HISTO - bones Flashcards
found in periosteum and endosteum
gives rise to osteoblast
osteogenic cells
found in periosteum and endosteum
origin: osteogenic cells
function: secrete bone matrix and deposit ca= salts in it
fate: change to osteocytes
osteoblasts
branched cells
present in singly lacunae
branched run to canaliculi (to reach nearby blood vessels for nutrients)
origin: osteoblasts
function: maintain the bone matrix (by continuous deposition of nutrients)
osteocytes
clast =
destruct
large multinucleated cells on bony surface in Howship’s lacunae
striated or ruffled border (increase surface area)
cytoplasm rich in lysosomes (secretes acids to decalcify bone)
osteoclasts
origin: blood monocytes (monocytes fused together)
function: bone resorption (destruction of bone to release calcium)
osteoclasts
hard - it is calcified (calcium salts)
type 1 collagen fibers (pink color) acidophilic
forms bone lamellae and trabeculae
bone matrix
outer fibrous layer
inner oseogenic layer
periosteum
osteogenic layer only - dont need fibrous layer
fibrous layer is for protection from outside
endosteum - lining of bone marrow cavities
periosteum (OFL, IOL)
endosteum
bone lamellae
bone cells
compact bone
bone lamellae:
a. haversian systems (osteons)
b. ECL
c. ICL
d. Interstitial lamellae : between osteons
- longitudinal cylinders
- is formed of concentric bone lamellae (have osteocytes) and haversian canal (w/ blood vessels and nerves running in it)
- volkmann’s canal
haversian systems (osteons) - unit of compact bone
connect haversian canal together
(connect blood vessels and nerves of haversian systems
run obliquely or transversely
volkmann’s canal
- in flat bones and epiphysis of long bone
- periosteum
- endosteum
- irregular bone trabeculae (bone plates)
- many irregular bone marrow spaces (source of nutrients) (endosteum lines all these spaces
*bone cells - does not have haversian systems : no osteons
spongy (cancellous) bone
MACROSCOPIC:
- Compact bone (substantia compacta)
- Spongy or Cancellous bone (substantia spongiosa)
- solid continuous mass
Compact bone (substantia compacta)
- 3D lattice of branching bony spicules (trabeculae) occupied by bone marrow
Spongy or Cancellous bone (substantia spongiosa)
consists of thick walled hollow cylinder of compact bone with central marrow cavity (medullary cavity)occupied by the bone marrow.
Diaphysis (shaft)
- ends of long bones arising from separate ossification centers and separated from the diaphysis by the cartilagenous epiphyseal plates
Epiphysis
transition between the epiphyseal growth plates(growth zone)
Metaphysis
a layer of specialized CT with osteogenic property (ability to form new bones)
Periosteum
lines the marrow cavity of diaphysis and spongy bone with osteogenic property
Endosteum
mineralized interstitial substance deposited in lamellae 3-7 um thick
Bone matrix
uniformly spread throughout the interstitial spaces containing bone cell or osteocyte
Lacunae
