Physiology of Pregnancy Flashcards
What does fertilized ovum do?
Divides progressively and differentiates into blastocyst as it moves form fertilization in upper oviduct to site of implantation in the uterus
How many days after fertilization is blastocyst transported and to where?
3-5 days
Uterus
What happens at 5-8 days post transplantation?
Attaches to lining of uterus
What do inner cells of blastocyst develop into?
Embryo
Outer cells of blastocyst develop into?
Placenta
Outer cells of blastocyst are collectively called?
Trophoblast
Placenta is derived from what?
Trophoblast and decidual tissue
What do trophoblast cells differentiate into?
Multinucleate cells which invade decidua and break down capillaries to form cavities filled with maternal blood
What week of pregnancy are foetal HR and placenta functional by?
5th week of pregnancy
PO2 maternal is higher or lower than foetal?
Higher
Is the PO2 levels maternalLY and foetally similar to CO2?
No it follows a reversed gradient
What does fetal oxygenated blood blow to the fetus in?
Via umbilical vein
Maternal oxygen poor blood flows back into which vessels?
Uterine veins
Foetal oxygen supply is facilitated by what 3 factors?
- Fetal Hb has increased ability to carry O2
- There is a higher Hb conc in fetal blood, 50% more than in adults
- Bohr effect means fetal Hb can carry more oxygen in low PCO2 than in high
Placenta transport of nutrients and waste? (water)
Water diffuses into placenta along osmotic gradient
Exchange increased during pregnancy up to 35th week (3.5L a day)
What follows H20 in placental transport?
Electrolytes (Iron and Ca2+) only go mother to child so mum must have a lot
Fetus main source of energy?
Glucose (passes the placenta via simplified transport high to low conc)
What does hCG do?
Prevents involution of corpus luteum
Effect on male testes of fetus