DIT 1-3

Question 1

How are long bones formed? (axial, appendicular, and base of the skull)

Answer 1

Endochondral Ossification

Cartilage model of the bone made by chondrocytes

Question 2

Membranous Ossification forms what type of bones?

Answer 2

Calvarium, facial bones.

No cartilage step, woven bone formed directly–> lamellar bone

Question 3

What cell type builds bone?

Answer 3

Osteoblasts

Question 4

Osteoclasts perform what function and are differentiated from what type of cells

Answer 4

break down bone, from monocyte lineage

Osteoclasts are multinucleated (giant cells)

Question 5

What effect does estrogen have on bone?

Answer 5

Inhibits apoptosis of osteoblasts. induces apoptosis of osteoclasts
they protect bone

Question 6

FGFR3 mutation is associated with a disruption in what bone process?

Answer 6

Achondroplasia, disruption in endochondral ossification thus a disturbance in long bone formation while membranous ossification is spared. results big head small limbs.

Question 7

What does FGFR3 do? it is associated with what in parents?

Answer 7

FGFR3 inhibits chondrocyte proliferation, thus inhibits endochondral ossification.
High Paternal age (Austin)

Question 8

A deficiency of functioning carbonic anhydrase leads to what condition and why?

Answer 8

Osteopetrosis ‘rock like bone’ (marble bone dz)
Defective carbonic anhydrase II doesnt allow the osteoclast to create the proper acidic environment it needs to break down bone: thus osteoclasts cannot function.

Question 9

Why is pancytopenia seen with Osteopetrosis?

Answer 9

because bone takes over the medullary space, thus less marrow and less hematopoiesis

Question 10

Associated with acute back pain, loss of height, kyphosis, older age, post-menopausal women

Answer 10

Osteoperosis, –loss of spongy bone

vertabral crush syndrome

Question 11

Paget’s Disease

Answer 11

Increased osteoclast and osteoblast activity.
increase in hat size, hearing loss (auditory foramen narrowing)
High ALK