Skeletal System 2 - Bone Growth and Remodelling Flashcards
What is bone remodelling?
Ongoing replacement of old bone tissue by new bone tissue
The bone remodelling process relies on what 2 factors?
Bone resorption and Bone deposition
What is bone resorption?
Destruction of bone extracellular matrix
Performed by osteoclasts | Removal of minerals & collagen from bone
What is bone deposition?
Formation of bone extracellular matrix Performed by osteoblasts | Addition of minerals & to bone
What percentage of total bone mass is being remodelled at any given time?
5%
What percentage of compact bone is remodelled per year?
4%
What percentage of spongy bone is remodelled per year?
20%
True or False? Remodelling removes injured bone tissue.
True
True or False? Remodelling isn’t triggered by lifestyle factors
False
Is newer bone more resistant or less resistant to fracture than old bone?
more resistant
In resorption, osteoclasts attached to bone at the surface of where?
The endosteum or periosteum
In resorption, Calcium & phosphorus enter osteoclasts by?
endocytosis
What results in Excessive osteoblast activity?
Bones abnormally thick & heavy | Spurs
What results in Excessive osteoclast activity?
Loss of calcium and weakened bones | Osteoporosis
What factors underpin bone growth and remodelling?
Minerals - Calcium | Phosphorus | Magnesium | Fluoride | Manganese
Vitamins - Vitamin A | Vitamin C | Vitamin D | Vitamin K | Vitamin B12
Hormones - Insulin growth-like factor | Thyroid hormones | Oestrogen | Testosterone
What is a bone fracture?
Any break in the bone
What is an open (compound) fracture?
Broken ends of bone protrude through skin
What is a closed (simple) fracture?
Broken ends of bone do not break the skin
What is a Comminuted fracture?
Bone is splintered, crushed or broken into pieces
Smaller bone fragments lie between two main fragments
What is a greenstick fracture?
Partial fracture on one side of the bone
Other side bends
What is a Compression fracture?
Compression force causes fracture in vertebrae
What is a stress fracture?
Series of microscopic fissures that form in bine without
evidence of injury in other tissues
What are the 4 steps of fractured bone repair?
Formation of fracture haematoma
Fibrocartilaginous callus formation
Bony callus formation
Bone remodelling
Bone strength increases in response to what?
Mechanical stress
What type of activities promote increases in bone mass?
Weight bearing
True or False? Ageing promotes accelerated bone loss
True
Are women or men more at risk of osteoporosis?
Women
Process begins during 30’s
30% of calcium lost by 70’s
8% of bone mass lost every 10 years
What Condition which causes porous bones?
Osteoporosis
What is osteopenia?
Low bone mass
What 2 types of medications are used to treat osteoporosis?
Antiresorptive drugs
Slow down the progression of bone loss |
Bisphosphonates
Bone building drugs
Promote increase in bone mass |
Parathyroid hormone (PTH)
Ageing promotes what in bone?
demineralisation
How many people have osteoporosis in England and Wales?
> 2 million people
