Compact Bone
compact bone is arranged in
osteons
Where is spongy bone located?
interior of bones
Name one of the components of bone:
specialized cells
Describe Osteoprogrenitors function &
Where they are located
- stem cells (mesenchymal cells) that turn into osteoblasts
-Periosteum,endosteum, and vascular pathways
What is the periosteum?
outer membrane surrounding bone
What is the concentric lammellae
contains osteocytes in lacunae that are connected via canaliculi
Spongy bone is arranged in?
Trabeculae
Name one of the components that make up the bone:
Extracellular protein fibers
Where are Osteoblasts located
& how they perform osteogenesis by secreting what?
-periosteum,endosteum,vascular pathways
Secrete:
-osteoid
-bone sialoprotein: nucleus for apatite crystals of calcium phosphate, amyloid stimulate angiogenesis
-Osteocalcin: binds calcium to calcium phosphates for formation of apatite crystals
.calcification: calcium minerals build up in soft tissue and harden
.atherosclerosis: calcification of artery walls, may be caused by sialoprotein
What is the periosteum made out of and what type of CT?
fibrous outer layer (dense irregular CT)
What are perforating canals?
penetrate lamella and act as a channel for blood vessels to reach deeper osteons
Light to reduce weight
What Extracellular protein fiber is found in the bone?
collagen
How are osteocytes formed and what are their functions?
What may osteocytes relate in attempt to do?
What receptors are found on osteocytes?
- formed by osteoblasts (once encased in lacunae)
-connected via gap junctions in canaliculi
-osteocytes release nitric oxide which may:
signal osteoprogenitor to turn into osteoblasts AND prevent osteoclast formation
Receptors:
PTH receptors- cause osteocyte apoptosis
Estrogen receptors- help keep osteoblasts and osteocytes alive by blocking signals that cause apoptosis.
What fiber is found in Periosteum and what does it do?
Sharpey's perforating fibers extend into matrix
-continous with tendons and ligaments
What is circumferential lamellae?
are located on the outside of the compact bone.
What does the spongy bone make up?
the marrow cavity
Name one of the components that make up the bone.
Matrix
What are Osteoclasts function and how do they perform osteolysis?
- large cells with ruffled border
- perform osteolysis by:
-secreting H+ ions to acidify the matrix, which removes calcium phosphates from apatite crystals
-endocytosing calcium phosphates and releasing them into blood via interstitial fluid
what is another layer of the periosteum, and what does it contain?
cellular inner layer (osteoprogenitors, osteoblasts, osteoclasts)
where is compact bone located?
on the outside of the bone
Name the different marrow and what they store.
red marrow:
-hematopiesis
yellow marrow:
-adipose storage
What makes up the matrix, and which is the the organic matrix and inorganic matrix and what do they consist of?
Osteiod (organic matrix)
Minerals (calcium phosphates)
How is Osteoclastgogenesis performed?
proteins on fibroblasts and osteoblasts send signals to osteoclast precursors in the blood or bone marrow, telling them to turn into osteoclasts.
What does the Endosteum line, and what does it contain?
-Lines marrow cavity
-contains:
osteoprogenitors, osteoblasts, osteoclasts