Download Bone Remodeling

Bone Remodeling
Bone Remodeling
• Homeostasis process- regulates Ca in the
blood
• involves bone formation and destruction
• Controlled by hormonal and mechanical
factors.
• Occurs constantly with every bone in the
body.
Bone Remodeling
• Bone formation is called “bone depositing”.
• Bone destruction is called “bone resorption”.
Bone Remodeling
• Hormonal Factors affecting bone deposit and
resorption:
– Are governed by negative feedback control
systems.
– Depend upon blood levels of calcium.
Bone Depositing
• When Calcium blood levels rise above normal:
– Detected by the Thyroid (control center)
– Response: Releases the hormone calcitonin
– Signals the osteoblasts to undergo bone
depositing (builds bone)
– Effect: Calcium blood levels drop & Thyroid stops
producing calcitonin
BONE REMODELING CYCLE
Bone Remodeling
• When Calcium blood levels fall below normal:
– Detected by the Parathyroid (control center)
– Response: Releases parathyroid hormone (PTH)
– Signals the osteoclasts to perform Bone resorption
(breaks down bone)
– Effect: Calcium blood levels rise & Parathyroid
stops producing PTH
BONE REMODELING CYCLE
Bone Remodeling
• Mechanical Factors can also stimulate this
process:
– Weight bearing exercises put stress on the bone
– The stress releases signals to build bone in order
to withstand that stress, making bone stronger
– Used in physical therapy for disorders in weak
bone (such as osteoporosis)
OVERVIEW:
• Homeostatic process that regulates ____________________________ by
_______________________________ and ___________________________ bone
• Regulated by what two factors:
• Occurs in what circumstances:
• Bone formation is called:
• Bone destruction is called:
• When regulated by hormones, what type of feedback
• What is monitored to determine hormone release?
HOW MECHANICAL FACTORS INFLUENCE BONE REMODELING:
BONE DEPOSITING:
• Control center:
• Trigger/stimulus:
• Hormone:
• Effect of hormone (what does it talk to?):
• Result:
• How does the mechanism end?
Draw a diagram below:
BONE RESORPTION:
• Control center:
• Trigger/stimulus:
• Hormone:
• Effect of hormone (what does it talk to?):
• Result:
• How does the mechanism end?
Draw a diagram below: