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Flashcards in Development of the Limbs Deck (13)
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1

What do the upper and lower limb buds form from?

somatopleuric lateral plate mesoderm

2

What are the two layers that each limb bud contains?

outer ecctodermal cap
inner mesodermal core

3

What layer of differentiated ectoderm induces differentiation throughout the limb?

Apical ectodermal ridge (AER)

4

What determines which limb segments will form?

The amount of time mesenchyme is under influence of AER

5

What layer subdivision gives rise to bones, tendons, lligaments and vasculature of the limb?

Lateral plate mesoderm

6

What layer subdivision gives rise to muscles of the limb?

Somitic mesoderm

7

Appendicular skeleton forms by endochondral ossification from condensations of _______?

lateral plate mesoderm

8

During the 5th week somitic mesoderm invades limb bud and forms a dorsal and ventral mass. What forms out of these masses?

Myoblasts -- which then form the muscles of the limbs

9

Which way does the upper limb rotate?

laterally

10

Which way does the lower limb rotate?

medially

11

How do the limb muscles get innervation?

Motor axons arising from the spinal cord enter the limb buds and grow into the dorsal and ventral muscle masses

12

Are the limbs innervated by dorsal or ventral primary rami?

Ventral rami

13

_________ enter the limb buds after the motor axons and use them for guidance

sensory axons