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Intra-Embryonic Mesoderm (General Embryology)
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- 3. Notochordal process Extension of primitive pitinto prenotochordal process Primitive streak Connecting stalk Allantois LS Dr. Sherif Fahmy
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- 6. Amniotic cavity Yolk sac Degeneratingendoderm and floor of notochordal canal Roof of notochordal canal LS Dr. Sherif Fahmy
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- 8. 4-Notochordal plate Notochordal plate (roofof the canal) which intercalate (fuse) to endodermal layer. TS Dr. Sherif Fahmy
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- 10. 5-Definitive Notochord TS Dr.Sherif Fahmy
- 11. Intra-embryonic Mesoderm • Itis formed from proliferating cells from sides of primitive node and streak. • It fills the space between ectoderm and endoderm except at buccopharyngeal membrane, cloacal membrane (fusion between ectoderm and endoderm caudal to primitive streak) and median region which is occupied by notochord. Dr. Sherif Fahmy
- 12. Primitive streak Primitive node andpit ectoderm Endoderm Intra-embryonic mesoderm Dr. Sherif Fahmy
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- 14. 17 th Day Dr.Sherif Fahmy
- 15. Differentiation of Intra-embryonic Mesoderm •Intra-embryonic mesoderm on each side of notochord, divides into: 1- Paraxial Mesoderm: on both sides of notochord. 2- Intermediate Mesoderm: Middle part of the mesoderm. 3- Lateral plate Mesoderm: Lateral part which communicates with that of the opposite side infront prochordal plate. Dr. Sherif Fahmy
- 16. Bucco-pharyngeal membrane Cloacal membrane Notochord Intermediate mesoderme Paraxial mesoderm Lateralplate mesoderm Dr. Sherif Fahmy
- 17. 1- Paraxial Mesoderm Dr.Sherif Fahmy
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- 19. NotochordSomites of Paraxial mesoderm Dr.Sherif Fahmy
- 20. 1-Paraxial Mesoderm • Itis the most medial mesoderm. • It is divided into cubical masses called somites (42 – 44 pairs). • Formation of somites starts At the 20th day by formation of one pair at cranial region. Then this followed by formation of 3 pairs/day till day 30 then the rate becomes slower to complete full number at the end 5th week. • Somites are classified into: 4 occipital, 8 cervical, 12 thoracic, 5 lumbar, 5 sacral and 8 – 10 coccygeal. Dr. Sherif Fahmy
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- 24. Fate (Organisation) ofSomites • 1- Sclerotome: It is ventro-medial part that form vertebral column and intervertebral discs. • 2- Dermo-myotome: It is the dorso- lateral part which subdivided into: A- Dermatome: Forms dermis of skin. B- Myotome: Forms skeletal muscles of trunk and limbs. Dr. Sherif Fahmy
- 25. Notochord Neural tube Somite Sclerotome Myotome Dermatome Neuraltube Vertebra Skeletal muscles Dermis Dermo-myotome Dr. Sherif Fahmy
- 26. Muscles of back Muscles of anterolateral aspectof body Muscles of limb Dorsal ramus of spinal nerve Ventral ramus of spinal nerve Dermo-myotomes of upper limb Dr. Sherif Fahmy
- 27. 2-Intermediate Mesoderm • Narrowstrip between paraxial and lateral plate mesoderm. • It is divided into many segments. • It forms uro-genital system. Dr. Sherif Fahmy
- 28. Lateral Plate Mesoderm •Flat plate of mesoderm between intermediate mesoderm and margin of embryonic disc. • It is continuous with that of other side infront prochordal plate. • Intra-embryonic coelom: It is formed from fused small cavities. This coelom forms serous membranes of the body (pericardium, pleura and peritoneum). • Lateral plate mesoderm is split by the coelom into: -Somatic mesoderm & Splanchnic mesoderm. Dr. Sherif Fahmy
- 29. Bucco-pharyngeal membrane Cloacal membrane Notochord Intermediate mesoderme Paraxial mesoderm Lateralplate mesoderm Dr. Sherif Fahmy
- 30. NotochordSomites of Paraxial mesoderm Intermediatemesoderm Intraembryonic coelom Pericardium Pleura Peritoneal canal Cardiogenic area Septum transversum Dr. Sherif Fahmy
- 31. Neural groove Amnion Somatic mesoderm Intraembryonic coelom Notochord Splanchnic mesoderm Paraaxial mesodermIntermediate mesoderm Lateralplate mesoderm T.S. Dr. Sherif Fahmy
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