Early Embryonic Development Flashcards
teratogen
any agent, or factor that can cause congenital anomalies in an embryo or fetus
multipotent
can develop into more than one cell type
more limited than pluripotent cells
adult stem cells
totipotent
can form all the cell types in a body, plus the placental cells
Embryonic cells within the first couple of cell divisions after fertilization are the only ones
pluripotent
can give rise to all of the cell types that make up the body
embryonic stem cells
unipotent
one stem cell has the capacity to differentiate into only one cell type
What is migration?
Why is it important?
movement of cells in particular directions to specific locations
development and maintenance of organism
- embryonic tissue formation
- wound healing
- immune responses
differentiation
unspecialized embryonic cell acquires features of a specialized cell i.e. heart, liver, or muscle cell
Characteristics of mesenchymal tissue.
Develops into…
lack of polarity causes loosely associated cells creating a large extracellular matrix
Develops into connective, lymphatic and circulatory tissue
What are the teratogenic influences on the 3 stages of development
Predifferentiation - Death of embryo
Organogenesis - Structural defects (embryonic period)
Fetal growth - Affects functional maturation
What is a zygote?
Where does it divide?
What are the resulting cells called?
fertilized egg cell
Divisions (cleavage) occur in uterine tube
resulting cells are called blastomeres
Morula
16 cells, ‘mulberry’
late morula has 32 cells
zona pellucida still intact
What are the two parts of the blastocyst, and what do they end up forming?
outer cell mass (trophoblast) - will form part of placental membranes
inner cell mass (embryoblast) - will form entire embryo
through a bilaminar disc of epiblast and hypoblast
zona pellucida is shed shortly
What is gastrulation?
single-layered blastula turns into trilaminar (“three-layered”) gastrula
primitive streak
invagination in epiblast layer
will establish bilateral symmetry and initiate germ layer formation
notocord
Signaling structure for neural tube formation
formed from group of cells migrating through primitive node and down midline ventral epiblast