Musculoskeletal System Flashcards
What are the three embryonic sources of the musculoskeletal system?
Paraxial mesoderm (somites), Lateral plate mesoderm (parietal and visceral), Neural crest cells
What are the three functional clusters of somites and what does each develop into?
Dermotone (dermis of skin), Myotome (epaxial and hypaxial muscles), Sclerotome (axial skeleton)
What is the innervation for epaxial and hypaxial muscles respectively?
Dorsal rami and ventral rami
What are the muscles progenitors of the first and second pharyngeal arches respectively responsible for?
Muscles of mastication (Arch I) and Muscles of Facial Expression (Arch II)
Distinguish epaxial from hypaxial muscles and name the only muscles in the smaller group
Epaxial muscles are dorsal to the horizontal septum of vertebrae, whereas hypaxial muscles are ventral to this line. The erector spinae and multifidus are the only epaxial muscles in humans
What tissue controls local patterns of muscle development?
The connective tissue in the area. Myoblasts migrate into the area and are given their instructions by this mesenchyme
Give the origin of the directive mesenchymal cells of the following regions: head, occipital and cervical, body wall and limbs
Head - Neural crest cell derivatives, Occipital and Cervical - Somatic Mesodermal derivatives, Body wall and Limbs - Lateral plate mesoderm derivatives
What developmental process allows muscles to cross adjacent vertebral bodies by shifting the vertebrae down relative to the surrounding tissue?
Resegmentation
Two general methods of bone formation and which type of bone they are used on
Intramembraneous (flat bones of cranial vault) and Intracartilagenous (long bones)
What structure exerts an important inductive influence in limb development?
The apical ectodermal ridge
