Skeletal Flashcards
Unspecialized stem cells derived from mesenchyme cells of the mesoderm
Osteoprogenitor cells
Bone building cells
Osteoblasts
Mature bone cells that develop from osteoblasts
Osteocytes
Cytoplasmic processes which penetrate the bony matrix
Canaliculi
Involved in bone resorption
Osteoclasts
Forms the external layer of all bones; makes up the bulk of long bones
Compact bone
Functional unit of compact bone
Osteon
Found at the expanded heads of long bones; fills most irregular bones
Spongy bone
An irregular latticework of thin columns of bones
Trabeculae
Contains a blood vessel involved in the common nutrition of the osteon
Haversian canal
Rings of calcified matrix that surrounds the Haversian canal
Concentric lamellae
Concentric layers that surround the central canal; formed by osteoblast
Interstitial lamellae
Direct conversion of mesenchymal tissue into bone
Intramembranous ossification
Growing cartilage is systematically replaced by bone to form the growing skeleton
Endochondral ossification
Called ‘armored fishes’ because they had so much dermal bone
Ostracoderms
Cartilage-replacement bone from sclerotome
Somatic endoskeleton
Associated with gill arches and derivatives, derived from neural crest cells
Visceral endoskeleton
Non-mesodermal source of bone development
Neural crest cells
Most primitive form of scales; found in sharks
Placoid scale
Found in gar; grow in size as the fish ages
Ganoid scale
Thin, circular scales covered by a thin layer of epidermis and mucus
Cycloid scale
Most advanced of all the scale forms; has tiny comb like protrusions on the posterior of the scale
Ctenoid scale
A bony structure that forms the head of the vertebrates
Cranial skeleton
