Card Set Information
when is the embryonic period?
fertilization > 8th week
When is the fetal period?
9th week > birth
What is the most critical stage of development?
When does the initial appearanc eof all major organ systems occur?
when is the fetus most vulnerable to effects of drugs, radiation, and microbes?
Which trimester is the fetus nearly completed development of organ systems?
which trimester has the most rapid fetal growth?
What does the sperm penetrate during fertilization?
What does the sperm bind to during fertilization?
what happens when the sex cell's membranes fuse?
oocyte completes meiosis and divides
pronuclei form and fuses
results in a zygote
how many cells is in a zygote?
2 > 4 > 8
what is a morulla?
zygote with 16 cells in it
what happens in the first week of development?
blastocyst formation from the morula
---inner mass becomes embryoblast
--- outer wall is trophoblast
where does the zygote implant during the first week?
fundus or body of uterus
blastocyst attaches to endometrium
what happens during the second week of development?
trophoblast develops into 2 laters
embryoblast develops into bilaminar embryonic disk
what are the 2 layers of trophoblast(Chorion) in the second week?
what forms in the hypoblast?
what forms where the epiblast is?
What happens during the third week of development?
gastrulation produces trilaminar embyonic disc
what are the 3 primary germ layers that form during the third week of development?
what does ectoderm later become?
epidermis of skin, nervous system
where does endoderm later become?
epithelial linings of GI tract,
and many glands
Whhere does the mesoderm form?
between ectoderm and endoderm
what doest he mesoderm later become?
muscles, bones, C.T, peritoneum