I’d like to clarify something we talked about in our embryology lecture – it has to do with mesoderm and the muscles of the head.
On this slide, we talked about how mesoderm bunches up into little bumps adjacent to the developing neural tube:
The bumps adjacent to the developing brain are called somatomeres, and they develop into the muscles of the head and neck. The bumps adjacent to the developing spinal cord are called somites, and they develop into the muscles and bones of the rest of the body (including the muscles and bones of the back).
This slide talks about the fate of the three germ cell layers:I tried to summarize things a bit so there wouldn’t be so many separate things to remember – but in doing so, it looks like I made the paraxial mesoderm more confusing (not less!).
The correct derivations for the bones and muscles of the head and body are as follows:
- The bones of the head are derived from neural crest.
- The bones of the rest of the body (everything except the head) are derived from paraxial mesoderm.
- The muscles of the entire body (including the head and the rest of the body) are derived from paraxial mesoderm.
Let me know if you have questions!