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15 Cards in this Set
- Front
- Back
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Somitogenesis |
Cranio-caudal Reorganisation and segmentation of paraxial |
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Somitogenesis time frame |
First pairs appear @day 20 4 simites @ day 21 42-44 final pairs @ day 30 |
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Occipital somites derivatives |
4 pairs Occipital part of skull Bones around nose, eyes and inner ear Extrinsic ocular muscles Muscles of tongue |
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Cervical somite derivatives |
8 pairs Occipital bone Cervical vertebrae and muscles Part of dermis Part of upper arm musculature |
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Thoracic Somites derivatives |
12 pairs Vertebrae Part of upper arm musculature Thoracic Dermis Muscles and bones of thoracic wall Part of abdominal wall |
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Lumbar somite derivatives |
5 pairs Lumbar vertebrae Abdominal muscles and dermis Leg musculature |
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Sacral Somites derivatives |
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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Somite Differentiation |
2 populations Dorsal - remain epithelial cells - form Dermomyotome Ventero-medial - Mesenchymal cells- form Sclerotome - populate space around notochord and neural tube-》 form vertebrae and ribs Notochord will regress and disappear |
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Sclerotome |
Populate space around notochord and neural tube - form vertebrae and ribs |
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Dermomyotome 2 p derivatives |
Dorsal portion , epithelial cells Myotome: - cells migrate laterally to form distinct muscle masses -》 trigger the development of the motor innervation from the spinal cord - Epaxial (Dorsal) and Hypaxial (Ventero-lateral) muscles of trunk - some cells invades developing limbs-》 limb musculature Dermatome: Forms the dermis of the skin Sensory info. Reflects Somatic organisation |
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Myotome |
Derivative if Dermomyotome Group of muscles that a single spinal nerve innervates Cells from each myotome migrate laterally to form distinct muscle masses that will trigger the development of the motor innervation from the spinal cord.– Epaxial (dorsal) and hypaxial (ventrolateral) muscles of the trunk– Some cells also invade developing limbs to form limb musculature |
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Dermatome |
Derivative of Dermomyotome An area of skin a single spinal nerve innervates Forms the dermis of the skin |
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Epaxial muscles |
Dorsal Around vertebrae |
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Hypaxial |
Ventral to vertebrae |
