Bones, Fractures and healing Flashcards
(50 cards)
Function of the bones
Framework for organs -Supports lungs, heart
Protective function- Ribcage-Lungs,heart Skull-brain Vertebrae- spinal cord
Mobilise
Production of blood cells
Regulation of calcium homeostasis
What are the two main categories of bones and what do they consist of?
Axial- central, skull and spine encasing central nervous system
Appendicular- role of ambulation and movement. bones of the limn
What type of growth do irregular bones grow?
By both intramembranous and endochondral ossification
What are the different parts of the long bone?
Epiphysis- rounded end of a long bone covered in articular cartilage - terminal portion
Metaphysis- Where it starts to flare out on either end
Diaphysis- Long shaft of the bone
What proportion of skeletal mass is corticial bone
~80%
Why is the femur clinically important?
Mostly likely place for elderly people to get a hip fracture
What are Osteoprogenitor Cells
Multipotent
Differentiated from mesenchymal stem cells which are pluripotent and they differentiate into osteoblasts
What is one of the main transcription factors involved in coordinating mesenchymal stem cells into osteoprogenitor cells into
RUNX2
What is RUNX2
one of the main transcription factors involved in coordinating mesenchymal stem cells into osteoprogenitor cells into
What do osteoblasts produce?
Type I collagen
ALP — initiates calcification
Calcium phosphate
Depositing calcium and phosphate crystals in the form of calcium phosphate and calcium and calcium hydroxyapatite
What is the half-life of osteocytes?
t1/2 —25 years
What is the osteocytes roles?
mechanosensory role and important in bone remodelin
How do osteoclasts do their function
Bind to the surface of variable with protein osteopontin
acidified the extracellular fluid between ruffled border between the bone
aids in breaking down the matrix and mineralised portion of bone
What is osteopontin?
Proteins that help osteoclasts to bind to variable
What is the structure of osteoclasts? Importance
Ruffled border increases surface area to secrete proteins active transport process Secretes: TRAP osteopotin Cathepsin K
What is the function of TRAP?
involved in producing reactive oxygen species that breaks down bone matrix
What is Cathepsin K ?
protease that breaks down the type one collagen bone matrix
What are the percentages of the composition of the bone matrix?
Organic ‘osteoid’ - 25%
Inorganic- 50%
Water - 25%
What is remodelling key for?
Adapting to new physical activity (Putting under new stress)
After trauma and after bone heals in re-establishing the normal architecture
What happens when osteoclastic activity predominates over osteoblastic activity
Osteoporosis- weak bones prone to fractures
How is osteoporosis caused?
osteoclastic activity predominates over osteoblastic activity
What happens when osteoblastic activity predominates over osteoclastic activity
osteopetrosis bones like marble
also known as bone marble diesease
What is disuse osteopenia
where low bone density because not using those bones ( not enough stress) because of injury
How does bone break?
Hooks law
- Strain on bone ‘elastic material’ back to its original shape
too much strain elastic limit will break bone
apply a force to one side of a bone
nearest side is going to be compressed and bone is strong in compression. heals very well in compression
tension because bone is being pulled apart-
Bone hates tension and cant heal tension
Increase in force tension increases tension
tensile stresses increase, and the bone will break
