Bone and Ossification

Question 1

What does each type of ossification produce?

Answer 1

Endochondral: Long Bone
Intramembranous: Flat Bone

Question 2

What type of bone formation uses a pre-cartilaginous pro-former?

Answer 2

Endochondral Ossification

Question 3

What are steps of Endochondral Ossification?

Answer 3

1) Creation of Hyaline Cartilage Pro-former
2) Bony collar established around diaphysis
3) Blood vessels penetrate bone collar and bring in osteoprogenitor cells
4) Primary centre of Ossification gets established (OB lay down Primary bone)
5) Secondary centre of ossification established in epiphyses
6) Cartilage level decreases and restricted just to bone plates

Question 4

What happens in intramembranous ossification? (3)

Answer 4

1) Bone directly deposited into mesenchymal tissue
2) Osteoblasts deposit isolated islands of bone until plate of primary bone created
3) Primary bone replaced with denser, lamellar secondary bone

Question 5

What is Woven (primary bone)?

Answer 5

Newly formed, poorly organised bone with calcium in amorphous form (Heavy and weak)

Question 6

What is Lamellar (Secondary bone)?

Answer 6

Organised collagen, calcium in crystalline (Hydroxyapatite) form, as bone lighter and stronger, replacing primary bone

Question 7

What is the difference between modelling and remodelling?

Answer 7

M: Happens during growth, with formation and resorption to sculpt adult shape
R: In adults: Removing and replaced old/damaged bone

Question 8

What is the role of Primary Osteons during rapid growth?

Answer 8

Primary osteons form to fill in holes left during rapid formation