Bones Flashcards
What is the functions of Bone
Provides support
acts as a lever for effect movement
protection of internal organs
calcium storage
hemopoiesis
what are the cells of bone
osteoblasts , osteocytes and osteclasts
what is the organic extracellular matrix
collagen type 1 , proteoglycans and glyocporitens
what is the inorganic extracellular matrix
minerals - ca , na , mg , po4
what is osteoprogenitor cells derived from
mesenchyme
what is the location of osteoprogenitor cells
on the bone surface under the periosteum
what is the function of the osteoblasts
syntehsis the organic compoents of matrix
where is osteocytes found
found in cavities (lacuane) between layers lamellae of bone matrix
what is osteoclasts
giant cells
what is the function of the osteoclast
respoirtion and remodelling of bone tissue
what does the unmineralzied matric eventually become
mineralisex bone tissue
Bone Mineralisation - what does osteoblasts form
osteoid amd matrix vescile
bone minerlisation - what does osteoid form
type i collagen, glycoproteins and proteoglycans
bone minerlisation - what does matrix vesicles form
alkaline phosphatase
bone mineralisation - what does type i collagen, glycoproteins and proteoglycans cause
increase Ca2+ concentration
bone minerlisation - what does alkaline phosphatase increase
Increases PO4 concentration
bone mineralisation - what does increase in Ca2+ and PO4 concentration cause
formation of CaPO4 crystals
bone mineralisation - what does calcium phosphate crystal
attract water molecules and aggreate into the masses of hydroxyapatite crystals
what do osteoblasts also release
very small membrane enclosed matrix vesicles which contain alkaline phosphate and other enzymes
what are some osteoid components
osteocalcine, binds calcium ions with high affinity
what does osteocytes derived from
oasteoblasts
what are osteocytes not capable of
not capable of mitosis
what happens to the number of osteocytes with age
decrease with aging and can caclify as well
what are osteocytes canliculi
thin cytoplasmic process
what is the function canaliculi
transport materials to the adjacent osteocytes
what is osteclasts in respotions bays
osteocytes lie within depression or crytps in the matrix when undergoing resportion
what is cortical bone
dense areas without caities
make up the shaft / diapghysis
what is cancellous
numerous interconnecting cavities or a fine meshwork and occupies the epiphysis
what is periosteum
dense connective tissue sheath
what are the two layers of periosteum
inner cellular layer
what is the outer cellular layer
what is the inner cellular layer
osteoprogenitor cells
osteoblasts
what does endosteum line
large intnerla marrow cavities of bone
how many layers of endoesteum
single layer of connective tissue
what does endosteum contain
flattened osteoprogenitor cells and osteoblasts
what is a osteon
cortical bone has a compact arrangement of bone
where do the blood vessels that penetrate
through the periosteum into the compact bone to occupy the central canal of these osteon
what is the external circumferential lamellae
outermost arrangement of the lamellae
what is haverisan canal
lamellae circular pattern around the blood vessels occupy a canal
what is Walkmans canal
perforating vessels
how many canaliculi
10 chains via gap junctions
what is outer circumferential lamellae
outer layers of bone are organised in lamellae that run around the bone
what is woven bone (primary bone)
irregular arrangment of collagen fibres
lower mineral content
what is lamellar (secondary bone)
regular layered arrangement of collagen fibres
higher mineral content
what happens in compact bone bone remodelling
old oesteon are resorbs and produce new ones
what does resorption involve
osteoclasts remove old bone in tunnel like cavities
what are the cutting bone invaded by
osteoprogenitor cells and sourpting loops of blood cappliers which are derived from the endosteum or peirostem
what cuts lines in the tunnels
osteoblasts
how are osteoid serected
cylic manner
what does cutting bone form
concentric lemaule of bone with trapped osteocytes in between and will continue to lay don boney tissue in the space
what is cement lines
visible surrounding an osteon
where is cement lines found
where constant remodelling of bone prdocues these lines so
what does remodelling causes
new osteons to be laid down over old ones
what are the areas present between osteon
intersisital lamellae
cartilage vs bone - permeability
cartilage - permeable
bone - non preamble
cartilage vs bone ability
cartilage - deformable
bone - rigid
cartilage vs bone - growth
bone - apposition only
cartilage - appositional and intersitial
cartilage vs bone - cells nourishment
cartilage - cells nourished by diffusion through matrix
bone - cells within the bone must be nourished by blood vessels that pervade the matrix
