Osteogenesis

Question 1

endocondral ossification

Answer 1

• long bones, vertebrae, pelvis, and parts of other bones
• cartilage template resembling a small version of the bone is used for a guide for bone deposition
• initial bone deposited is woven bone (non-lamellar)
• remodeling leads to formation of compact and spongy bone as needed

Question 2

steps of endochondral ossification

Answer 2

1. fetal hyaline cartilage model develops
2. chondrocyte hypertrophy, cartilage calcifies, and periosteal bone collar forms around diaphysis
3. death of hypertrophic chondrocytes, dead tissue is cleared channels for angiogenesis, osteoprogenitor cells follow invading blood vessels and differentiate into osteoblasts, primary ossification center forms in the diaphysis
4. secondary ossification center forms in the epiphysis, chondrocyte hypertrophy, calcification of cartilage and blood vessel growth in epiphysis
5. bone replaces cartilage except the articular cartilage and epiphyseal plates
6. epiphyseal plates ossify and form epihphyseal lines

Question 3

osteogenic cells in the perichondrium differentiate into….and synthesize….

Answer 3

-differentiate into osteoblasts and synthesize new bone de novo (no calcified cartilage template) forming the bone collar or periosteum

Question 4

regions of the epiphyseal growth plate from the secondary site of ossification to the primary site of ossification

Answer 4

• resting
• proliferating
• hypertrophic
• calcified

Question 5

type of growth in the epiphyseal growth plate

Answer 5

• appositional and interstitial

- this extends the growth plate upward

Question 6

chondrocyte death in the growth plate serves what purpose

Answer 6

-chrondrocyte death trails the region of proliferation, therefore it keeps the epiphyseal plate at a constant thickness

Question 7

as the epiphyseal plate grows and new cartilage is calcified, what does this do?

Answer 7

-promotes osteoblast attachment and bone deposition

Question 8

osteoid

Answer 8

• granic material of bone (collagen)

- this is before it becomes calcified and bone tissue is laid down

Question 9

interstitial lamellae

Answer 9

-this is the lamellae that surround individual haversian systems inside the bone

Question 10

intramembranouse ossification

Answer 10

• flat bones in cranium, facial bones and parts of other bones
• NO cartilage template
• condensed mesenchyme leads to de novo bone formation
• initial bone deposition is woven bone
• remodeling leads to formation of compact and spongy bone as needed