Bone Health - Lecture 35 Flashcards
Composition of Bone Structure
50% mineral crystals (Calcium phosphate)
50% protein (collagen)
What classifies as a healthy bone
More strong and dense
Two types of Bone
Cortical & Trabecular
Cortical
Compact and long part
Trabecular
Spongy end with red bone marrow
Key Structures of the Bone
Marrow, Periosteum, Blood Supply, ‘physis’s’
What is marrow used for?
Creating different types of cells based on red or yellow marrow
Periosteum
Outer layer wrapped around the bone
Why does the bone have it’s own blood supply
Although it’s a dense structure, it has structures within that require blood to function.
Different ‘physis’s’
Proximal epiphysis, Metaphysis, Diphysis, Distal Epiphysis
Proximal epiphysis & Distal Epiphysis
where bone meets joint; trabecular bone area
Metaphysis (Trabecular Bone Region)
Area for bone growth (growth plates)
When is metaphysis most active
Young and active age
Diphysis
Located on the cortical bone region.
Bone Remodelling
The bone is always in a constant state of turnover; being broken down and built
Two cells involved in bone remodelling
Osteoblasts and Osteoclasts
Osteoblasts
Bone forming/building cells
Osteoclasts
Bone resorbing cells
Step 1 Bone remodelling
Osteoclasts reabsorb cells (break bone down)
Step 2 Bone reabsorption complete
Cavities where the bone was removed
Step 3 Bone Formation
Osteoblasts build bone back in the presence of good nutrition (calcium)
Final step of Bone Remodelling
Bone settles in
Trends in Bone Mass Across Lifespan
- Males peak higher and end higher with bone mass
- Females have a rapid drop at 50-60 due to menopause
How much influence does diet and exercise have on bone mass (%)
20-40%
Danger Zone
Risk getting osteoporosis due to suboptimal lifestyle factors
What does “pediatric disease with geriatric consequences” mean
Lifestyle as a young person can affect your health as an adult
Key messages to prevent osteoporosis
Maximize bone growth young age and minimize bone loss when older
What is osteoporosis characterized by?
Low bone mass/density and deterioration of bone tissue
Is there more osteoblast or osteoclast activity for osteoporosis
Osteoclast; causing greater cavities
Which bone type is affected?
Trabecular bone; cavities increase and less rigid
What risks are associated with loss in bone mass
Fracture + Functionality
How is Bone Mineral Density measured
DEXA
What does DEXA help determine
Bone density, fracture risk, etc.
Where are the main sites of osteoporosis diagnosis
Lumbar Spine and Femoral Neck
How is it osteoporosis scored with DEXA?
Two ways; T-score and Z-score
T-Score
Compares bone density to avg 30 yr old of same sex
Z-Score
Compares bone density to avg. person, same age and sex
What number is normal bone density
> -1.0
What counts as not good?
-1.0-2.5
What number would mean osteoporosis
<2.5
Why do women have a higher chance of experiencing an osteoporotic fracture
- Men have a higher peak
- Females live a longer life so they’re likely to experience it later in life.
- Men being more active at a younger age
What’s the progression of osteoporosis like for males
For Males bone loss slowly trickles away at 35
What’s the progression of osteoporosis for females
Slow but accelerates 5 years after menopause
Why is the progression silent
People aren’t aware of osteoporosis until a fracture occurs
Risk factors for Osteoporosis
- Poor diet
- Increasing age
- Genetics
- Sex
- Physical Inactivity
Symptoms of Osteoporosis
- Pain in lower back
- Cramps in legs and feet
- Dowager’s hump (spine bending forward)
- Fragility Fractures
Main common sites of Osteoporotic Fractures
Vertebral (compression) , Wrist (fall), Hip (fall)
Colle’s Fracture
Outward wrist fracture
Smith’s Fracture
Inward Wrist Fracture
What’s the most likeliest fracture for osteoporotic purposes past the age of 70
Hip fractures
Impacts of QOL after hip fractures (older adults)
Independence and Functionality lost
Mortality risk?
10-20% after 6 months and 21-36% after a year
Prevention and Treatment for Osteoporosis
- Exercise
- Diet
- Medications
- Early Screening/ DEXA for those at risk
