The Apical Ectodermal Ridge

question 28

Multiple Choice

The apical ectodermal ridge

• A)forms at the proximal end of each limb bud.
• B)plays a role in differentiation and elongation of the limb.
• C)ossifies prior to formation of the hand and foot plates.
• D)must undergo apoptosis before the limb can develop.
• E)secretes mesoderm for muscle formation.

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Definitions:

Concentric Lamellae

Circular layers of bone matrix in osteons that surround a central canal, providing strength and support to bone.

Compact Bone

The dense, hard outer layer of bone that provides strength and support to the skeletal structure.

Osteocytes

Mature bone cells that maintain bone tissue by regulating mineral content and communicating with other bone cells.

Avascular

Referring to tissues or spaces within the body that lack blood vessels, and therefore receive limited blood supply.