Lecture 2 Flashcards
Mesoderm undergoes differentiation when?
During Neurulation
Paired somites form from what?
Epimere
Segmentation of somites proceeds in what direction?
Anterior to posterior (head to tail)
The stages of frog embryo development (in order) are:
Cleavage, Gastrulation, Neuralation& segmentation, and organogenesis
Cleavage produces what?
A blastula
Cells in the blastula are—
totipotent
Characteristics of gastrulation:
1) formation of blastopore
2) Cell migration/movement
3) Cell differentiation
At the end of gastrulation, the embryo is–
Triploblastic
Gastrulation produces—
the three primary germ layers
1) Endoderm
2) Mesoderm
3) Ectoderm
The Neural plate becomes what, and then what again?
The Neural fold, and then the Neurocoel
Somites form either side of the —
Neural tube
Throughout Organogenesis, what happens to the specificity of the cells?
They go from pluripotent gastrula cells to multipotent neurula cells, and finally become fully differentiated within each organ system
If all somatic cells have the same genes, why don’t they all do the same thing?
Not all the genes are active
Neural crest cells arose when?
Between Cephalachordata and Urochordata
Neural crest cells are—
Migratory
What are some derivatives of Neural Crest Cells?
Schwann cells, branchial cartilage cells, odontoblasts, dermis of the face, heart
What helps organize vertebrate head and nervous system?
Ectodermal placodes
Ectodermal placodes form what?
lateral line, cranial nerves, sensory epithelium of the olfactory system, lens of the eye
Where did a patterning inversion of the body plan take place
Before te protostomes and then again Following the Ambulacraria branch
the Spemann organizing center expresses what genes as the dorsal lip forms?
The Noggin gene (over expression causes extra-large head)
Morphogens do what?
Induce cell differentiation and migration
When does Dorsal-Ventral patterning begin?
At fertilization when sperm entry reorganizes cytoplasm
How are the animal and vegetal poles determined?
Beta-catenin protein accumulates on the dorsal side of the fertilized egg
Where does the dorsal lip form?
Opposite the site of the sperm entry
