Embryonic Dev. Flashcards
Starts in the union of germ cell and when does it end?
Fertilization ( cleavage)
Pattern of early mitotic division
Cleavage
T/f The size of cell changes in cleavage.
f.it does not only the number of cell increase
Formation of the priMary germ layers
Gastrulation
What are the types of eggs based on characteristics?
Isolecithal, mesolecIthal, telolecithal, centrolecithal
Sparse evenly distributed yolk
Isolecithal ( mammals)
Moderate yolk & unevenly distributed
. Mesolecithal (amphibians)
Dense yolk concentrated at one end
Telolecithal (birds & reptiles)
Yolk concentrated at the middle
Centrolecithal (fly)
Fertilization process in chronological order
Insemination- sperm capacitation-migration- acrosome reaction- forming of fertilization cone - penetration of sperm. - forming of fertilization membrane- formation of M&f pronuclei - union of m&f chromosomes
Several mitotic divisions and what are the cells called?
Cleavage ( blastomere)
A compact ball that have undergone mitotic division.
Morula
What junction is a result of cleavage
Tight junction
What junction forms the blastocoele
Gap junction
What rises off of the superficial layer of the morula?
Trophoblast/ trophoectoderm
What attaches the developing embryo to the uterine wall
Trophoblast
It is a fluid-filled intercellular space which coalesce into a single cavity
Blastocyst cavity/ blastocoele
When trophoblast, embryoblast, and blastocoele are present, what is it called?
Blastocyst
What are the three germ layers formed in gastrulation?
Ectoderm, mesoderm, endoderm
Inner cell mass develops into l. 2.in gastrulation?
Epiblast & hypoblast
The inner cell mass forms these layers inside the thropoblast.
Epiblast& hypoblast
The inner cell mass forms these layers inside the thropoblast.
Epiblast& hypoblast
The invagination of epiblast cells forms?
Primitive groove- primitive streak
It defines the longitudinal axis of the embryo and indicates the start of germ layer formation
Primitive streak
The proliferation of epiblast cells along the streak forms what?
Endoderm & mesoderm
The initial migrating cells join the hypoblast layer forming-?
Embryonic endoderm
The mesoderm divides into?
Paraxial, intermediate, lateral mesoderm
The mesoderm splits two layers bordering the coelom in lateral mesoderm
Somatic & splanchnic mesoderm
Attached to ectoderm
Somatic mesoderm
Joined to endoderm
Splanchnic mesoderm
The mesoderm that stream through the primitive streak
Primary mesenchyme
Organized cells having a distinct apical and basal surface
Epitheloid
The mesoderm that streams through the primitive streak
Primary mesenchyme
Temporary epithelioid turns to
Secondary mesenchyme
Notochord-induced transformation of ectoderm into nervous tissue
Neurulation
