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12 Cards in this Set
- Front
- Back
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Mesodermal Condensation (Cranial to Caudal) |
Cardiogenic mesoderm Pre- choral plate - important signalling centre for forebrain development - ingression through cranial part of primitive node Notochord - ingression through the primitive node - important signalling centre - no derivatives in adults Paraxial Mesoderm ( Somites) - Flanking g norochord - Mainly trunk, head mesichymes Intermediate mesoderm - Only in trunk - Lateral to paraxial mesoderm - Genital Lateral mesoderm - only in trunk - most lateral |
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Somitogenesis |
Cranio-caudal Reorganisation and segmentation of paraxial mesoderm |
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Somitogenesis process |
Starts @ day 18 w/ formation of somitomeres - Loose Condensation of paraxial mesoderm - - forms ~50 pairs Somitomeres condece to form Somites @ day 20 - Except 7 most cranial -》 Contribute to musculature of head and neck 4 somites @ day 21 3-4 pairs per day -》@ day 30 42-44 pairs |
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Somitomeres |
Loose Condensation of the paraxial mesoderm (50 pairs) |
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42-44 Somite pairs |
4 occipital pairs 8 cervical pairs 12 Thoracic Pairs 5 Lumbar Pairs 5 Sacral Somites 8-10 Coccygeal somites |
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Occipital Somites derivatives |
4 pairs Occipital part of skull Bones around Nose, eyes, inner ear Extrinsic ocular muscles Muscles of tongue Muscles of tongue |
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Cervical Somites derivatives |
8 pairs Occipital bone Cervical vertebrae and muscles Part of dermis Part of upper limb musculature |
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Thoracic Somites derivatives |
12 pairs Vertebrae Muscles and bones of thoracic wall Thoracic dermis Part of abdominal wall Part of upper limbs musculature |
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Lumbar Somites derivatives |
5 pairs Lumbar vertebrae Abdominal muscles Abdominal dermis Leg musculature |
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Sacral Somites derivatives |
5 pairs Sacrum Dermis Musculature |
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Coccygeal Somites derivatives |
8- 10 pairs (majority degenerate 3-5 final) Coccyx Dermis Musculature |
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3rd week of development |
Gastrulation - formation of primitive streak -Ingrission - 3 germ layers Mesoderm condensates into - Cardiogenic mesoderm - pre chordal plate - Notochord - Paraxial mesoderm - Intermediate mesoderm - Lateral mesoderm Somitogenesis - Formation of somitomeres - First 4 pairs of definitive somites |
