Bone remodelling

Question 1

When is bone remodeled? (4)

Answer 1

1) Form bone shape
2) Replace woven with lamellar
3) Repair damage
4) Obtain calcium

Question 2

What influences bone remodelling?

Answer 2

Calcium lvl
Phosphate lvl

Question 3

How is bone remodelling controlled?

Answer 3

Negative feedback
Bone deposit
Deposit Ca2+ into bone

Question 4

Outline bone resorption?

Answer 4

1) Osteoclasts break bone
2) Calcium and phosphate released

Question 5

Define coupling?

Answer 5

Osteoblast communicate with osteoclast- ensure bone formation at site of resorption

Question 6

Define balance?

Answer 6

Amount bone removed osteoclast should replaced by osteoblast

Question 7

Define bone modelling?

Answer 7

Gross shape altered- bone added/taken away
During growth

Question 8

Define remodelling?

Answer 8

All bone altered- new replaces old

Question 9

State 2 reasons for bone remodelling?

Answer 9

1) Remove and replace old bone
2) Mobilise mineral for homeostasis

Question 10

Outline bone remodelling process?

Answer 10

1) Injury results in osteoclasts gathering
2) Osteoclasts attach surface- projections secrete acid
3) Acid dissolves bone mineral- form pits
4) Osteoblasts secrete osteoid
4) Osteoid matrix mineralised form bone

Question 11

Function primary osteons?
Function secondary osteons?

Answer 11

Primary osteons- fill holes left during rapid form
- don’t cut through lamellae
Secondary osteons- drive remodelling
- cut through lamellae