Skeletal System Flashcards
What are the 5 competing functions?
1) Structure/support
2) Protection
3) Movement
4) Calcium storehouse
5) Blood cell production
“Living/adaptable”
1) Growth
2) Repair (macrodamage, microdamage)
3) Remodel
What is covering the medullary cavity and the pores on the spongy?
Endosteum
What is covering the superficial layer to compact bone?
Periosteum
What is the space within the diaphysis filled with?
Bone marrow
What are the 3 ways that bone gets blood supply?
1) Periosteal vessels
2) Nutrient arteries (Nutrient foramen)
3) Epiphyseal vessels
Trabecular bone structure consists of…
Network of plates and rods
Porous
Bone Marrow
What are the 3 types of bone cell?
1) Osteoblast
2) Osteoclast
3) Osteocyte
Osteoblast…
(Deposition)
Growth
Repair
Remodeling
Osteoclast…
(Resorption)
Unloading
Repair
Remodeling
Osteocyte…
(Maintenance)
Does both blast and cost but takes care of the microdamage
Extracellular matrix composition
Organic (Collagen, gel)
Inorganic (Hydroxyapatite)
Remain tissue volume (Water)
Matrix composition
1) Collagen (25-30%) Type 1
2) Gel (5%) Glycosaminoglycan (GAG)
3) Mineral (65-70%) Ca Phosphate Crystals (Hydroxyapatite)
Compliant %
25-30% collagen
65-70% mineral
Brittle %
20% collagen
80% mineral
Compressional Loading…
Increased mass & Cross-sectional area
The rate of deposit and resource depends on…
What we do…Body Weight…GRF…Adaptation… aging causes more reserve than deposition
Tensile Loading…
Tubercles, tuberosities, lines
Deposition vs. Reposition
Bone Quantity (mass)
1) Age
2) Activity level
3) Hormones
Age:
Fetal - 25 yrs
25 - 50 yrs
50 yrs+
Deposition is greater than resorption
Little change during 25-50
Resorption is greater at 50+
Activity:
Exercise - over time will add bone mass
Inactivity causes injury/diseases
Microgravity
What hormone inhibits osteoclasts in Osteoporosis patients?
Estrogen
Exercise can only help with what % a year for bone mass?
1%, exercise young!
What are the two hormones that effect bone mass?
Estrogen and Parathyroid
