intro to bone Flashcards
What makes up the MSK system?
bone muscle and connective tissue
what makes up the connecive tissues
tendons ligaments and cartilage
what is the axial skeleton
skull vertebral column and ribcage
appendicular skeleton
: pectoral girdle, Upper and Lower Limbs, Pelvic girdle
name 5 function of skeleton
support (helps you stand protection of vital organs movements- work with muscles minreal storage- stores calcium and phosphate produces blood cell- bone marrow
endochondral ossification precoursor
cartilage precoursor from hyaline cartilage
where are the 2 ossification centres
primary in the middle of long bone
and secondary at the end
the gap inbetween in the epipyseal plate
what happens in endochondral ossification
In endochondral ossification, bone develops by replacing hyaline cartilage. Cartilage does not become bone. Instead, cartilage serves as a template to be completely replaced by new bone. Endochondral ossification takes much longer than intramembranous ossification. Bones at the base of the skull and long bones form via endochondral ossification.
what makes up bones
cells and matrix
what are the bone cells
Osteogenic Cell
Osteoblast
Osteocyte
Osteoclast
what is the precoursor of all the bone cells
osteogenic
what are osteogenic cells
bone stem cell
what are osteoblast
bone forming
secreate osteoid
catayle minrealsation of osteoid
what are osteoids
which is the unmineralized matrix composed of type I collagen and glycosaminoglycans (GAGs)
function of osteocyte
sense mechanical strain to direct osteoclast and osteoblast activity
how is it formed
mature bone cell
formed when an osteoblast becomes imbedded in its secreation
osteoclast function
bone breaking
dissolve and resorb bonr by phagocytosis
origin
bone marrow
where can you find osteogenic cells
– Deep layers of periosteum
find osteoblasts
– Growing portions of bone, including periosteum and endosteum
osteocytes
– Entrapped in Matrix
Osteoclasts
– Bone surfaces and at sites of old, injured or unneeded bone
what is teh bone matrix made up of
organic and inorganic components
what makes up organic component
type 1 collagen and ground substance
what makes up inorganic component
calcium hydroxyapatite
Osteocalcium Phosphate
what is the ground substance made if
Proteoglycans
Glycoproteins
Cytokine and Growth Factors
what is the cycle of bones
from immature to mature
how are immature bone
First bone that is produced
Laid down in a ‘woven’ manner – relatively weak
how does it form mature bone
Mineralized and replaced by mature bone
describe strength and strcuture of mature bone
Mature bone:
Mineralized woven bone
Lamellar (layer) structure – relatively strong
what are the types of bone
Cortical, Cancellous
what is Cancellous and what is it suitable for
‘Spongy’ – honeycomb structure
Not suitable for weight baring
what is Cortical and suited fior
‘Compact’ – dense
Suitable for weight baring
where do you find cortical nd cancellous bone
flat bones of the skull
femur
what is osteons
unit of bone that makes up cortical bone
what are osteons made of
concentric ‘Lamellae’ around a central ‘Haversian Canal’
what is the haversian canal /contain
contain blood vessels, nerves and lymphatics.
what is it made by
osteoblasts but become osteocytes as they become trapped by their own minreal matrix
what connects 2 haversian systems together
volkmans canal
what orientation
transverse perforating canals
what is the structure of a long bone/adult
cortical bone on the outside
cancellous bone inside
primary ossification centre in centre
2 secondary ossification at each end
and a child femur at the end /strcutures
epiphysis
physis-> growing area
metaphysis
diaphysis –> long bone
what are 2 ways bones grow
interstital and appositional
what is interstitial growth
long bone growth
increasing in lengths
apposisstional growth
increasing in diameter
where does teh interistital growth occur
at the physis
Zone of elongation in long bone
how does appositional growth occur
deposition of bone beneath the periosteum to increase thickness
sequence
Ridges in periosteum create groove for periosteal blood vessel
Periosteal ridges fuse, forming an endosteum-lined tunnel
Osteoblasts in endosteum build new concentric lamellae inward toward center of tunnel, forming a new osteon
Bone grows outwards as osteoblasts in periosteum build new circumferential lamellae. Osteon formation repeats as new periosteal ridges fold over blood vessel.
Calcitonin controls sodium how
– stimulates calcium uptake into bone
three classifcation of bones
fibrous
cartilaginous
synovial
cartilage joints have
cartilage inbetween the joint
what is special in a synobial joint
synovial fluid secreated in synnovial cavity by a synovial membrane
function of Synovial fluid
reduce friction during movement
How are synovial joints stabilized?
bone surface
ligaments
muscle/tendons
ligaments in stability
Prevent excessive movement that could damage joint
More ligaments and tighter ligaments greater stability BUT less mobility
Less ligaments and laxer ligaments greater mobility BUT less stability
what is poor stability danger of
risk of dislocation
what is intramembranous ossification
During intramembranous ossification, compact and spongy bone develops directly from sheets of mesenchymal (undifferentiated) connective tissue. The flat bones of the face, most of the cranial bones, and the clavicles (collarbones) are formed via intramembranous ossification.
