Lecture 14 Flashcards
The ______ skeleton is a continuous interaction between apical ectodermal ridge and limb bud mesoderm
limb
The ______ ______ is an inductive interaction between sclerotome and notochord or neural tube
vertebral column
The ____ interacts between preskeletal neural crest cells and information along migratory paths and interacts between areas of the brain and overlying mesenchyme
head
Describe the common bone/cartilage differentiation pathway
- mesenchyme is induced to enter common pathway
- production of N cadherins which promote mesenchymal cell condensation
- TGF-B stimulates synthesis of fibronectin and N-CAM
- aggregated state of mesenchymal cells is stabilized
Describe the membranous bone pathway
- requires transcription factors Runx-2 and Osx
- mesenchymal cells differentiate into osteoblasts
Describe the permanent cartilage pathway
- mesenchymal condensation forms chondroblasts
- sox-9 causes chondroblasts to secrete collagen II and cartilage matrix
- sox-9 is continually expressed in permanent cartilage
Describe the endochondral bone pathway
- Runx-2, ihh, and BMP-6 induce this cartilage to undergo hypertrophy
- hypertrophic cartilage cells secrete bone proteins and vascular endothelial growth factor
- invading blood vessels erode the hypertrophic cartilage and bring in osteoblasts to replace cartilage with bone
Where is the centrum derived from
ventral and medial parts of paired sclerotomes
Where do the neural arches arise from?
dorsal regions of sclerotomes
The proximal development of the costal processes/ribs depends on expression of myotonic myogenic factors, ____ and____
Myf-5 and Myf-6
Distal development of the costal processes/ribs depends on ____ signals from somotaopleural mesoderm
BMP
the sternum is derived from the _______
lateral plate mesoderm
Where does the clavicle arise from?
neural crest
What is the neurocranium?
part of skull that surrounds the brain
what is the viscerocranium?
surrounds oral cavity and pharynx
