Histo 6 bone histology Flashcards
Need to go over periosteal bone growth and bone remodeling
Where does hematopoiesis occur in adults?
in infants? where in bones does this occur?
Differences between compact and spongy bone?
Woven bone
Lamellar bone
What is bone made up of?
osteoprogenitor cells
osteoblasts
Osteocytes
Osteoclasts
Osteoclast differentiation
- Monocyte from bone marrow reaches area of bone formation and remodeling (M-CSF receptor on surface)
- Macrophage now. M-CSF ligand binds to M-CSF causes expression of RANK
- osteoblast expresses RANKL which binds to RANK this commits macrophage to osteoclastogenesis (osteoclast precursor)
- Resting nonfunctional osteoblast uncouples from osteoblast
- Maturation of osteoclasts is completed when the sealing zone and border appear via apha beta integrin
Osteoclast differentiation simpler
- Monocyte w/ M-CSF receptor
- Macrophage M-CSF ligand binds it (osteoblast)
- expresses RANK now
- Osteoblast has RANKL which bind RANK
- osteoclast precursor
- release from osteoblast (resting)
- sealing zone and ruffled border
- via integrin creates functional osteoclast
How are osteoclasts regulated?
osteoblasts has a RANKL decoy protein (osteoprotegerin) which blocks RANKL binding to RANK
this regulates number of active osteoclasts
(control differentiation not function)
Periosteum
does not cover articular surfaces
endosteum
Starting from osteon go outward with structures
What are the spaces in compact bone?
Intramembranous ossification
Endochondral ossification
(middle)
endochondral ossification
(head)
bone fracture repair
Achondroplasia
