BIOL 3010 Lecture Notes - Myostatin, Myogenesis, Sonic Hedgehog
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Published on 29 Jan 2013
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Department
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Muscle
MUSCLE TYPES
Skeletal – syncitial
differential splicing different muscle fiber isoforms
Cardiac – mechanical coupling (intercalated disks)
Smooth – not syncitial, not striated; random actin-myosin arr.
MYOEPITHELIAL – iris dilator, mammary, salivary, sweat
glands; important for secretion
**from ectoderm associated w/ above organs**
DESCRIPTIVE EMBRYOLOGY
Mesoderm is initially a bilayer
PARAXIAL mesoderm axial skeleton
skeletal muscle
dermis
initially forms SOMITOMERE “whorls”
somitomeres (mesenchymal) SOMITES (epithelial)
first 7 remain somitomeres and form face/throat musc.
37 total somite pairs form in humans
ventral, LATERAL PLATE mesoderm splanchnopleuric
cardiac/smooth muscle
(dorsal, lateral plate somatopleuric mesoderm)
SOMITE DIFFERENTIATION – occurs anterior to posterior
ventral – SCLEROTOME axial skeleton, skull
medial – MYOTOME myogenic cells
1. ventral hypomere (lateral/ventral
body wall musculature)
2. dorsal epimere (spine muscles)
dorsal – DERMOTOME dermis
paraxial mesoderm
somitomere
somites
lateral plate
sclerotome
myotome, myogenic
dermotome