Pregnancy Physiology Flashcards
What days is the two cell stage present?
First 3 days of development
Define Morula
Solid mass of blastomere cells
When does a morula appear?
Day 4
What day does the morula become a blastocyst?
Day 5
What is the outer layer of the blastocyst consist of?
Trophoblast
Placenta & fetal membranes
What is the inner layer of the blastocyst consist of?
Cell mass to become the embryo & fluid
What surrounds the blastocyst?
Zona pellucida
When does implantation occur?
Day 6-7
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
Dicidua
Influence by progesterone & later with the invasion of trophoblasts
What forms the basal plate of the placenta?
Decidual cells
Define Trophoblast
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
Extra brain Interface between mom & baby Prevents rejection of fetal allograft Enables respiratory gas exchange Transports nutrients Eliminates fetal waste products Secretes peptide & steroid hormones
Metabolic Functions of the Placenta
Glycogen synthesis
Cholesterol synthesis
Removal of lactate
Protein metabolism
Function of Cholesterol Synthesis
Precursor for production of progesterone & estrogen
Define Lactate
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
Progesterone
Estrogens
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
Placental Transfer/Transport
CO2 & O2 exchange Glucose Amino acid Fatty acids Immunoglobulin G Drugs
Function of Estrogen (Maternal Physiology)
Enlargement of uterus Breast enlargement & growth of ductal structure Enlargement of the external genitalia Relaxation of pelvic ligaments Affects fetal development
Function of Progesterone (Maternal Physiology)
Induces endometrial secretory cells to decidual cells
Contributes to development of the conceptus before implantation
Inhibits myometrial contractions
May be involved with immune tolerance of fetus
Influences breasts for lactation
Helps develop thick mucus plug
Changes cervix, vagina, & vulva to allow stretching for delivery
Ophthalmic Changes with Pregnancy
Cornea thickens Decrease in intraocular pressure Visual field changes or double vision (abnormal) Diabetic retinopathy Secondary retinal detachments