The embryonic period Flashcards
what is gastrulation
process that establishes the three primary germ layers, forming a trilaminar embryonic disk
define chordoma
benign or malignant tumor that arises from remnants of the notochord (found either intracranially or in sacral regions)
what is hCG (human chorionic gonadotropin)
glycoprotein hormone that stimulates the production of progesterone by the corpus luteum
what is human placental Lactogen (hPL)
protein hormone that induces lipolysis, elevating free fatty acid levels in the mother (growth hormone of the fetus)
how is amniotic fluid reabsorbed?
swallowing, absorption through GI tract, or excess is passed into maternal blood
define neurulation
formation and closure of the neural tube
what does Hox (Homeobox complex) do?
controls the basic segmentation of the human embryo in a craniocaudal direction during the embryonic period
what are the 2 layers in the embryo
epiblast & hypoblast
what are the 2 layers in the trophoblast
syncytiotrophoblast & cytotrophoblast
what is the extra embryonic (XE) Mesoderm derived from
epiblast (& yolk sac)
where is the extra embryonic mesoderm found
between the inner lining of the cytotrophoblast and yolk sac
what kind of support does the XE mesoderm give
mechanical and trophic
what is the fetal contribution to the placenta
chorion
what can a pregnancy ultrasound done in the 1st trimester do:
confirm normal pregnancy determine the baby's age look for problems determine the baby's heart rate look for multiple pregnancies (i.e. twins)
what major events occur during the embryonic period
all major body systems develop 2D disk to 3D cylinder Folding of the embryo Craniocaudal folding-CNS Lateral Folding-amnion/body wall
what is gastrulation the beginning of
morphogenesis
what are the three germ layers
endoderm, mesoderm, ectoderm