Development of Musculoskeletal Systems Flashcards
- Mesoderm accumulates on each side of notochord
- Transverse fissures divide the paraxial mesoderm into blocks progressing from rostral to caudal
- Each block is a somite
- Rostral to the notochord, mesenchyme forms less developed somites called ____
somitomeres
is a gelatinous substance with star shaped
mesenchymal cells
Mesenchyme
connective tissue fiber forming cells and the mature cells are fibrocytes
Fibroblast-
cartilage forming cells
Chondroblast-
Bone forming cells
Osteoblasts-
muscle forming cells
Myoblasts-
- During the ____ in domestic animals, the outlines of somites first become visible
- Differentiation of somites commences around ____
- By the ____, when somite formation is complete, those formed at an earlier stage have undergone further differentiation
third week of gestation
fourth week of gestation
fifth week of gestation
- Ventromedial part
- Forms most of the axial skeleton (vertebrae, ribs, and base of the skull)
Sclerotome
- Dorsolateral part
- Form dermis of the skin
Dermatome
- Middle
- Forms skeletal musculature
Myotome
- Like somites, but smaller and less distinctly organized.
- Develop rostral to the notochord in the head.
- Migrate into pharyngeal arches and form muscles of the jaw, face, pharynx, and larynx.
Somitomeres
Two further regions of the this have been recently postulated:
* Syndetome, from which the tendons rise
* Somite cells that will form the vascular walls of the aorta and the intervertebral blood vessels
somites
type of muscle
Paraxial mesoderm that forms somites
and in the rostral region of the head,
somitomeres
Skeletal muscle
type of muscle
Splanchnic mesoderm
Cardiac muscles and Smooth muscles
type of muscle
Splanchnic mesoderm
Smooth muscles
muscle formation
Myogenesis:
- Fibers : striated, tubular and multi nucleated
- Voluntary
- Usually attached to skeleton
Skeletal muscle
- Fibers : non-striated, spindle-shaped, and uninucleated.
- Involuntary
- Usually covering wall of internal organs.
Smooth muscle
- Fibers: striated, branched and uninucleated.
- Involuntary
- Only covering walls of the heart.
Cardiac muscle
*Which Division of the trunk muscles
Dorsomedial margin
Dorsal trunk muscles
Epaxial myotome
*Which Division of the trunk muscles
Dorsolateral margin
Forms the limb muscles and ventral trunk muscles (diaphragm and abdominal muscles)
Hypaxial muscle
Three distinct lineages generate the skeleton:
Somites
Lateral plate mesoderm
Cranial neural crest
*Three distinct lineages generate the skeleton:
Axial (vertebral) skeleton
Somites
*Three distinct lineages generate the skeleton:
Limb skeleton
Lateral plate mesoderm
*Three distinct lineages generate the skeleton:
Branchial arches
Craniofacial bones and cartilage
Cranial neural crest