Normal Bone Function Flashcards
What is the purpose of the skeleton
Raise us from the ground against gravity
Basic body shape
Transmits body weight
System for movement
Protects vital structures
Houses bone marrow
Mineral storage
How many bones does a adult have
206
What are the different classifications of bone
Long bones
Short bones
Flat bones
Irregular bones
Sesamoid bones
WhAt are long bones
Tubular shape with hollow shaft and ends expanded for articulation with other bones
What are short bones
Cuboidal in shape
What are flat bones
Plates of bone often curved protective function
What are irregular bones
Various shapes
What are seamoid bones
Round oval nodules in a tendon
What are the different structures of bone which are visible by eye
Cortical
Trabecular
What is a cortical structure of bone
Compact
Dense solid
Only space is for cells and blood vessels
What is trabecular bone
Cancellous
Spongy bone
Network of bony struts
Which look like sponge
Many holes
Filled with bone marrow
What are the type of bone structure which cannot be seen by the eye
Woven and lamellar
What is woven bone
Disorganised
No clear structure
Made quickly
What is lamelllar bone
Organised
Layered structure
Made slowly
What is and adult bone composed of
Mineral
Organic matrix = collagen and non-collagenous proteins
Water
What is bone
Bone is a composite
What does mineral in the bone provide
Stiffness
What does collagen in the bone provide
Elasticity
What is bone modelling
Gross shape is altered so bone is added or taken away
What is bone remodelling
All of the bone is altered so new bone replaces the old bone
What are the cells of bone
Osteoclasts
Osteoblasts
Osteocytes
Bone lining cells
What are characteristics of osteoclasts
Multi-nucleated
What are characteristics of osteoblasts
Plump and cuboidal shape
What are characteristics of osteocytes
Stellate
Entombed in bone
What are characteristics of bone lining cells
Flattened
Lining the bone
What is the origin of osteoblasts
Mesenchymal stem cells
What do osteoblasts do
Form bone
Produce type I collagen
Deposit calcium
High alkaline phosphatase activity
Make non-collagenous proteins
Secrete factors that regulate osteoclasts eg RANKL
What do osteoclasts do
Resorb bone
Dissolves the mineralised matrix
Breakdown the collagen in bone
High expression of TRAP and cathepsin K
Reasons for bone remodelling
Form bone shape
Replace woven bone with lamellar bone
Reorientates fibrils and trabeculae in favourable direction for mechanical strength
Response to loading
Repair damage
Obtain calcium
