May- Bone Flashcards
what makes up the organic part of bone?
fibrous and ground substance
what types of inorganic materials are present in bone?
Ca, phosphorus abundant
Mg, Na, K, citrate, bicarbonates
what molecules are mainly responsible for the formation of the hydroxyapatite crystals?
Calcium and phospohorus
does bone contain blood vessels?
yes (it is essential for cell nutrition)
does the periosteum cover the articular surfaces of bones?
no
what cells does the outer layer of periosteum contain?
collagen fibers, fibroblasts, mesenchymal cells
what is in the inner layer of the periosteum?
osteoblasts, mesenchymal cells and some collagen fibers
how does the periosteum connect to the bone?
Sharpey’s fibers.
what layer contains reticular fibers and lines the marrow cavity?
endosteum
how are osteoblasts formed?
mesenchymal cells differentiate into osteoblasts
how are lacunae and canaliculi formed during intramembranous formation?
osteoblasts secrete osteoid which surround the osteoblast and their cytoplasmic processes.
what is it called when osteoid calcifies?
ossification
the continuous ossification process yields trabeculae. how do the trabeculae grow?
trabeculae form radially from the center of ossification
when trabeculae enlarge, approximate each other and trap blood vessels, what is formed?
compact bone
what allows for appositional growth of the bone?
periosteum
what is endochondral formation?
using a cartilage template (hyaline model) that is replaced by bone
what is formed when the perichondrium is transformed into a periosteum and osteoblasts lay down osteoid?
bone collar
calcification occurs when which cells start to hypertrophy and secrete a phosphatase?
chondrocytes
in what part of the shaft is the formation of primary center of ossification occuring?
diaphysis (center of the shaft)
where does formation of secondary center of ossification occur?
epiphyses (and continues in the radial direction until only a thin rim of cartilage remains)
what separates the epiphysis from the diaphysis?
the epiphyseal plate
after bone has replaced cartilage, what two areas still contain cartilage?
the articular ends and the epiphyseal plate
name the growth zones of the epiphyseal plate.
resting, proliferative, hypertrophy, calcification, retrogression, ossification (know these zones and how they grow)
how do phosphatases affect lacunae?
they calcify the rims of lacunae, which leads to death of chondrocytes
what leads to closure of the epiphyseal plate?
when interstitial growth ceases
does bone usually continue to grow in thickness?
it remains faily constant but diameter of bone and marrow cavity continue due to osteogenic activity
what types of bone lack lamellae and have collagen arranged in irregular fashion?
immature, primary and woven bone
what type of bone have collagen fibers arranged parallel to each other?
mature, secondary and lamellar
what contain a neurovascular bundle in the osteon?
central haversian canal
what is an osteon?
structural unit of bone
don inner and outer circumferential lamellae contain a haversian system?
nope
what interconnects haversian canals and has the same contents as haversian canals?
volkmann canals
what is the purpose of the volkman canals?
pathway for blood vessels from periosteum and endosteum to enter the haversian canals
during bone remodeling what cell is responsible for the resorption of bone?
osteoclasts
what grooves are formed when osteoclasts begin to erode bone?
Howship’s Lacunae
what is secreted to break down bone during osteolysis?
acid phosphatase and proteolytic enzymes
what step in fracture repair is there connective tissue (fibroblasts, blood, macrophages and fibers) filling the space
procallus
what is it called when connective tissue is replaced by hyaline cartilage?
temporary callus
what is it called when cartilage is replaced by immature bone?
callus
what replaces immature bone?
mature bone
what increases serum calcium by stimulating the formation of osteoclasts?
parathyroid hormone
what thyroid secretion lowers serum calcium by increasing osteoblastic activity?
calcitonin
what increases calcium and phosphate absorption in the intestines?
vitamin D
lack of vitamin D leads to what disease?
rickets and osteomalacea
what is important for production of collagen and necessary for proper bone formation?
vitamin C
what disease would you get from lack of vitamin C?
scurvy
why do we need growth hormone?
signals proper growth of epiphyseal plate
