Stages of Prenatal Development Flashcards
(142 cards)
human development begins with
fertilization
fertilization results in
new organism (single celled zygote)
what is a zygote
diploid cell with 22 autosome and 1 sex chromosome from EACH parent
total of 46 chromosomes
When does the zygote multiply its cells?
around 3 to 4 days post fertilization
what enters the uterine cavity
morula
these cells arrange as an inner and outer cell mass
blastocyst
what implants into the uterus
blastocyst
Can you have a pregnancy with no implantation?
no you have to have uterine implantation in order to have a pregnancy even though fertilization occurred
what must happen in order to have pregnancy?
the morula must enter the uterine cavity and implant
What sex chromosomes can mom and dad provide to zygote?
mom only an x because she is XX
dad either an x or a y because he is XY
what is a polar body
small haploid cell that is formed concomitantly as an egg during oogenesis but does not generally have the ability to be fertilized and degenerates
it cannot be fertilized
disappears around 12 hours after fertilization
1 of 2 small cells produced with the ovum (oogenesis) during meiosis and then degenerates
Morula =
Many cells
what is the blastulation process
where we are going from the morula to the blastocyst
inner and outer cell mass
blastocyst
outer cell mass becomes
trophoblast
trophoblast becomes
placenta
inner cell mass becomes
embryoblast
embryoblast becomes
gives rise to other body parts
what hours do we see 2 cell stage with polar body and blastomere
12-15 hours
at 12-15 hours after fertilization, what do we see
2 cell stage with polar body and blastomere
what hours do we see 4 cell stage
24-30 hours
what is the carnegie stages of development
system used by embryologists to describe the apparent maturity of embryosh
how is the carnegie stages determined
embryo assigned a stage from 1-23 based on external features
why is carnegie stages of development based on external features
the development of a fetus is very regular and we know what occurs when and what should look like during development and due to this we can find problems if there is one