Development and Fracture Repair

Question 1

What are the two phases of skeletogenesis?

Answer 1

Phase 1: patterning, location, shape and size of future skeletal elements
Phase 2: cartilage and bone formation, differentiation of the specific skeletal types

Question 2

Where does the axial skeleton develop from?

Answer 2

craniofacial-neural crest and paraxial mesoderm

vertebrae/sternum/ribs: paraxial (somitic mesoderm)

Question 3

Where does the appendicular skeleton develop from?

Answer 3

lateral plate mesoderm

Question 4

What comes first, joint formation or cartilage formation?

Answer 4

joint

Question 5

What does the AER help form?

Answer 5

The apical ectodermal membrane is specialized epithelium that forms at the distal end of limb bud and controls proximal-distal development

Question 6

Describe the progress-zone model

Answer 6

cells directly underneath the AER are kept in an undifferentiated proliferative stage. Once they become far enough from the AER, they can start to differentiate

Question 7

What does the AER produce?

Answer 7

FGF

fibroblast growth factors

Question 8

What is the ZPA and what does it control?

Answer 8

zone of polarizing activity is an area of mesenchyme in the posterior limb bud