Lecture 13: Extraembryonic Tissues & Placenta Flashcards
What are the amnion and yolk sac derivatives of?
Amnion: epiblast
Yolk sac: hypoblast
Name the extraembryonic tissues.
Amnion, Yolk sac, Chorion, & Allantoes
What do the chorion and allantois interface with?
Chorion: part of fetal maternal interface
Allantois: placenta via umbilical cord
What two things make up the fetal-maternal interface?
Placenta and Chorion
What are functions of the amnion?
Buffer against mechanical injury, Accommodate growth, Allow normal movements, & protect fetus from adhesions
High levels of alpha-fetoprotein are strong indicators of _____.
Neural tube defects
Creatinine or Lecithin-to-sphingomyelin ration can be used to determine what?
Fetal maturity based on maturity of lungs
What is hydramnios frequently associated with?
Esophageal atresia or anencephaly
What is oligohydramnios frequently associated with?
Renal agenesis
What occurs during phase I of amniotic fluid formation?
Diffusion of electrolytes through fetal ectoderm, maternal serum added, secretion by amniotic membrane
What occurs during phase II of amniotic fluid formation?
Fetal urine added & filtration for vessels associated with chorion leave
What is the turnover rate of amniotic fluid in the 3rd trimester and at term?
3rd trimester: every 3 hours
Term: 500 mL/hour
Folic acid and vitamins A, B12, and E may concentrate where?
Yolk sac
Where is the site of origin of primordial germ cells and the location of blood islands?
Yolk sac
What is histiotrophic nutrition?
Endocytosis of folic acid and vitamins A, B12, & E in the yolk sac