Structure and Function of Bone Flashcards
What is the function of bone
Structural function Mobility Support Protection of body Storehouse for essential minerals
What are the 2 different types of osseuous tissues
Compact - (80% of total mass), solid hard layer, external layer to all bones
Spongy - (20% of total mass), honeycomb network, found in inner parts of axial skeleton and epiphyses of long bones
Describe the compact (cortical) bone
Denser than spongy (trabecular) bone but less flexible.
Oseton = concentric rings (lamellae) of calcified matrix surrounding vertically orientated blood vessels
Describe the spongy (trabecular/cancellous) bone
Lattic like and it’s light.
Well organised, along lines of stress - gives strength and resistance against stress and forces without breaking
Oseteocytes in lacunae on the surface of the trabeculae
Nutrients directly from the blood in the medullary cavities
What are the different cell types of bone
Osteogenic/osteoprogenitor cells = undifferentiated cells
Osteoblasts = build matrix & collagen fibres but can’t divide
Osteocytes = mature cells
Osteoclasts = clear bone cells
Explain bone cells
Bones continually modelling through childhood and adolescence
Much of cellular activity in bone consists of removal and replacement at same site, process called remodelling
Many things can interfere with development of a strong and healthy skeleton e.g. osteoporosis
What can go wrong in bone growth
Low bone density (osteoporosis)
Osteogenesis imperfecta
Bone cancer and infections
What are the 4 different types of blood supply and describe them
Periosteal arteries - periosteum and outer osteons of compact bone
Nutrient arteries - medullary cavity and osteons of inner compact bone
Metaphyseal arteries - spongy bone and marrow in this area
Epiphyseal arteries - spongy bone and marrow in this area
What is remodelling affected by in the dynamic skeleton
Age Mechanical stress Genetics and environmental Calcium & phosphate levels Hormones
What effects can occur with age
Demineralisation from age of 40 years - osteoponeia Reduces 1% per year Worse in women 40-45 years Osteoporosis Care when treating
What are the effects of mechanical stress
Weight bearing is important for developing and healing
Relevant to the weight bearing status of a patient
Lack of activity results in loss of bone
Weight bearing activity builds bone
The elderly may respond differently
