Physiology of Bone Flashcards
What is mainly found in the organic portion of the ECM in bone?
collagen
What organic component in the ECM of bone aids in hydroxyl apatite crystallization and binds calcium?
Osteonectin and osteocalcin
What organic components of the ECM of bone binds growth factors?
Proteoglycans
What organic components of the ECM in bone mediate osteoclast adhesion to bone surface (bind osteoclast integrins)
Sialoproteins, osteopontins, and thrombospondin
What are the main inorganic components of the ECM of bone?
inorganic hydroxyapatites or mineral salts, primarily calcium phosphate
What functions to pack tightly, contributing to the hardness and ability to resist compression?
the inorganic components
What is the function of osteogenic cells?
develop into osteoblasts
Where are osteogenic cells located?
in the deep layers of the periosteum and the marrow
What is the function of osteoblasts?
Bone formation
Where are osteoblasts found?
in growing portions of bone, including periosteum and endosteum
what is the function of osteocytes
maintain mineral concentration of matrix
where are osteocytes found?
entrapped in matrix
what is the function of osteoclasts?
bone resorption
where are osteoclasts found?
bone surfaces and site of old or injured bone matrix
Which bone cell type is cuboidal shaped?
osteoblast
which bone cell type directly regulates bone matrix synthesis and mineralization?
osteoblasts
How doe osteoblasts indirectly control bone resorption?
Through release of paracrine factors that regulate osteoclasts (RANKL/OPG)
What do osteoblasts eventually become?
osteocytes
Which bone cell can initiate apoptosis?
Osteoblasts
Which bone cell type is the terminally differentiated osteoblast?
Osteocytes
Where do osteocytes become trapped?
Within the newly deposited bone matrix
How do osteocytes respond to mechanical loading?
by releasing paracrine factors