-
from two independent swellings
body and base and then completed -
Grow inferiorly,deep, in a vertical direction
Both sides of the developing tongue flip upward -
During 1st week
-Ovum is penetrated by the sperm and united, called fertilization -
During 1st week
46 chromosomes now. -
Zygote undergoes mitosis, or individual cell division.
Now known as morula, later is called blastocyst -
The blastocyst consists of a layer of peripheral cells, the trophoblast layer, and a small inner mass of cells, the embryoblast layer
-trophoblast- gives rise to important prenatal support tissue
- embryoblast layer gives rise to the embryo following the embryonic period -
certain processes or spatial and temporal events (patterning) occur which are key to development
-
induction, proliferation, differentiation, morphogenesis, maturation
- blastocyst will become an embryo with further development
- teeth and orofacial structures and other organs develop in an embryo -
one group of cells triggers the development of another group of cells, leading to specific developmental pathways.
-
following induction
-controlled levels of cellular growth leading to the expansion of tissues and organs
-appositional (size enlarges due to the addition of layers to the outside of a structure)
-interstitial (occurs from deep within a tissue or organ) -
change occurs in the embryonic cells, later becoming distinct structurally and functionally
-occurs at various rates
- cells, tissue types, organs, systems are affected -
tissue types and organs during embryologic period and continues later during the fetal period
-
primitive streak is a layer of symmetry caused by proliferation in the midline
- cells become mesoderm and endoderm -
Epiblast layer is now considered an ectoderm
-
Cephalic- head
Caudal- tail end -
CNS begins to develop
Neuroectoderm -
neural plate, neural groove, neural fold
-
Neural Crest Cells that migrate and disperse when the mesenchyme
-
into 38 paired cuboidal segments, forming the somites
-
4th week- face and neck begin to develop
primitive eyes, ears, nose, oral cavity, jaw areas -
beings during the 4th week
-
Mesoderm, ectoderm, endoderm
Developing brain, face, and heart -
5 facial processes
-
disintegration of oropharyngeal membrane
separates the stomodeum from primitive pharynx -
Frontalnasal process enlarges
mand. process- rise to maxillary process
mandibular process fuse at the center -
-
Middle nose, root of nose, tubercle of lip, philtrum -
5th week and completes at week 12
-
Formation of primary palate (5-6 week)
Formation of secondary palate (6-12 week)
Completion of the final palate (12th week) -
forms from tuberculum impar
-
copula swellings -
9 week-birth