Differentiation of Intra. Mesoderm; Somites Flashcards
1
Q
What are the 3 parts of the intraembryonic mesoderm?
A
- Paraxial - conic part closest to neural tube/notochord
- Intermediate - bulging part btwn parax and lat
- Lateral Plate - narrower lateral part
2
Q
What are the 3 layers of the somites of paraxial mesoderm (top to bottom) ?
And their general derivatives.
A
- Dermatome - all skin except epi
- Myotome - axial muscles
- Scleratome - bones of vertebral column
3
Q
From which mesoderm part do the somites develop?
When?
Where does it start?
At what rate?
A
Paraxial
beginning of 3rd week
starts cranially > caudally
about 3 pair/day
4
Q
What are the somites generally?
What genes express to form them?
A
paired cuboidal bodies on either side of the neural tube
Notch pathway genes + Hox genes
5
Q
What are the 6 categories of somites along the length of the embryo and how many are there of each?
A
- 4 Occipital - wake up to pee at 4 AM
- 8 Cervical - wake up for real at 8 AM
- 12 Thoracic - lunch at noon
- 5 Lumbar - get off work at 5
- 5 Sacral - have a drink at 5
- 8-10 Coccygeal - dinner between 8-10
6
Q
What forms from the dermatome?
A
7
Q
What is the name of the cavity which briefly forms in the somites?
A
myocoele
8
Q
A
