bone formation etc. Flashcards
What common organic ions are reserved in our bones
Calcium and Phosphorous
What are the 4 purposes of the skeleton
- structure
- protection
- locomotion
- mineral reservoir
What are the 3 limitations of bones
- rigid
- hard/brittle
- unable to expand from within (limited growth potential as can only expand at exisiting surfaces)
What are the 2 kinds fo bone Matrix
- organic
- inorganic
what are the 3 types of bone cells
- osteocytes
- osteoblasts
- osteoclasts
What is “Woven Bone”
haphazard collagen that has formed and mineralized quickly (young growing animal, fracture repair), causing the collagen fibres to have a woven orientation
weak
What is Lamellar Bone
thin layers of osteoid within which collagen fibres belonging to each layer are parallel to eachother and fibres of another layer run in a different direction to the previous layer
stron and takes longer to develop
What is an osteon
a tunnel which carries blood vessels and nerves to supply the bone with nutrients and oxygen (inner anatomy of the bone changes)
primary and secondary (branch off of primary)
Label the following image of an osteon
- lacunae
- haversian canal
- lamellae
- interstitial lamellae
- cement line
- canaliculi
What are osteoblasts derived from
mesenchymal stem cells
what is the purpose of osteoblasts
2
- synthesize and secrete osteoid
- active in the mineralization process (help grow bone)
What are osteocytes derived from
osteoblasts
characterisitcs of osteocytes
4
- interconnected by dendritic processes (how cells talk)
- reside within the lacunae which are interconnected by canaliculi
- long lived
- maintain the matrix
What are some indetifiers of osteoclasts microscopically
they are large and have multiple nuclei
What is the purpose of an osteoclast
responsible for tunnelling through the bone in order to create osteons (secrete proteases to destroy organic matrix via demineralization)
derived from bone marrow
What are the cellular mechanisms of bone modeling and remodeling
3
- coordinated action of osteoclasts and osteoblasts
- bone excavated in cylindrical tunnel by osteoclasts
- bone replaced by osteoblasts which follow and form concentric lamellae of lamallar bone on walls to form a secondary osteon
What does bone modeling and remodeling facilitate?
- change in bone shape
- change in bone material
- repair of damaged bone
- release of mineral ions
what is a stress fracture
a sydrome involving localised bone injury associated with fatigue damage
micro fractures from wear and tear/over stress)
what is “stress” in the context stress fracture
force per unit area
what is “strain” in the context of stress fracture
% of elongation
too much force over time
what is a yield point in terms of stress fracture
point at which the structure will no longer return to its original shape
What is fatigue in the context of a stress fracture
the progressive decline in material properties
cyclical loading of quite intense loads may steadily weaken the bone
What is microdamage
3
- structural damage of various levels
- cell death
- vascualr disruption
what are joints
2
- flexible interfaces between bones
- smooth bearing surfaces
what kind of growth is cartilage capable of
interstitial
happens from the inside out
how is cartilage matrix different from bone
- differences in biochemistry, microstructure, metabolism and cell types
- avascular and aneural (get nutrients/oygen from surrounding structures)
What are the 3 types of cartilage
- hyaline/articular
- fibrocartilage
- elastic
what are some qualities of hyaline/articular joints
8
- precursors to bones in embryonic skeleton
- present inside bones
- on joint surfaces
- slippery and hydrated
- withstand and distributed laod
- actas as a shock absorber
- self maintaining
- avascular, aneural, and alymphatic
what is the predominant type of collagen found in articular/hyaline cartilage
type 2 collagen
what are some qualities of fibrocartilage
6
- very strong
- white
- specialised for areas requiring tough support/great tensile strength
- lines the surfaces of bony grooves
- contains more collagen that hyaline cartilage
- lacks perichondrium
what types(s) of collagen does fibrocartilage contain
type 1 and 2
what are some characteristics of elastic cartilage
4
- yellow
- found in the pinna, tubes, anywhere that require flexible support
- keeps tubes permanently open
- similar to hyalin but contains elastic bundles throughout matrix
what are the cells found in cartilage/what do they do
4
chondrocytes
- produce and maintain cartilage matrix
- low density
- obtain nutrition and O2 by diffusion from nearby structures
- secrete new matrix when embedded in matrix
where does connective tissue develope from
the embryonic mesenchymal tissue (stem cells)
what are the 5 different types of connective tissues
- loose fibrous connective tissue
- dense fibrous connective tissue
- hyaline cartilage
- bone tissue
- adipose tissue (fat)
what are the main amino acids in collagen
- glycine
- proline
- hydroxyproline
- hydroxylysine
composed of strong covalent bonds
collagen found in the skin, tendons, organs, mature scar tissue, artery walls, the cornea, endomysium, fibrocartilage, surrounding muscle fibres, organic part of the bones and teeth is what type?
type 1
collagen found in the hyaline cartilage and vitreous humour is what type of collagen
type 2
collagen found in reticular fibres (organ stroma) and granulation tissue is what type of collagen
type 3
collagen found in the basal lamina, eye lens, fitration system of the capillaries and glomerula is why type of collagen?
type 4
collagen found in the intestinal tissue and placenta is what type of collagen
type 5
what are qualities of synovial fluid
6
- clear
- slightly yellow
- fills the joint space
- provides nutrition
- lubrication
- ultrafilate of plasma
why is analysis of synovial fluid helpful
- can determine is there is evidence of disease (infection, osteoarthritis, immune mediated arthritis)
- intra-articular injection for diagnostic (joint block) and therapeutic purposes (intra-articular medication)
what are the qualities of normal synovial fluid
5
- clear/yellow
- not cloudy/turbid
- viscous (forms a string between fingers or from end of fingers)
- low cell count
- some neutrophils, lymphocytes and mononuclear cells OK
what are some qualities of abnormal synovial fluid
3
- yellow/red
- cloudy/turbid
- watery
- increased neutrophils (bacterial and fungal infections)
- incrreased eosinophils (autoimmune)
- total protien outside normal limits (10-20)
- ph more than 6.9
What is perichondrium
a dense layer of fibrous connective tissue that cover the surface of most cartilage types
not fibrocartilage
what is the function of the synovial membrane
- to produce synovial fluid
- clear debris from the joint
- provide nutrition (brings blood vessels close to the cartilage surface)
Highly vascularized
