Anatomy and Histology of the Placenta Flashcards
What are the characteristics of a receptive uterus?
– Short irregular sparce microvilli
– Reduced uterine glycocalyx
– Large surface protrusions or uterodomes
– Flat cell borders and raised apices of uterine
luminal epithelial cells
– Well developed uterine glands
– Focal adhesion proteins well reorganized apically
What is implantation?
Blastocyst is embedded in endometrium
- completed by end of week 2
Note: utero-placental circulation is established
The trophoblast differentiates into?
- Cytotrophoblast - inner layer (mitotically active)
- Syncytiotrophoblast - outer mass (mitotically inactive)
- lacunae & secret human chorionic gonadotropin to maintain corpus luteum and endometrium
- invade endometrial epithelium
What separates the fetus from the endometrium?
placenta + fetal membranes
What is the placenta?
primary site of nutrient & gas exchange between mother & fetus
What are the 2 main components of the placenta?
- Fetal part - chorion (syncytiotrophoblast, cytotrophoblast, extraembryonic somatic mesoderm)
- Maternal part - derived from endometrium (decidua basalis)
What substances are transported between mother and child?
- From mother - nutrients, immunoglobulins & O2
2. From fetus - wastes: CO2 & urea
What are the functions of the placenta?
- Protection
- Metabolism (nutrition) - synthesis of glycogen
- Transport of gases and nutrients
- Excretion
- Hormone production - human chorionic gonadotropin
Describe the synctiotrophiblast?
Erodes stroma
Erodes maternal capillaries
Produces human chorionic gonadotrophin (hCG)
Describe the formation of the lacunae?
- As embryo disc forms, lacunae appear in syncytiotrphoblast
- Lacunae are filled with maternal blood + debris of eroded uterine glands
- Communications between eroded endometrium capillaries and lacunae form the primordial utero-placental circulation
