1. About 10% of bone is replaced every year in an adult skeleton
Bone Remodeling
constant balance of bone deposit and removal that occurs throughout your life
bone deposit occurs at a greater rate when bone is injured
bone resorption allows calcium of degraded bone matrix to move into the blood.
About 10% of bone is replaced every year in an adult skeleton

2. osteoblasts osteoclasts Maintenance of Bone bone formation
bone reabsorption
osteoblasts
osteoclasts

3. Control of Remodeling Hormonal
 Rising blood Ca2+ levels trigger the thyroid to release calcitonin 
 Calcitonin stimulates calcium salt deposit in bone 
 Falling blood Ca2+ levels signal the parathyroid glands to release Parathyroid hormone (PTH) 
 PTH signals osteoclasts to degrade bone matrix and release Ca2+ into the blood 

4. Hormonal effects osteoblasts osteoclasts Calcitonin (CT) from thyroid
bone formation
bone reabsorption
osteoblasts
osteoclasts
Calcitonin (CT) from thyroid
Parathyroid hormone (PTH) from parathyroid

5. Before age 25 osteoblasts osteoclasts Increase bone mass
bone formation
bone reabsorption
osteoblasts
osteoclasts
Before age 25

6. bone formation
bone reabsorption
osteoblasts
osteoclasts
Age 25-50

7. Age 50-on osteoblasts osteoclasts Decrease bone mass bone formation
bone reabsorption
osteoblasts
osteoclasts
Age 50-on

8. Stress increases bone density
Stress effects
bone formation
bone reabsorption
osteoblasts
osteoclasts
Stress increases bone density