4.3 Muscle Embryology Flashcards
What are the 3 parts of the somite?
sclerotome, myotome, dermatome
What does the sclerotome form?
migrates around neural tube to form cartilaginous precursor of vertebrae
What does myotome form?
myoblasts differentiate into myotubes to form skeletal muscle
What does dermatome form?
dermis
limb buds come from elevations of ________ mesoderm
somatopleuric
skeletal muscles and vasculature develop from ________
somites
bones and tendons are derived from the _______ and have no somite contribution
lateral plate
craniocaudal development regulatory factors?
Hox genes, ZPA
ventral dorsal regulatory factors?
wnt-7a (dorsal) and engrailed-1 (ventral)
proximodistal regulatory factors?
apical ectodermal ridge and progress zone (PZ)
rotation of limb buds?
extend caudally –> ventral extension –> upper and lower rotation in opposite directions
more common in boys, walking on ankles
clubfoot
more common in girls, flat acetabulum
congenital hip dislocation
type of spina bifida with hairs over missing vertebral spinous process
occulta
type of spina bifida with meningomyelocele
cystica
type of spina bifida with neural tissue that has not formed at all
rachischisis
MYF5, back extensors innervated by dorsal rami
epimere
Myo-D, back flexors, trunk and extremities innervated by ventral rami
hypomere
in the vertebral column, ______ combine above and below to form each vertebra
somites
layers of the skin:
- epidermis forms from ______
- dermis froms from _____ + ______
- melanocytes from ______
ectoderm, dermatome + somites, neural crest
