Bone & Cartilage

Question 0

When is woven bone formed?

Answer 0

In response to injury. Can be laid down v quickly although the deposition of fibres is irregular.

Question 1

What is the composition of bone?

Answer 1

60% inorganic - HA
25% organic - collagen, glycoproteins, proteoglycans (GAGs)
15% water

Question 2

When is lamellar bone formed?

Answer 2

Normal bone formation. Laid down more slowly and the fibres are arranged parallel. Contains fewer osteocytes.

Question 3

What is endochondral ossification?

Answer 3

Growth of ‘long’ bones.
Cartilage precursors are laid down. Cartilage proliferation occurs at the epiphyses forming an initial cartilage skeleton. Cartilage is replaced with bone.

Question 4

What is intramembranous ossification?

Answer 4

Growth of ‘flat’ bones. Bone formed de novo in connective tissue. No cartilage precursor present.
e.g. whole skull except the base is formed this way

Question 5

What is achondroplasia?

Answer 5

Genetic defect of cartilage growth.
It impairs endochondiral bone growth and has no effect on intramembranous bone growth.
Proportions - large head, small body, small lower jaw (gives upper teeth a larger appearance)

Question 6

How does tooth loss affect the jaw?

Answer 6

Resorption of the alveolar process after tooth loss.