Embryology_Skeleton-Muscles

ORGANIC AND FUNCTIONAL SYSTEMS

• Histology & Embryology: Cartilage, Bone, and Muscles

• Professors: Luca Tamagnone, Bianca Maria Scicchitano

Embryonal Origin of Skeleton and Muscles

• Mesodermal Origins:

  • Paraxial mesoderm

  • Intermediate mesoderm

  • Lateral plate mesoderm

  • Notochordal process

  • Somatic mesoderm

  • Splanchnic mesoderm

• Coelom development at Day 17 to Day 21

Mesoderm Differentiation

• Key Structures in Early Embryonic Development:

  • Somites

  • Formation of coelom

  • Mesenchymal tissue role in creating skeleton and muscles

Somite Development

• Components of Somite Formation:

  • Neurol tube, lateral mesoderm types (parietal and splanchnic)

  • Layers and differentiation into structures like dermamyotome and sclerotome

Somite Segmentation

• Formation Progression:

  • Neural folds and connection with structures like the pericardial bulge and cranial neuropore

  • Importance of somitomeres in arch formation

Differentiation of Somites

• Developmental Stages:

  • Neural groove's role in muscle and dermal development

  • Process identifying dermatome, myotome, and sclerotome

Musculoskeletal System

• Components:

  • Skull: Dentin, vertebrae, ribs, trunk muscles

  • Derived from different mesodermal layers (paraxial and lateral)

• Importance of neural crest cells in limb and trunk development

Myogenesis

• Skeletal Muscle Formation:

  • Myoblasts fusion leading to muscle fibers

  • Role of stem cell proliferation and differentiation in muscle growth

Ossification Processes

• Intramembranous and Endochondral Ossification:

  • Intramembranous: Formation of primary bone tissue from mesenchyme

  • Endochondral: Development through a cartilage model on secondary ossification centers

Joint Development

• Types of Joints:

  • Synovial joints - Examples: limb joints

  • Cartilaginous joints - Examples: ribs, pubic symphysis

  • Fibrous joints - Example: sutures in neurocranium

Spine Development Defects

• Examples:

  • Spina bifida occulta

  • Meningocele

  • Myelomeningocele

Limb Development

• Week-by-week progression in limb bud formation

  • Role of various signaling pathways (Hox, FGF)

  • Development of axial skeleton in limbs

Pharyngeal Arch Development

• Pharyngeal arches visible from the 4th-5th week

  • Mesodermal and ectodermal origins and structures, including pharyngeal clefts and pouches

Cartilage and Bone Development in the Head

• Role of occipital somites and somitomeres in muscle formation for head and neck structures

  • Derivative muscles and skeletal components from pharyngeal arches

Cleft Palate and Lip Development

• Processes leading to cleft lip/palate variations

  • Importance of the intermaxillary segment and palatogenesis

Neural Crest Contributions

• Role in skull, face, and neck structures development

  • Complex ossification processes and differentiation pathways

Summary of Muscle Innervation

• Overview of each pharyngeal arch's muscle and nerve supply

  • Specific muscles for mastication, facial expression, and pharyngeal functions

Conclusion

• Recap on the importance of mesoderm layers in embryonic development of skeletal and muscular systems.