1. Notogenesis, neurulation, somitogenesis

2. Notogenesis, neurulation, somitogenesis
The embryonic axial structures development :
primitive streak
notochord
neural tube
somites

3. 3 week development of primitive straek as crucial structure in transformation of bilaminar into trilaminar embryo

4. 1 week from zygote to beginning of implantation

5. Implantation beginning - 7ED
endometrium, LP
endometrium, epitel
syncytiotrofoblast
cytotrofoblast
dutina blastocysty

6. 2 week implantation continues Embryo is at bilaminar blastoderm stage
2 week implantation continues Embryo is at bilaminar blastoderm stage. By bilaminar blastoderm development the period of blastogenesis terminates and begins the period of embryogenesis.

7. Implantation completed ED14 .

8. 3 week development of bilaminar into trilaminar blastoderm/embryo consisting of 3 germ layers: ectoderm, mesoderm, endoderm

9. Epiblast and primitive streak formation

10. Mechanism of embryonic mesoderm and endoderm development

11. morphogenetic centre in mesoderm, endoderm and ectoderm development
Primitive streak
morphogenetic centre in mesoderm, endoderm and ectoderm development
regulate epiblast cells migration and differentiation, that invaginate in its axis
mechanism?
production of particular growth factor s/morphogenss
FGF8- fibroblast growth faktor
mechanism of its activity?
E-cadherin expression decrease in epiblast cells

12. 3 germ layers develop from EPIBLAST
ectoderm and endoderm are arranged as epithelium
CAM +
mesoderm is not arranget as epithelium, histologically it is connective tissue – primary mesenchyme
CAM -

13. Development of notochord / chorda dorsalis epiblast precursors , invaginating in Hensen´s primitive node, migrate toward the prechordal plate, - creating the cord-like cellular axial structure, s.c. notochord

14. Axial orientation establishment

15. Body axis cranio-caudal, dorso-ventral , right-left established during 3rd week

16. Cranio-caudal axis
Cell signaliling from the area of rostral/cranial end of embryo,
anterior visceral mesoderm, AVM
genes OTX2, LIM1, HESX1 and factor Cerebrus - determine the head end (before the primitive straek formation)
PP, primitive streak - factor Nodal, belongs to TGFb - transforming growth factor
Cell - signalling from primitive node and notochord, gen Brachyury – dorsal mesoderm formation in the middle and caudal part of embryo
X gene defect – longitudinal axis shortening – caudal dysgenesis /regression

17. Dorso-ventral axis
1) mesoderm ventralisation BMP – bone morphogenetic protein FGF8 – fibroblast growth factor – determine, what will differentiate in ventral mesoderm – kidneys, gonads, bloodm vessels 2) mesoderm dorsalisation – Noggin, Chordin, Follistatin block the BMP , that results in notochord and somites formation, neuroectoderm diffrenetiation from ectoderm, differentiation of notochord and paraxial mesoderm

18. Signalling molecules and transription factors in primitive streak

19. Firstly, cranial part/ head process of notochord is established
Firstly, cranial part/ head process of notochord is established. Caudal part is established by caudal morphogenetic system (caudal end of notochord, intensively proliferating, and ectoderm close to primitive node), followed by gradual primitive streak shortening .

20. Neural plate induction
mechanism: interaction of notochord with adjacent ectoderm

21. Noggin, Chordin, Follistatin, neural inductors, for ectoderm to neuroectoderm in the region of forebrain and midbrain
Hindbrain and spinal cord are induced by WNT and FGF expressed in the region of the caudal morphogenetic system.

22. Neural plate induction and neural tube dvelopment (interaction notochordu/adjacent ectoderm)
neural folds
neural groove
neural tube

23. Neural tube development by activity of caudal morphogenetic systém results formation of hindbrain and spinal cord
caudal morphogenetic centre – intensive proliferating caudal end of notochord
caudal end of notochord gets beneath the primitive streak/primitive groove, that becomes determined to neuroepithelium at that region
primitive streak shortening
neural plate lengthening
neurulutaion (plate to tube development)

24. Neuroporus anterior ED 25 Neuroporus posterior ED 28

25. Histogenesis of neural tube wall

26. Neuroepithelium differentiation

27. Neural crest formation and its derivates

28. Neural tube dvelopment and intraembryonic mesoderm differentiation

29. 4 week neural tube , somites

30. Somites, 42 – 44 pairs of paraxial mesoderm, 1st pair in occipiteal region, 20ED Segmentation: Notch, WNT, segmentational genes retinoic acid, FGF8, kraniocaudal gradient S