Endocrine function of osteoblasts
stimulation of PTH receptors causes release of osteoclast stimulating factor
–> bone resorption
In what manner does bone grow
appositional growth
Osteoblasts form what type of layer on bone
epitheloid layer
What are the recesses that house osteocytes called
lacunae
Are bones:
vascularized?
innervated?
yes
yes, especially periosteum
Cellular origins of osteoclasts
monocytes
Special microscopic characteristic of osteoclasts
multinucleated
Howship’s lacunae
depression where osteoclast is located
Hydroxyapatite crystals
calcium storage in bone
What type of crystals store calcium in bone
hydroxyapetite
What type of collagen is found in bone
type I
Glycoproteins in bone matrix function to what
bind different matrix components together
Cancellous/medullary bone
interior of bone, web-like network
Where does most bone turnover happen
medullary bone (more surface area)
Compact/cortical bone
dense, hard
Woven bone
“primary bone”
present up to 4 y/o and healing
Lamellar bone
“secondary bone”
replaces woven bone
mature bone
Diaphysis
area between epiphyseal plates
Metaphysis
transition from diaphysis to epiphysis
Epiphysis
distal end/head of bone
Epiphyseal plate
growth plate
Covering of epiphyseal plate
perichondrium
Where is periosteum found
only on diaphysis
What type of bone is found in the metaphysis
medullary
What type of cartilage is on the articular surfaces of bone
hyaline
What type of cartilage makes up epiphyseal plate in children
haline
What direction does bone mature
distal –> proximal
Sharpey’s fibers
anchor periosteum to bone
Where is the endosteum found
between marrow and matrix
What direction does the Halversian system run
longitudinally
What direction do the Volkmann’s Canals run
radially
What are interstitially lamellae
remnants of partially resorbed bone
What bones develop via intramembranous ossification
skull, mandible, maxilla, clavicle
What is the stem cell percursor for intramembranous ossification
embryonic
What bones develop via endochondral ossification
most
Where are primary and secondary ossification centers
primary: center of diaphysis
secondary: in epiphysis
3 phases of fracture repair
- hemorrhage
- soft callus
- hard callus
2 types of cells found in synovial capsule
fibroblasts
macrophages
What types of cells secrete synovial fluid
fibroblasts
Adult marrow color
yellow (may convert back to red when it needs to be)
Scurvy
ascorbate deficiency
Osteomalacia
prolonged adult deficiency of vitamin D
Rickets
vitamin D deficiency during childhood, can lead to bowed legs as a result of not being able to bear weight
Osteoporosis
osteoclast activity > osteoblast activity