Physiology of Pregnancy and Fetus Flashcards
Acts as the “fetal gut, lung and kidney”
Placenta
What does the placenta do for the fetus?
- Supplies nutrients
- Exchanges CO2 and O2
- Regulates fluid and disposes of wastes
The placenta synthesizes _____ that affect maternal and fetal metabolism
Steroids, proteins and hormones
The placenta has a large surface area for exchange, however the mother and fetal components still remain _____
Separate
What is the functional unit of the placenta?
Chorionic villi
Chorionic villi ____ to increase surface area and room for exchange of material
Branch
What arteries from the maternal side are involved with the placenta?
Spiral arteries
Spiral arteries from the mother empty into what?
Intervillous space
What drain the intervillous space?
Maternal veins
What does slow filling of the intervillous space allow for?
Adequate time for exchange of nutrients
What arteries does the fetal blood flow have?
2 umbilical arteries
Fetal umbilical arteries carry what type of blood?
DEoxygenated
The fetus receives the O2 (oxygenated blood) and nutrients from what?
1 Umbilical vein
Fetal capillary network has ______ to allow for slower blood flow and greater exchange
Terminal dilations
Describe the partial pressures of oxygen of the mother and fetus
Mother’s partial pressures of oxygen are much HIGHER than the fetal partial pressures of oxygen
What does the partial pressure difference of oxygen between the mother and fetus allow for?
Diffusion of oxygen into the chorionic villi for the fetus!
Fetal hemoglobin has a slightly different structure than maternal hemoglobin. Why?
It binds the limited oxygen with a higher affinity
How is CO2 transferred from the fetus to the mother?
Fetal blood has a lower affinity for CO2 than maternal blood, thus it favors the transfer
What are 4 other transfer mechanisms that can also occur at the placenta?
- Passive diffusion
- Facilitated diffusion
- Primary and secondary active transport
- Receptor mediated endocytosis
What is transferred to the fetus at the placenta via facilitated diffusion?
Glucose
What is transferred to the fetus at the placenta via primary and secondary active transport?
AA, minerals and vitamins
What is transferred to the fetus at the placenta via receptor mediated endocytosis?
Large molecules - antibodies, insulin
hCG
Human Chorionic Gonadotropin
What produces hCG?
Syncytiotrophoblasts