Fertilization and Implantation Flashcards
What is the first stage of embyrogenesis
cleavage
what does zygote produce during cleavage
morula
when does first cell division occur
36 hours after fertilization
what comes after morula
blastula
what does a trophoblast become
chorion
what is chorion
zygote contribution to placenta
what becomes the embryo
inner cell mass after formation of trophoblast
Embryogenesis steps
cleavage, morula, blastocyst, trophoblast, embryo
when does blastocyst implant in uterus
week after fertilization
what does blastocyst consist of
trophoblast and embryo
what is trophoblast
ring of cells on blastocyst surrounding a cavity
when is hCG essential for maintenance of endometrium
first trimester or three months until placenta develops
what is role of hCG
substitute for LH in maintaining corpus luteum
what is role of corpus luteum
maintain endometrium
amnion
fluid filled cavity containing embryo
yolk sac
first site of rbc synthesis in developing embryo
allantois
develops from embryonic gut and forms the blood vessels of the umbilical cord
function of umbilical cord
transport blood between embryo and placenta
amnion, yolk sac, and allantois come from where
inner cell mass of blastula
gastrulation
when the three primary germ layers become distinct
what are the three primary germ layers
ectoderm, mesoderm, and endoderm
Endoderm
inner layer
Ectoderm
outer layer
Mesoderm
develops from endoderm
blastopore gives rise to which structure
anus
The ectoderm forms which structures
entire nervous system, cornea and lens, epidermis, nasal, oral, and anal epithelium
endoderm forms which structures
gi tract epithelium, liver, pancreas, respiratory epithelium, urinary bladder, epithelial lining of urogenital organs and ducts
mesoderm structures
muscle, bone, and connective tissue. cardiovascular system, lymphatic system, kidneys, blood, ureters, gonads, reproductive ducts, dermis of skin
what comes after gastrulation
neuralation
neuralation
formation of nervous system
when does neuraltion occur
when ectoderm differentiates into neural plate
When are all major organ systems present
8 weeks embryo is now fetus
during which trimester are organs being formed
first trimester
