Lecture 3

Question 1

What is healthy bone remodeling

Answer 1

Bones undergo constant remodeling throughout lifetime
- renews every 10 years

Question 2

What does optimal bone density relies on

Answer 2

OsteoCLAST and osteoBLAST

Question 3

What does bone multicellular units (BMU) consist of?

Answer 3

Small clusters of osteocytes, osteoblasts, and osteoclasts

Question 4

(T/F) BMU’s are constantly at rest to maintain optimal bone density and quality.

Answer 4

False
They are always active

Question 5

What is the resting phase of healthy bone remodeling

Answer 5

Pre osteoblast and pre osteoclast are not active and no active turnover of bone

Question 6

What is the activation phase of healthy bone remodeling

Answer 6

Apoptosis of osteoCYTES, physical stress, and hormones/cytokines stimulate pre osteoBLAST to activate BMU
- pre osteoBLAST releases RANKL and M-CSF to stimulate the pre osteoclasts to mature and become active osteoCLAST and osteoBLAST

Question 7

What is the resorptive phase of healthy bone remodeling

Answer 7

Mature/active osteoCLAST release acid/enzymes to break down bone and create RESORPTION cavity

Question 8

Other than acid/enzymes being released, what else is being released in the resorptive phase

Answer 8

Growth factors and bone morphic proteins (BMP)

Question 9

What is the reversal phase in healthy bone remodeling phase

Answer 9

Macrophages are being activated and clean up the resorptive cavity to prepare for new bone

Question 10

What is the formation phase in healthy bone remodeling

Answer 10

Mature osteoBLAST synthesize/secret extracellular bone matrix

Question 11

What is osteoprotegerin (OPG)

Answer 11

Inhibits osteoCLAST activity
- protects bone from excessive osteoclastic activity to maintain optimal bone density

Question 12

What is the mineralization phase in healthy bone remodeling

Answer 12

Matrix that surrounding the osteoBLAST mineralizes and the osteoBLAST “becomes” an osteoCYTES
- returns to resting state

Question 13

What is osteoporosis

Answer 13

Severe decrease in bone mineral density (BMD)
Bone density 2.5 SD or lower

Question 14

What is primary osteoporosis

Answer 14

DNA caused low bone density
Type 1 - menopause
Type 2 - age related

Question 15

What is secondary osteoporosis

Answer 15

Low bone density secondary to medication or disease

Question 16

What ages are peak bone mass

Answer 16

25-30 years old

Question 17

How long does peak bone mass plateaus

Answer 17

3-5 years

Question 18

(T/F) the rate of bone loss is the same for men and women before menopause

Answer 18

True

Question 19

What effect does glucocorticoid have with bones

Answer 19

Decreases bone mass
- first 6 months largest rate of bone loss occurs

Question 20

What is FRAX

Answer 20

Fracture risk assessment tool
Online questionnaire that predicts fracture risk

Question 21

What is osteomalacia

Answer 21

Insufficient mineralization of bone
- matrix fails to mineralize

Question 22

What are the etiology of osteomalacia

Answer 22

Poor vit d intake
Intestinal disease that impairs absorption
Renal disease
Medication
Tumors

Question 23

Rickets is also known as what

Answer 23

Childhood osteomalacia

Question 24

What image is presented on an x-ray if you have osteomalacia

Answer 24

Deformed bowing long bones

Question 25

What is Paget’s disease of bone

Answer 25

Chronic bone disorder Severe bone deformation > 50 years M > F (8:1)

Question 26

What is a benign primary bone tumor

Answer 26

Well differentiated and slow growing - bone attempts to contain growth by forming a sclerotic rim around tumor

Question 27

What is a malignant primary bone tumor

Answer 27

Undifferentiated and fast growing - aggressive growth and expands beyond cortex

Question 28

(T/F) solid benign reactions are benign tumors whereas onion skin, spiculated, and codman’s triangle are malignant tumors

Answer 28

True