EMBRYOGENESIS Flashcards
it is the formation of body structure and organs
embryogenesis
production of great variety of cell type and extracellular product is through?
- cell division
- cell differentiation
this results from cells expressing some genes and suppressing others within a common genome
cell differentiatiom
Time frame of the embryonic period
fertilization to earliest stage of organ devt.
time frame of fetal period
embryonic period to parturition
a series of mitotic division where large zygote id fractionated to many normal sized cells
cleavage
where does the cleavage begins?
zygote
term for the daughter cell resulting from cleavage
blastomere
T/F
blastomere are equal in size
False
unequal
A solid ball pf blastomeres within the ZP
Morula
how many blastomere does the morula have?
16-64
time of the 1st cleavage division (days)
1-5 days post ovulation
time frame of subsequent division of the 1st cleavage division
once every 12 hours
how many blastomeres are needed for embryo production?
approx 3 inner blastomere
they have identical potential in dom. mammals
First 8 blastomere
what stage of blastomere is differentiated into inner and outer cells?
more than 8 blastomere stage
what are the three types of twinning?
- monozygotic
- dizygotic
- polar body twins
they have the same chromosome or genetic composition
monozygotic t
What are the mechanism of monozygotic twins
- separation of early blastomere (8 cell)
- separation of inner blastomere in a single morula
type of monozygotic twin according to sharing of placenta:
separate placenta
Dichorionic twins
type of monozygotic twin according to sharing of placenta:
share placenta
monochorionic
type of monozygotic twin according to sharing of placenta:
twin to twin tranfusion
complication twins
type of monozygotic twin according to sharing of placenta:
anomalies due to the separation in embryo
diplopagus/ conjoined/ siamese
this twinning is composed of 2 genetically diff ova that is fertilized by 2 genetically different sperm
Dizygotic
twinning where ovum and 2nd polar body are fertilized
polar body twins
they have same gene from mother but different genes from father
polar body twins
morula stage that forms gap junction
inner blastomere
morula stage that forms tight junction
outer blastomere
outer blastomere becomes?
trophoblast - chorion & amnion
outer blastomere leave the uterine tube at 16 cell stage during what days?
4-7 days post fertilization
how many cell stage during the 5-7 days post fertilization?
32 cell stage
when does the blastocyst start?
2nd week, when ZP ruptures
during this, embryo is suitable for implantation
blastulation or blastocyst
the term referred to the fluid filled cavity during blastocyst
blastocoele
this prevents free exchange of fluid between inside and outside of embryo
tight junction
this permit exchange of ion and small molecules between cells
gap junction
Classification of egg cells according to amount of yolk:
very small amount
microlecithal
Classification of egg cells according to amount of yolk:
moderate amount
mesolecithal
Classification of egg cells according to amount of yolk:
large amount
macrolecithal
Classification of egg cells according to distribution of yolk:
even and is holoblastic
isolecithal
Classification of egg cells according to distribution of yolk:
concentrated in one side and is meroblastic
telolecithal
pole with more yolk
vegetal pole
pole with less yolk
animal pole
