Osteochondrogenesis Flashcards
Bone histogenesis occurs by
intramembranous and endochondral bone formation (produce identical bones)
the combination of bone formation and resorbtion is
bone remodeling (slower in secondary compared to primary bone)
bone is a buffer for
calcium
osteoclasts form an _ and then after 2 weeks they undergo apoptosis and osteoblasts start formation of new osteon (remodeling)
erosion tunnel
when new bone is laid down on an eroded surface, a thin layer of _ is first produced
cementing substance (cementing or reversal line)
process for flat bone formation (skull, clavicle, etc.)
intramembranous bone formation
flat bone formation occurs in highly vascular
mesenchymal tissue
mesenchymal cells condense into _, differentiate into osteoblasts, and then begin secreting _
primary ossification centers
osteoid collagen
first bone formed is called
woven bone
osteoblasts trapped in matrix become osteocytes with calficiation; small spicules of developing bone unite to form
trabeculae
fusion of bony trabeculae produces _; blood vessels and other undifferentiated mesenchymal cells give rise to bone marrow
spongy bone
areas of mesenchymal tissue that don’t ossify differentiate into
periosteum and endosteum
woven bone initially formed from irregular osteoid collagen matrix will convert to _ in the outer layers; the inner layer remains as _
lamellar bone
spongy bone
process of long bone formation
endochondral bone formation
_ serves as a small model for the bone and as a scaffold for bone development (bone follows cartilage)
hyaline cartilage
endochondral bone formation has 2 stages
development of primary and secondary stages of ossification
primary center of ossificaiton develops at the _ of the cartilaginous model
midriff of the diaphysis
vascularization of perichondrium at the primary site of ossification transforms _ to _; they then differentiate into osteoblasts; perichondrium is now called periosteum
chondrogenic cells
osteoprogenitor cells
osteoblasts produce the _ on the surface of the cartilaginous model by _
subperiosteal bone collar
intramembranous bone formation
the chondrocytes at the primary center of ossification secrete _; the cartilage matrix begins to calcify
collagen X
osteoclasts create perforations in the bone collar to allow _ to enter the primitive marrow cavity in the C-model
periosteal buds (blood vessels, osteoprogenitor cells, and mesenchymal cells)
primitive marrow cavity formed by lacunae becoming confluent due to
calcified cartilage matrix inhibiting nutrient diffusion and hypertrophied chondrocytes dying
Bone matrix on the surface of the calcified cartilage forms a
calcified cartilage-calcified bone complex
calcified cartilage stains _ while calcified bone stains _
basophilic
acidophilic
_ begin to reabsorb the calcified cartilage-calcified bone complex enlarging the primitive marrow cavity
osteoclasts
secondary centers of ossification develop at _
epiphyses
when the epiphyses are filled with bone tissue, cartilage is found in 2 areas
articular surfaces and the epiphyseal plates
3 steps of secondary centers of ossification
1) articular cartilage remains (does not contribute to bone formation)
2) epiphyseal plates continue to grow (add new cartilage to epiphyseal end while being replaced at diaphyseal end)
3) diaphyseal and epiphyseal bone becomes continuous (this connects the two epiphyseal marrow caviti
5 epiphyseal plate zones
zone of reserve, proliferation, cell hypertrophy, calcification, and ossification (reabsorbtion)
zone of reserve
inactive chondrocytes
zone of proliferation
rapid mitotic divisions
zone of cell hypertrophy
chondrocytes are enlarged
zone of calcification
remnants of cartilage matrices become calcified and chondrocytes die
zone of ossification (reabsorbtion)
bone is made upon the calcified cartilage followed by the reabsorbtion of the calcified bone calcified cartilage complex
epiphysis enlarges by _ growth and _ replacement
cartilage
bone
parathyroid hormone related protein (PTH-RP) stimulates _ chondrocytes to divide but also inhibits _ chrondrocyte hypertrophy
reserve zone
proliferative zone
proliferation of _ from the periosteum and endosteum surrounding the fracture
osteoprogenitor cells
a _ forms both internally and externally at a fracture site
callus
during bone repair, endochondral bone formation replaces the cartilage with _ bone
primary (woven)
the irregularly arranged trabeculae of primary bone joins the ends of the fractured bone forming a _
bony callus
primary bone is eventually reabsorbed and replaced with
secondary lamellar bone
hairline fracture heal via
intramembranous bone formation (occurs at the periosteal surface)
immoveable joints composed of connective tissue, cartilage, or bone
synarthroses (unite the first rib to the sternum)
joints with slight movements commonly found in IV disks
amphiarthroses
permit maximum movement
diarthroses (also called synovial joints)
diarthroses unite long bones. they are surrounded by a 2-layered _, encloses and seals the articular cavity, which contains _ a colorless viscous fluid rich in _ and proteins
capsule
synovial fluid
hyaluronic acid
diathroses have a fibrous layer of dense connective tissue
external (fibrous) capsular layer
diarthroses internal (synovial) capsular layer has two types of cells
A and B
type A cells are
phagocytic with a well-developed Golgi complex and many lysosomes
Type B cells
resemble fibroblasts with a well developed rER; probably secrete synovial fluid (nutrients diffuse to hyaline cartilage from synovial fluid)
synovial tissue under the outer epithelial layers can consist primarily of
loose, dense irregular, or adipose tissue depending upon location
hereditary disease with abnormal osteoclast function (no remodeling occurs)
osteopetrosis
form of osteopetrosis
Albers-Schnoberg disease (marble bone disease)
loss of bone mass (primary trabecular); usually has normal rate of resorbtion but decreased bone formation
osteoporosis
rheumatoid arthritis starts as an inflammatory
reaction in synovial tissue
