Flashcards in Pregnancy Physiology Deck (84)
What days is the two cell stage present?
First 3 days of development
Solid mass of blastomere cells
When does a morula appear?
What day does the morula become a blastocyst?
What is the outer layer of the blastocyst consist of?
Placenta & fetal membranes
What is the inner layer of the blastocyst consist of?
Cell mass to become the embryo & fluid
What surrounds the blastocyst?
When does implantation occur?
What is the stem cell of the placenta?
Progenitor cytotrophoblast cell
2 Differentiation of Progenitor Cytotrophoblast Cells
Extravillous cytotrophoblast (inner)
Villous cytotrophoblast (outer)
Extravillous Cytotrophoblast (Inner) Cells
"Invasive" into decide & myometrium
"Invasive" into the spiral arteries (form uteroplacental arteries)
Form core of villi
Villous Cytotrophoblast (Outer) Cells
Forms placental villi with base of cytotrophoblast cells
Forms umbilical arteries & vein
Function of Villous Cytotrophoblast (Outer) Cells
Transport of gases
Nutrient & wastes
Synthesis of peptide & steroid hormones that influence placental, fetal, & maternal systems
Influence by progesterone & later with the invasion of trophoblasts
What forms the basal plate of the placenta?
Layer of trophoblast cells always separate the embryonic circulation from maternal blood & decidua
Define Nitabuch's Layer
Layer of fibrin between the boundary zone of compact endometrium & the cytotrophoblastic shell in the placenta
Functions of the Placenta
Interface between mom & baby
Prevents rejection of fetal allograft
Enables respiratory gas exchange
Eliminates fetal waste products
Secretes peptide & steroid hormones
Metabolic Functions of the Placenta
Removal of lactate
Function of Cholesterol Synthesis
Precursor for production of progesterone & estrogen
Waste product of placental metabolism
Placental Peptide Hormones
Human chorionic gonadotropin (hCG)
Human placental lactogen (hPL)
Placental corticotropin-releasing hormone (CRH)
Insulin-like growth factor (IGF)
Vascular endothelial growth factor (VEGF)
Placental growth factor
Function of Human Chorionic Gonadotropin (hCG)
Maintains corpus luteum production of progesterone until placenta takes over at 6-8 weeks
Regulates placental steroid production
Function of Human Placental Lactogen (hPL)
Antagonizes maternal secretion of insulin to increase fetal glucose supply
Function of Placental Corticotropin-Releasing Hormone (CRH)
Stimulates fetal ACTH resulting in fetal adrenal making DHEA-S as precursor to placental estrogen
Placental Steroid Hormones
Enzymes to degrade maternal glucocorticoids
Function of Progesterone
Maintains non-contractile uterus
Anti-inflammatory & immunosuppressive to protect fetus
Function of Estrogens
Stimulated by placental HCG
Maternal & fetal blood supply DHEAS
Enzymes to Degrade Maternal Glucocorticoids
Placenta regulates exposure of fetus to glucocorticoids
Regulating fetal organ development & maturation