Lec1&2 Flashcards
embryonic disk?
inside morula, cells form two cavities and this is separated by embryonic disk
ectoderm vs. endoderm vs. mesoderm?
ectoderm– outside– neural plate (nerve system) and neural tube (brain and spinal cord) – “attracto-derm”
NS, epidermis, eyes, ears, nose, hair, nails, skin, glands, tooth enamel
endoderm– inside–GI tract
mesoderm– middle (happens later)– muscles, dermis, CT derivatives (bone, cartilage, blood, dentin, pulp, cementum, PDL)
embryoblast vs. trophoblast?
embryoblast– when traveling after multiple clevage
trophoblast– when implanted
trimesters?
1st- w1~w14
week 1
2 layered germ layers (endo/ecto)
week 2
gastrulation phase, third germ laye= meso
week 3* (really important)
- neuralation phase, neural crest
- notochord as mark of the time of neural crest cells
- neural crest cells from ectoderm and migrate lateral-ventral direction toward future face
when neural crest is established and what will it become?
- during week 3
* neural crest cells migrates into 5 facial processes during week 4
week 4
- neural crest cells migrates into 5 facial processes/premordia
1 frontal nasal process
2 maxillary process (bilateral)
2 mandibular process (bilateral)
- face, nasal cavities, and mouth are derived from neural crest cells
- dentofacial deformities are direct results of neural crest cell migration disruptions
where are maxillary and mandibular process derived?
first branchial arch (of 6 arches) that is called mandibular arch or phryngeal arch
facial bones, muscles of mastication, mockers cartilage, incus, malleuswhat is second branchial arch called?
why branchial arches are important?
- major formation of head and neck (esp. mandibular arch)
* major malformation of head and neck happens here
why is skin a dural organ?
- epidermis from ectoderm
* dermis form mesoderm
branchial arches and cranial nerves?
1st arch– CN5 trigeminal
2nd arch– CN7 faical
3rd arch– CN9 Glossopharnygeal
4th arch– CN10 vegus
week 5
nose, eyes, ears migrating into position
starting to look like a human
developing occurs fast
week 6
mandible begins ossification