Lecture 4: Embryogenesis Flashcards
What field studies development between fertilization and birth?
embryology
What field studies embryonic and other developmental processes such as stem cell biology and regeneration?
developmental biology
What % of embryos are spontaneously aborted?
50%
what % of live born children have a birth defect?
3-6%
what % of births are premature in the USA? Is this higher or lower than the % of premature births in other developed countries?
~12%
higher
what are the two leading causes of infant mortality?
premature births
birth defects
Weeks _____ of human pregnancy are known as embryogenesis (also called organogenesis), when_______ are established
1-8
embryogenesis
What are organ primordia?
organs in earliest recognizable stage of development
The embryonic period is followed by the ______ of continued _______ and ______
fetal period
differentiation
growth
What are Carnegie Stages of embryogenesis based on? What are they not based on?
based on external features
not based on chronological age nor size
How many Carnegie stages are there?
23
What is postovulatory age refer to? what terms does it replace?
maturity of embryo - length of time since last ovulation before pregnancy
better than gestation, pregnancy, conception
In the ____ week of embryogenesis, the zygote undergoes division to become a _____ and then a _______
first
morula
blastocyst
What structure implants into the uterine wall?
blastocyst
The oocyte is fertilized in the ______ region of the ________
ampullary
uterine tube
what ploidy is the zygote?
diploid
how does the female anatomy help the sperm reach the oocyte?
muscular contractions of the uterus and uterine tube toward the ovary
without fertilization, the oocyte degenerates _____ after ovulation
24 hours
what kind of division do the oocyte and sperm undergo after fertilization?
mitotic
during cleavage mitotic divisions of embryogenesis, cells are known as _______
blastomeres
during cleavage mitotic divisions of embryogenesis, ______ segregates ______ fomr ______
compaction
inner cells
outer cells
____ days after fertilization, the ____-cell morula is formed
3 days
16 cell
How many hours post-fertilization... 2 cell stage 4 cell stage 16 cell stage late morula stage
2 cell stage - 30hrs
4 cell stage - 40hrs
16 cell stage - 3 days
late morula stage - 4 days
What stabilizes the cells during compaction of embryogenesis?
tight junctions between outer cells
seals off inner cells
