Bone Flashcards
Osteoblasts
Bone forming cells
- matrix synthesizing cell help build
Periosteum
Outer edge around compact bone
- outer - fibrous layer
- inner - osteogenic layer
Osteoclasts
Bone destroying cell and Absorb
- Can be bad
Osteogenic cells
Stem cells in periosteum and endosteum that boost osteoblasts
Endosteum
Delicate membrane on internal surfaces of bone
- contains osteoblasts / clasts
- covers within spongy, bone marrow between the trabeculae
(( RED MARROW CAVITY ADULTS))
Top of bones
- humerous
- femur
- trabecular cavity
Osteocytes - mature bone cells
- Keep things running in bone matrix
- Not building or breaking
Diploë
Spongy
Harversian system
- osteon - structural unit
Column like matrix
- run in different direction to prevent breaking ( collagen fibers )
- weight bearing
- lamellae
Central ( haversian ) canal
Blood vessels and nerves
Perforating ( volkmann ) canals
Right angled to central canal
- connects blood vessels and nerves of the periosteum and central canal
Lacunae
Small cavity that contains osteocytes
Canaliculi
Hair life canals that connect lacunae to each other and the central canal
Trabeculae
Lines of stress
- no osteons
- irregular arranged lamellae, osteocytes and Canaliculi
- capillaries in endosteum supply nutrients
Osteoid
Organic bone matrix secreted by osteoblasts
- ground substance
- collagen fibers
- strength n flexibility
Hydroxyapatites ( mineral salt )
65% bone mass
- calcium phosphate crystal
Resistance and hardness
Osteogenesis (ossification)
Bone tissue formation
- stages
• bone formation - 2nd month
• postnatal bone growth - until adult
• body remodeling n repair- life long
Two types of ossification
- intramembranous
Inside membrane
- fibrous
- flate bone
Two types ossification
- endocondral
Cartilage - bone forms by rebalancing hyaline
- from most skeleton
- most break down
Interstitial growth
Length of long bones
Appositional growth
Thickness n remodeling by osteoblasts & clast on surface
Epiphyseal
Resting zone -1- proliferation -2- hypertrophic -3- calcification -4- ossification Stymulated by growth hormones
Testosterone - male
Estrogens - female
Promote adolescent growth
Bone deposit
Occurs when bone is injured or needs strength
- needs protein, vitamins, calcium, phosphorus, magnesium,
Bone resorption
Osteoclasts secrete ( if need calcium )
- lysosomal enzymes ( digest )
- acids ( convert)
Control remodeling
- hormonal mechanisms
Maintain calcium
- homeostasis in blood
Remodeling
- mechanical and gravitational force
Demand = more
Comminuted
Bone fragments broke into 3 or more
Compression
Bone is crushed
Spiral
Break occurred when forced twist
Epiphyseal
Epiphysis (top) seperated from diaphysis ( middle ) along plate
Depressed
Broken bone is pressed inward
Green stick
Incomplete break, only one side of shaft breaks
Hematoma forms
Scab stops blood
- torn vessels hemorrhage
- clots form
- swollen, and hurts
Fibrocartilaginous
Phag cells clear debris
- osteoblasts form spongy
- fibroblast secretes fibers
- mass repair ( FBC - callus)
Bony callus
New trabeculae ( hard ) - continue until firm
Bone remodeling
- response to mechanical stressor
- final looks like old
Osteomalacia
- calcium salts don’t deposit
ADULT
Rickets
- bowed legs and other deformation
- no vitamin D
CHILD DISEASE
Osteoporosis
Back
- loss of bone mass - take more than put out
- spongy is weak
-
Pagets disease
crazy
- more breakage and building up then needed
- p bone has high ratio to spongy n reduce minerals
- unknown cause
-
Calcium used for :
- transmitting nerves
- muscles contraction
- blood caug ( stop bleeding)
- secretion of gland ad blood cells
- cell division
Wolffs law
A bone grows or remodels In response to forces and demands
Bone Fracture
1.) position
- Non-displaced - ends stay the same
- displaced - ends are different
Bone fracture
2.) completeness of break
- Complete - all the way broke
- incomplete - not broke all the way
Bone fracture
- 3.) orientation break of long axis of the bone
Linear - parellel
Transverse - perpendicular
Bone fracture
-4.) weather penetration occurs
Compound - open
Simple - closed