of the endometrium in decidua basalis area; remains in uterus |
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What does the D capsularis become as development goes on? |
Chorion laeve (loses villi) |
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What does the D basalis become as development goes on? |
Retains villi, chorion frondosum |
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What does the placenta equal? |
Chorion frondosum and decidua basalis |
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During week 3-4, the blood vessels that connect the chorion with the embryo form in what? |
Connecting stalk (umbilical vessels!) |
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What does a codyleon contain? |
Hypertrophied tertiary villi located between 2 placental septa |
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What do intervillous spaces become in complete placenta? |
Arterio-venous anastomosis for maternal blood
Blood goes from endometrial arteries --> villi --> fetal circulation |
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What changes occur in the placental membrane (which separates maternal and fetal blood) after month 4? |
Cytotrophoblast gone Syncytiotrophoblast thins Decrease in size of chorionic villi |
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What does the initial placenta membrane contain? |
Syncytiotrophoblast Cytotrophoblast Basement membrane Extraembryonic mesoderm Capillary endothelium |
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What are the three major functions of the placenta? |
Mediates transport and metabolism of nutrients and wastes
Secretes essential proteins and hormones
Protects embryo from immunological attack |
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How do material cross the placental barrier? |
By diffusion, endocytosis, exocytosis |
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What does the placenta secrete? |
Peptide hormones Steroid hormones Placental proteins |
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How does the placenta help protect the embryo/fetus (i.e. why is it not rejected by the mom?) |
Three possibilities: --surface of syncytiotrophoblast has no paternal histocompatibility agents --maternal immune system is selectively suppressed --decidual reaction sets up a safe house for fetus |
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What do we have to make sure gets out of the mom during delivery? |
Chorion Carefully inspect codyledons at birth |
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What is placenta previa? |
Implantation too near to the cervix Won't undergo same reactions as if in uterus Placenta has premature detachment with hemorrhaging |
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What is placenta accreta? |
Implantation of egg into basal zone Too far down; incomplete delivery of placenta |
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Abruptio Placenta |
Detachment of the placenta resulting from hemorrhage into decidual basalis Decidual necrosis and placental infarcts result (i.e. fibrous tissue forms)
Can be from maternal malnutrition, smoking, hypertension, trauma or drug abuse |
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Hydatidiform Mole (Molar Pregnancy) |
Trophoblast development without an embryo Will have increased hCG levels into second month An example of genomic imprinting |
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What is a complete molar pregnancy? |
Only paternally derived DNA is present Malignancy risk |
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What is an incomplete molar pregnancy? |
Maternal and paternal DNA is present but genes not being expressed
Phenotype of any embryo present depends on maternal/paternal DNA ratio |
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What is Velamentous cord insertion? |
Umbilical cord attaches to chorion and amnion |
