Quiz 3 Flashcards
(28 cards)
Oropharyngeal
Oral
Cloacal
Anal
Body folding starts in week
4
Cranial neuropore closes (day/stage)
Day 25, Stage 11
Caudal neuropore closes (day/stage)
Day 28, Stage 12
Which week is the herniation of intestines?
Weeks 5-6
Oriented cell divison
Cells divide vertically
Oriented cell migration
Cells migrate in one direction
Convergent extension
Group of 4 cells –> converge to from a line
3 methods of embryonic lengthening
1) Oriented cell division
2) Oriented cell migration
3) Convergent extension
Neuroectoderm
- Induced from surface ectoderm by notochord
- begins as neural plate
Notochord: endo, meso or ectoderm?
Mesoderm
Neurulation steps
1) induction of neural plate folding
2) folds begint o converge
3) fusion of neural folds
4) NCC undergo EMT to ectomesenchyme
5) Cranial neuropore closes day 25
6) Caudal neuropore closes day 28
NCC
- arise from NCC
- dorsal migration: NCC reenter ectoderm via foles in basal lamina to form melanocytes
- ventral migration: become peripheral ganglia via anterior half of each somite
Surface ectoderm
completely surrounds embryo, becomes skin
Stomoderm
Mouth: Meets endoderm to from oropharyngeal membrane (no mesoderm)
Proctoderm
Anus: Meets endoderm to form cloacal membrane (no mesoderm)
Paraxial Mesoderm
Condenses into somites, cranial to caudal
Somite differentiation tree
Somites
Dermamyotome, Sclerotome
Dermatome, Myotome, Sclerotome
Intermediate mesoderm
forms gonads and kidneys (temporarily connects lateral and paraxial mesoderm)
How are the mesodermic layers oriented?
Notochord –> Paraxial mesoderm –> intermediate mesoderm –> Lateral plate mesoderm (splits into somatic-upper and splanchnic-lower)
What do the later plate layers become?
Under MET to become mesothelia
somatic - body cavity lining
splanchnic - organ lining
Endoderm
Lines gut tube
Why does intestinal herniation occur?
Intestines elongate faster than gut tube expands, causing them to herniate through umbilical ring
