Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
21 Cards in this Set
- Front
- Back
|
DV axis formation |
Little is known ICM placement depends on sperm entry Ventral side hypoblast Dorsal is close to trophoblast |
|
|
AP axis formation |
Based on implantation side Ectoderm is proximal, epiblast is distal DVE Distal visceral endoderm |
|
|
AVE |
anterior visceral endoderm - extraembryonic structue BMP signals to induce wnt3 and nodal in epiblast |
|
|
Node |
Equivilent to hensens node anterior end of primitive streak Embryonic Nodal signal induces expression of DVE |
|
|
DVE induces AVE |
AVE promotes Wnt inhibitors - cerberus and dikkopf Nodal inhibitor lefty1 BMP inhibitors Prevents nodal activity in anterior FGF8 synthesized |
|
|
Anterior |
No nodal BMP, Wnts, FGFs are inhibited No retinoic acid |
|
|
Retinoic acid |
AP axis formation High in posterior Controls HOX genes |
|
|
How many genes do mamals have HOX genes on? |
4 |
|
|
HOX importance |
1. Specification of structures anterior to posterior 2. Paralogous groups (Hoxa-1, b-1, d-1) may be responsible for subsets of organs 3. Dominates over anterior - Posterior prevelence. Mutant means p dominates over a |
|
|
Notochordal plate |
Deposited by node, mesanchymal cells move to anterior, stop at prechordal plate and form a plate, attached to endoderm, folds inward, rod, detaches from endoderm, end location is mesoderm |
|
|
Functions of the notochord |
Induce neural tube
axis around which embryo develops axis to form vertebral column |
|
|
Ectoderm to CNS and Epidermis |
Epidermis becomes the outer epithelial layer |
|
|
Neural cells to neuroblasts |
1. Competence - exposed to right signals 2. Specification - received signal to become 3. Determination - will become neurons 4. Differentiation - neuroblasts |
|
|
Neural plate |
First sign of a nervous system Ectoderm thickens from signals be mesoderm --> enlongated columnar neural plate cells Extends along ap axis, thinning as it goes |
|
|
Neurulation |
Neural plate forms neural tube Neurula - embryo while this occurs Primary/secondary |
|
|
Primary neurulation |
1. Shaping and folding of neural plate 2. Elevation of folds 3. Folds bend to form neural groove, convergence 4. Closure, neural crest cells form, zipper/ several sites MHP medial hinge point, DLHP |
|
|
Expression of N and E cadherin |
Neural tube detaches due to switch in cadherin E - N Reduces binding affinity |
|
|
Neural tube closure |
B12 important Not sure May be effected by vitimin intake, area, season, fungal infections, pesticides |
|
|
Human neural tube closure, defects |
five locations Spina bifida - posterior failure or rupture Anencephaly - anterior Caniorachischisis - entire doesn't close |
|
|
Sites 1-5 |
1. Rhombencephalon - spinal junction 2. Prosencephalon - mesencephalon 3. Rostral 4. Caudal 5. L2 and S2 |
|
|
Secondary neurulation |
Occurs in tail region Condensation of mesechymal cells medullary cord - mesenchymal to epithelial condensing and bending |
