Week 1-2
When is Oocyte maturation arrested?
Prophase I
Where does the primitive streak form?
the posterior surface of the epiblast proper
What does the distal hindgut dilate to form?
cloaca
50-60% of congenital abnormalities are what?
idiopathic
What are the functions of the placenta?
protection, nutrition, excretion, respiration, hormone production
What are the two vulnerable periods of chromosomal abnormalities?
Gametogenesis and early cleavage of the embryo
What are the key ideas of notochord development?
primitive streak shrinks, notochord process grows
What is the origin of the central tendon of the diaphragm?
septum transversum
What do numerical changes result from?
non-disjunction(error in cell division)
What is the fetal membrane made of?
chorion, amnion, yolk sac, allantois
As the extraembryonic coelem forms, it separates the extraembryonic mesoderm into what two layers?
Extraembryonic somatic and extraembryonic splanchnic mesoderm
What are the primitive pit and groove a result of?
invagination of epiblastic tissue
The ectoderm covers the entire surface of the embryo except for the umbilical region. Why is this?
We have to have an exit and entrance for blood vessels
What is malformation? Could it be genetic?
morphological defect of an organ
Yes
What is happening when a mother has her "Water break"
amniochorionic membrane ruptures during labor and amniotic fluid escapes
Describe the formation of the amniotic cavity. What day?
By day 8 a small cavity appears in the epiblast as implantation proceeds. This is the primordium of the amniotic cavity
What forms blood islands?
mesenchymal cells called angioblast
Describe the horizontal folding of an embryo.
edges fuse cranially and caudally and zipper close towards the umbilicus leaving hole for umbilicus
Describe the critical development period.
stage at which the agent is introduced. Coincides with cell division and/or morphogenesis.
By 22-24 weeks, what happens to the decidua capsularis?
degenerates due to ischemia and smooth chorion then fuses with decidua parietalis except at the region of the birthing canal
What are the 3 phases of the female monthly cycle? Include the time frame of each(days).
Menstrual 1-5
Proliferative 5-14
Secretory 14-27
Name 5 processes that begin on day 18.(Chart)
neruoplate and groove
neurulation
somite development
intra-embryonic coelom
angiogenesis
Describe proposed methods for control of embryonic development.
dependent on genetic factors that increase cell migration through substances that may be definable, non-diffusable(ECM), or the result of cell-cell contacts
Structural birth defects do not always cause abnormal development. Why is this?
balanced translocation carriers
Placental septa attach towards the chorionic plate but never reach it. Why is this a good thing?
Allows free communication between intervillous spaces effectively separating fetal part of placenta into cotyledons