Developmental structures Flashcards
What is the purpose of the placenta?
Primary site of nutrient and gas exchange between mother and fetus.
What is the fetal component of the placenta?
Cytotrophoblast and Syncytiotrophoblast
What is the cytotrophoblast?
Fetal component. Inner layer of chorionic villi. Cytotrophoblast makes Cells.
What is the Syncytiotrophoblast?
Outer layer of chorionic villi. Secretes hCG, which stimulates corpus luteum to secrete progesterone during first trimester.
- LACKS MHC-I expression! Lower chance of attack by maternal immune system.
What is the decidua basalis?
Maternal componenent of the placenta. Derived from endometrium. Maternal blood in lacunae.
What are the contents of the umbilical cord?
1 umbilical arteries, 1 umbilical vein.
What are the contents and pathway of the umbilical arteries?
Deoxygenated blood from fetal internal iliacs to placenta.
What are the contents and pathway of the umbilical vein?
Supplies oxygenated blood from placenta to fetus - drains into IVC via liver or ductus venosus.
Where are the umbilical arteries and vein derived from?
allantois
What is the cushioning around the vessels in the umbilical cord?
“Wharton jelly”
Where are the umbilical arteries and vein derived from?
Allantois
When does the yolk sac form the allantois?
3rd week
What is the allantois when it forms?
Outpouching of yolk sac connect to the urogenital sinus.
What does the allantois become?
When urogential sinus forms bladder, allantois is called the urachus, a duct between fetal bladder and yolk sac.
If there’s urine discharge from the umbilicus at birth, what happened?
Patent urachus
