Bone Remodelling

Question 1

What is Wolf’s Law?

Answer 1

Bone will grow and remodel in response to forces and demands placed upon it. Thus, a bone will adapt to its needs

Question 2

What is the role of gravitational forces?

Answer 2

To support body weight

Question 3

What is a muscle pull?

Answer 3

A bony landmark formed from where muscles are attached

Question 4

What is the role of bone deposition and bone restoration?

Answer 4

To control bone remodelling

Question 5

At what rate is bone recycled?

Answer 5

5-7% per week

Question 6

How long does it take for a bone to be completely replaced?

Answer 6

~3-4 years for spongy, ~10 years for compact bone

Question 7

Child/adolescent

Answer 7

deposition > resorption

Question 8

Adult

Answer 8

deposition = resorption

Question 9

Elderly

Answer 9

deposition < resorption

Question 10

What is an osteoblast and what is its role?

Answer 10

Osteoblast is a bone forming cells and is responsible for bone deposition. The role includes repair following an injury and increasing bone strength

Question 11

What is an osteocyte and what is its role?

Answer 11

Osteoblast is a bone destroying cells and is responsible for bone resorption. The role includes destroying bone into minerals so they can be used by the body

Question 12

What happens when blood calcium levels are low?

Answer 12

When parathyroid glands detect low levels, it releases parathyroid hormone

Question 13

What is the role of the parathyroid hormone?

Answer 13

PTH stimulates osteoclasts to breakdown bone and releases it as calcium into the bloodstream

Question 14

What happens when blood calcium levels are high?

Answer 14

When the thyroid detects a high level, it releases calcitonin

Question 15

What is the role of calcitonin?

Answer 15

Calcitonin stimulates osteoblasts, removing calcium from the bloodstream and deposits as bone