Placental development

Question 1

Fetal components

Answer 1

Cytotrophoblasts: inner of chorionic villi, makes CELLS

Syncytiotrophoblasts: outer of chorionic villi, secrete hCG (structurally similar to LH), stimualtes corpus luteum to secrete progesterone during 1st trimester.

Question 2

Maternal component

Answer 2

Decidua basalis: derived from the endometrium, maternal blood in lacunae

Question 3

Umbilical cord

Answer 3

Umbilical arteries and veins: derived from allantois

Arteries (2): bring deoxygenated from internal iliac to placenta
Vein (1): brings oxygenated via ductus venous into IVC

Single umbilical artery: associated with congenital and chromosomal abnormalities

Question 4

Urachal duct

Answer 4

3rd week: yolk sac forms allantois, which extends into urogenital sinus. Allantois becomes urachus, a duct between bladder and yolk sac

Patent urachus: urine discharge from umbilicus
Vesicourachal diverticulum: outpouching of bladder

Question 5

Vitelline duct

Answer 5

7th week: obliteration of vitelline duct (omphalmo-mesenteric duct), which connects yolk sacs to midgut lumen

Vitelline fistula: meconium discharge from umbilicus
Meckel’s: partial closure, melena, periumbilical pain, and ulcer.