Bones Flashcards
The bone is made up of
A matrux and cellular components.
What are the two matrix components of the bone?
Minerals: Calcium, phosphate and magnesium
Organic compounds: Type I collagen
The cellular portion of the bone is made up of what three cells?
Osteoblasts
Osteoclasts
Osteocytes
What are the functions of the bone?
Mechanical
Protective
Metabolic
The cortical bone perfeorms what functions of the bone?
Mechanical and protective
What type of bone performs the metabolic function?
Trabecular bone
What does the mechanical function of the bone consist of?
The bones serve as levers for skeletal muscle movement. Our tendons attach muscle to the the bones to move our extremities
What does the protective function of the bone consist of?
The bones provide a rigid framework for structure. This protects vulnerable organs from injury.
What dies the metabolic function of the bone concist of?
The bone contains hematopoietic tissue in its marrow which serves as reservoir for minerals like calcium and phosphate
Bone turnover happens continuously at regions called
Remodeling units
What is the role of osteoclasts?
They resorb old bone by digesting organic matrix, releasing minerals into the blood.
What is the role of osteoblasts?
They form new bone by synthesizing the organic matrix, especialky type I collagen, depositing minerals to solidify new matrix
Turnover rates are affected by
Calcium, phosphate and magnesium metabolism, and hormones like pth and Vitamin D
Bone disease can be a product of what three issues?
Disorders of hormones and mineral metabolism
Metabolic bone disease
Idiopathic
List the metabolic bone diseases.
Osteoporosis Osteomalacia Ricket’s Renal osteodystrophy Scurvy
What us the most common metabolic bone disease?
Osteoporosis
What is osteoporosis?
This is a metabolic bone disease inwhich there is decease in total bone mass andd density
What auses osteoporosis?
Aging
Endocrine issues
What is osteoporosis caused by old age called?
Senile osteoporosis
Why does aging cause osteoporosis in humans?
Theres decreased osteoblast activity with age.
In this condition, osteoclast activity exceeds osteoblast activity which causes low bone mass and density
Osteoporosis
How do endocrine issues cause osteoporosis?
Decreased estrogen
What are the symptoms of osteoporosis?
Bone fracture
Loss of teeth
Compression fractures in vertebrae
What are the two suntypes of osteomalacia?
Ricket’s
Renal osteodystrophy
This is an adukt disorder of mineralization during bone formation caused by inadequate calcification of matrux resukting in bone softening
Osteomalacia
There is an increase of what substance in osteomalacia?
Increased unmineralized osteoid (collagen)
Increased osteoblast activity in osteommalacia results in increase of what enzyme iptrying to compensate?
ALP
What are the causes of osteomalacia?
Vitamin D deficiency
Hypophosphatemia
Kidney disease/failure
What us the most commone cause of osteomalacia worldwide?
Vitamin D deficiency
What are the symptoms of osteomalacia in adults?
Severe bone pain
Skeletal fractions
Soft bone due to lack of mineralization
What is ricket’s?
Child disorder of mineralization defect
What causes Ricket’s?
Lack of active vitamin D or vitamin D resitance
Calcium or phosphate deficiency
A 1 month okd babt who is still breastfed and does not receive adequate sunkights is at hugh risk of what disease?
Risket’s
What enzyme deficiency in the kidneys leads to no active vitamine D production?
1-a-hydroxylase
Although vitamin D levels are normal in some patients with osteomalacia, what vitamin D associated condition may cause the disease?
Vitamin D resistance due to defect in receptor
What is renal osteodystrophy?
This is a chronic renal failure associated wuth complex bone abnormalities and mineral issues
In ROm decreased active vitamin D from kidmey failure causes
Hypocalcemia which induces PTH release.
What condition is an effect from overeactive PTH from lack of vitamin D?
Osteomalacia
What is scurvy?
Inadequate collagen synthesis due to lack of vitamin C (ascorbic acid)
What vitamin is needed for the sysnthesjs of collagen?
Vitamin C
What are the symptoms of scurvy?
Fractures
Bleeding gums and vessels
Loss of teeth
What us a ither name for Paget’s disease?
Osteitis deformans
Whats us the one idopathic bine disease?
Paget’s
What is paget’s disease?
Thus is bone resorption followed by chaotic replacement of bone architecture
Paget’s disease usually sees hugh levels of what enzyme?
ALP
List the symptoms of PD
Arthritis Bone pain Nerve compression in vertebral column Closure of ear canal in inner ear Deafness
What are analyzed first in the lab to determine bine disease?
Minerals. If abnormal, hormones are analyzed
What is the use of biochemical marlers of bone formation of resorption?
Monitoring therapy Selection of patients appropriate for therapy Prediction of bone loss Prediction of bone fracture risk Monitoring bone cancer
What are the markers of bone formation?
PINP/PICP
ALP
Osteocalcin
What is the most sensitive marker of bone formation?
PINP
What are the markers of bone resorption?
NTx
CTx
DPD/PYD
TRAP/TRACP
What market is hughly specific for bone resorption?
NTx
Why should Creatine and BUn be measured with bone urinary markers?
Because urine markers can show fakse resukrs if kidney issues are present
These proteins serve to stabilize collagen diring its synthesis?
DPDPYD
This marker reflects osteoclasts number and activity
TRAP
