Bone Histology and Physiology Flashcards
What percentage of bone matrix is Inorganic, organic and water?
50% inorganic
25% organic
25% water
What crystalised minerals make up the inorganic matrix of bone?
- Hydroxyapatite (Ca phosphate and Ca hydroxide)
- Magnesium hydroxide
- Fluride
- Sulphate
What makes up the 25% organic aspect of the bones?
Collagen fibres
What is calicification?
A process of crystallisation of minerals within a collagen framework
What does the hardness of a bone depend on?
Minerals
(soaking bone in acid disolvesminerals making it rubbery and flexible)
What does the flexability of a bone depend on?
Collagen
(removal of collagen makes bone brittle)
What is the diaphysis of bone?
Shaft or body
What is the epiphysis of a bone?
ends of the bone
What is the metaphysis of a bone?
where diaphysis and epiphysis join
– epiphyseal plate (cartilaginous, during growth)
– epiphyseal line (bony, after growth)
What is the periosteum?
outer sheath of bone
What is a medullary cavity?
hollow part of bone that cointains yellow marrow
What is the endosteum?
Thin membrane lining the medullary cavity
What are osteogenic cells?
Mesenchymal stem cells
- Only bone cell to undergo cell division
- Their daughter cells are osteoblasts
Where are osteogenic cells found?
- Inner portion of periosteum
- Endosteum
- Blood vessels containing canals
What are osteoblasts?
Bone building cells
What do oseoblasts do?
- Synthesise and secrete collagen/matrix
- Initialise calcification
- Become trapped in matrix (10%)
- Become osteocytes
What are osteocytes?
Mature bone cells
(Make up 90% of bone cells)
What do osteocytes do?
-Maintain daily bone metabolism
- Mechosensors and mechanotransmitters
- Exchange of nutrients/waste
