Skeletal muscle development and growth Flashcards
What are the primary germ layers?
- zygote
- blastula
- gastrula
From the gastrula, what are the layers?
- ectoderm (outer)
- mesoderm (middle)
- endoderm (internal)
- germ cells
What is the paraxial mesoderm?
- organised into somites
- somites give rise to axial skeleton and muscles, limb muscles and dermis
What is the intermediate mesoderm?
gives rise to urogenital system
What is the lateral mesoderm?
- heart (endo, epi, pericardium)
- blood
- endothelium (lining of blood vessels)
- wall of gut
- wall of respiratory tract
- lining of body cavites
Generally, what do you generate from the mesoderm?
muscle tissue
Explain the general process of somitogenesis:
- The paraxial mesoderm develops into the somitic mesoderm
- Somitic mesoderm has the layers of columnar cells, somitocoel and mesenchymal cells
- This develops into the somite with both sclerotome and dermomyotome
- Dermomyotome separates into dermatome and myotome
- The purpose of these is to make stem cells more committed to their tissue types
What does the myotome develop into?
epaxial and hypaxial muscles
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flexor and extensor muscles
what is the paraxial mesoderm also known as?
rostrocaudal strip
What is the sclerotome subdivided into?
rostral and caudal halves
The rostral and caudal halves are separated laterally by?
von Ebner’s fissure
These half somites of the sclerotome contribute to?
- single vertebral level body
- intervertebral disc
What is the dermatome?
- connective tissue underlying the epidermis
- begins as dorsal thickening
- spreads throughout body
What are the 2 parts of the myotome and what does it develop into?
body = epaxial and hypaxial muscles
limbs = flexor and extensor muscles
What do the epaxial muscles consist of?
vertebrae, ribs, base of skull