Bone

Question 1

Alkaline phosphatase?

Answer 1

Enzyme found in bone and liver. Major protein present in bone tissue

Question 2

Acidic vs alkaline environment. Which is good for bone deposition vs bone resorption

Answer 2

Alkaline environment for calcium deposition

Acidic for calcium resorption

Question 3

Estrogen in bone remodeling

Answer 3

• Inhibits apoptosis of osteoblasts → ↑ bone formation
• Stimulates apoptosis of osteoclasts → ↓ bone resorption
• Stimulates closure of the epiphyseal plate (in puberty)

• At low levels → ↑ bone resorption → can result in osteoporosis

Question 4

Which cell type has PTH receptors

Answer 4

Osteoblasts

PTH binds to osteoblasts, the cells responsible for creating bone. Binding stimulates osteoblasts to increase their expression of RANKL and inhibits their secretion of Osteoprotegerin (OPG).

Question 5

How to activate osteoclasts

Answer 5

Increase in MCSF and RANKL

Question 6

what does estrogen do to osteoclasts?

Answer 6

Decrease its activity

Stimulate OPG synthesis, Decrease MCSF and RANK production

Question 7

Stimulated by transforming growth factor-beta (TGF-β), and bone morphogenic proteins

Answer 7

Osteoblasts

Question 8

Bone-building cells that differentiate from osteoprogenitor cells

Answer 8

Osteoblasts

Question 9

the enzyme that cleaves inorganic phosphate off various substrates to make it available for mineralization

Answer 9

alkaline phosphatase (ALP)

Question 10

Osteoclasts

Answer 10

Bone-dissolving multinucleated phagocytes that degrade mineralized bone and are formed via fusion of monocyte precursor
Have calcitonin receptors

Question 11

RANKL

Answer 11

Ensures fusion and differentiation into activated osteoclasts and prevents their apoptosis

Question 12

Regulation of bone remodeling

Answer 12

Mechanical load
RANK
RANKL
OPG
M-CSF
negative feedback by osteoclasts
PTH, estrogen 
Vit D