histology of Embryology 1 (2)

1. Dr Saima Ashraf

2. Development
Fertilization
Gastrulation

3. Organizer
Node
(Nodal,HNF3β)
Without HNF3 β embryo fails to gastrulate
properly lacking of fore &mid brain

4. DEVELOPMENT OF BODY AXIS
ANTERIOPOSTERIOR AXIS
Anterior visceral endoderm(AVE) expresses genes
including transcription factors called
OTXI LIMI HESXI Cerebrus
 HEAD FORMATION

5. DORSOVENTRAL AXIS
Ventralization of
mesoderm & ectoderm
BMP4(TGFβ)

6. DORSOVENTRAL AXIS
Goosecoid
Dorsalization of mesoderm in
cranial region
Down regulators of BMP4
Noggin Chordin Follistatin

7. DORSOVENTRAL AXIS
BrachuryT(gene)
Dorsalization of mesoderm in
mid and caudal region

8. Left Right sidedness
 Node and Primitive streak
 FGF8
 Nodal(lateral plate mesoderm after neural plate
induction) and Lefty II
PITX2

9. Left sidedness
 LeftyI (floor plate of the neural tube) and Sonic
hedge hog
 Repressors for the genes of left sidedness on the
right side
BrachyuryT
 Nodal ,LeftyI, LeftyII

10. RIGHT SIDEDNESS
NKX3.2/snail

11. MOLECULAR REGULATION OF
NEURULATION
BMP4 blocking
Dorsalization of Ectoderm, mesoderm in
cranial region
Down regulators of BMP4
Noggin Chordin Follistatin

12.  Caudal neural plate structures are induced by WNT-a
FGF

13. Fate Map