Bone and Joint Structure Flashcards
What cells are in charge of creating bone?
osteoblasts
What do osteoblasts connect with to form the bone fluid barrier?
osteocytes
What does the bone fluid barrier regulate?
minute-to-minute Ca flux
Where are osteocytes located?
in lacunae
What are osteoclasts?
bone removing cells
Where are osteoclasts located?
Howeship’s lacuna
What do osteoclasts attach to?
mineralized bone
How do osteoclasts resorb bone?
they secrete H+ to dissolve mineral and secrete metalloproteinases to break down the organic matrix
What type of collagen is the organic matrix made out of?
type 1 collagen
What is the purpose of type 1 collagen in the organic matrix?
it provides tensile strength and flexibility
What are the non-collagenous parts of the organic matrix?
various cytokines, adhesion molecules, and enzymes
What type of mineral is the initial deposition of mineral in bone?
amorphous calcium phosphate
What is hydroxyapatine?
crystalline calcium phosphate - the dominant mineral in mature bone
What part of bone stores calcium and phosphorus?
the mineral part
Identify this structure:
epiphysis
Identify this structure:
physis
Identify this structure:
metaphysis
Identify this structure:
Articular cartilage
Identify this structure:
diaphysis
Identify this structure:
cortical bone
Identify this structure:
trabecular bone
Identify this structure:
periostium
Identify these structures:
osteons
Identify this region:
periostium
Identify these structures:
Haversian Canals
Identify this structure:
osteocytes
Identify this structure:
osteoblasts
Identify this structure:
cartilage
Identify this structure:
osteoclast
What is endochondrial ossification?
when bone forms in and replaces a cartilage model
What is required for normal chondrocyte growth?
growth hormone, insulin-like growth factors, thyroxine, and vitamin D3 metabolites
How many centers of ossification are there and what are they called?
2 - primary and secondary
Where does intramembranous ossification occur?
within fibrous tissue
What does woven bone turn into?
lamellar bone
What is woven bone?
temporary ragged and rough bone that is rapidly produced at bone at sites of periosteal injury
What is lamellar bone?
dense, well organized sheets of bone
When is lamellar bone produced?
during normal bone growth and remodeling throughout life
How is does bone compression stimulate bone growth?
mineral is distorted which creates piezoelectric activity which stimulates bone growth
What are the layers of the joint capsule?
fibrous, loose fibrovascular, and synoviocyte
What are the types of synoviocytes?
type a and b
What are type a synoviocytes and what do they do?
they are macrophage-like cells that are phagocytic, produce cytokines and inflamatory mediators
What are type b synoviocytes and what do they do?
they are fibroblast-like cells that produce hyaluronic acid and lubricin which is added to synovial fluid
Which layer of the joint capsule does not have a basement membrane?
the synoviocyte layer
What is articular cartilage made up of?
chondrocytes, collagen matrix, proteoglycan/GAG matrix, and water
What is the life-span of chondrocytes?
they are long-lived cells
What is the function of chondrocytes?
they have the enzymes (matrix metalloproteinases) that are able to produce and degrade matrix
What type of collagen is articular cartilage made out of and what is the function?
type II and IX to provie tensile/structural strength
What is the proteoglycan/GAG matrix made up of?
core protein with chondroitin SO4 side chains, hyaluronic acid, and hydrated gel
What is synovial fluid made up of?
ultrafiltrate, hyaluronic acid, and glycoproteins
What is the purpose of synovial fluid?
it is boundary lubricant and serves as a nutritional source for chondrocytes
When does squeeze film lubrication come into play and how does it work?
during joing compression and release; compression on the cartilage squeezes fluid to the surface and opposing surfaces ride on fluid film. Release from compression and the fluid is sucked back into the cartilage
What is the function of the nutritional pump?
it pumps out wastes and pumps in nutrients in the joint
