Muscle embryology Flashcards
Draw and label a diagram of developing mesoderm
d
Name the 3 types of mesoderm in a developing embryo
Intermediate mesoderm, paraaxial mesoderm and lateral plate mesoderm
What does intermediate mesoderm go on to form
geniturinary system
What type of muscle does mesoderm form
mast muscles
Give an examples of some things formed by ectoderm
pupils and sweat glands
What does the paraxial mesoderm form
somites from cells moving at the primitive streak
What does the paraxial mesoderm cause
smooth mucle differentation due to the presence of serum reponse factor
What 2 layers does the lateral plate mesoderm split into
splanchic and somatic
Whatt is formed from the splanchic layer
smooth muscle
Define a somite
A block of paraxial mesoderm that gives rise to skeletal muscle
What structure influences the formation of somites
the notocord
how many pairs of somites are there
34
What does the number of pairs determine
the age of the embryo
What do somites do once they form
differentiate
What do cells in the ventral/media section differentiate into
sclerotome
What does sclerotome form
vertebrae and ribs
What does cells in the dorsal section form
dermomyotome
What does the dermomyotome form
myotome muscles and the dermis of the back
How does the notocord regulate somite differentiation
It produces sonic hedgehog and noggin which induce sclerotone formation
How does the neural tube and lateral plate regulate somite differentiation
WNT proteins (which are activationg) and BMP proteins (which are inhibitiing) combine to activate MYOD, creating a group of muscle cell precursors that express MYF5
How do myoblasts regulate muscle developement
Undergo cell division which i controlled by growth factors
What happens when the number of growth factors decrease
- Fibronectin is secreted
- Differentiation is mediated by myogenin
- Myoblasts stop dividing
What do myoblasts fuse to form
myotubes
How do MYOD and MYF5 regualte muscle development
- Can convert non muscle cells into muscle cells
- THey activate muscle specific genes, which enable differntiation of myogenic precursor cellss in dermatome to myoblasts
