Placenta Embryo Flashcards
Monozygotic Twins that separate 0-4days (~25%)
Either fused or separate placenta; both dichorionic diamniotic
Monozygotic Twins that separate 4-8days (~75%)
After morula stage; monochorionic diamniotic
Monozygotic Twins that separate 8-12days (
After blastocyst stage; monochorionic monoamniotic
Monozygotic Twins that separate >13 days
Monochorionic monoamniotic conjoined twins
Dizygotic twins
2 eggs, two sperm; more common than monozygotic
Primary site of nutrient and gas exchange between mother and fetus
Placenta
Inner layer of chorionic villi
Cytotrophoblast
Outer layer of chorionic villi; secretes hCG
Syncytiotrophoblast
hCG is structurally simmilar to what hormone
LH
Stimulates corpus luteum to secrete progesterone during first trimester
Syncytiotrophoblast
Derived from endometrium, maternal blood in lacunae
Decidua basalis
Normal components of umbilical cord
2 umbilical arteries, 1 umbilical vein, allantoic duct, Wharton jelly
Umbilical arteries and vein derivation
Allantois
Single umbilical Artery
congenital and chromosomal anomalies
Return deoxygenated blood from fetal internal iliac arteries to placenta
Umbilical arteries (2)
Supplies oxygenated blood from placenta to fetus; drains into IVC via liver or ductus venosus
Umbilical Vein
Duct between fetal bladder and yolk sac
Urachus (which is from allantois)
Urine discharge from belly button
Patent urachus
Partial failure of urachus to obliterate; fluid filled cavity lined with uroepithelium, between umbilicus and bladder.
Urachal cyst (can lead to infectio of adenocarcinoma)
outpouching of bladder
vesicourachal diverticulum
Time when vitelline duct is obliterated
7th week
Connects yolk sac to midgut lumen
Vitelline duct
Meconium discharge from umbilicus
Vitelline fistula
Partial closure of vitelline duct; atent part attached to ileum.
Meckel diverticulum
2 Tissue types associated with Meckel diverticulum
Ectopic gastric mucosa and or pancreatic tissue
