Bone Growth and Remodelling

Question 1

Name the four types of bone cells?

Answer 1

Osteoprogenitor cells
Osteoblasts
Osteocytes
Osteoclasts

Question 2

Where are osteoclasts found and what is their function?

Answer 2

Found on sites of bone resorption

Function is to erode and remodel the bone

Question 3

What cells are osteoclasts derived from?

Answer 3

Blood monocytes

Question 4

What regulates osteoclastic activity?

Answer 4

Hormones act on osteocytes which regulate osteoclasts

Question 5

What substances to osteoclasts release?

Answer 5

H+ - acidic environment to solubilise the bone matrix
Cl-
Cathepsin K protease - degrades the protein and collagen

Question 6

What condition arises from ossification deficits?

Answer 6

Osteogenesis imperfecta (short stature, fragile bones)

Question 7

What condition arises from mineralisation defecits?

Answer 7

Osteomalacia (adults)

Ricketts (children)

Question 8

In intermembranous ossification what is the template?

Answer 8

Mesenchymal membranous template

Question 9

What type of bones is formed via intermembranous ossification and give an example?

Answer 9

Flat bones

Skull/clavicle/mandible

Question 10

In endochondral ossification what is the template?

Answer 10

Hyaline cartilage

Question 11

What forms the hyaline cartilage?

Answer 11

Mesenchymal cells

Question 12

Define Wolf’s law?

Answer 12

Bone of a healthy person will adapt to loads under which it is placed

Question 13

What is the cause of giganticism and acromegly and what is the difference between the two?

Answer 13

Pituarty gland tumour resulting in exccessive production of growth hormone, difference is giaganticism is in children and acromegly is in adults

Question 14

Name the hormone that stimulates osteoclastic activity?

Answer 14

RANKL

Question 15

Name the hormone that inhibits osteoclastic activity?

Answer 15

OPG