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82 Cards in this Set
- Front
- Back
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Parathyroid hormone does what? |
Increases blood calcium levels and regulates phosphate |
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PTH achieves this by |
Releasing calcium from bone Stimulating vitamin D |
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What does Vitamin D do? |
Enhances uptake of calcium in gut Increases Ca and PO reabsorption from bone |
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Calcutonin does what? |
Decreases blood calcium level By inhibiting osteoblast activity By reducing calcium reabsorption |
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PTH receptors are located on |
Osteoblasts |
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Osteoclast precursors have what receptors on their cell membranes? |
RANK |
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X have the ligand for this receptor (RANK) on cell membranes called X |
Osteoblasts RANKL |
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PTL upregulates RANKL which binds to RANK and stimulates... |
Differentiation of osteoclasts |
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Osteoblasts also produce osteoprotegrin which prevents X by binding to X |
Reabsorption RANKL |
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The ratio of RANKL:Osteoprotegrin determines |
Bone reabsorption |
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Congenital bone disease: osteogenesis imperfecta is known as |
Brittle Bone Disease |
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OI is an autosomal.. |
Dominant |
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The skeleton is fragile due to the defective |
Collagen chain |
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OI type II is usually.. |
Fatal in utero or perinatal |
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OI Type I leads to |
Increased childhood fractures |
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Extra-skeletal manifestation of OI? |
Blue Sclera |
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Achrondoplasia is |
Dwarfism causes by mutation on fibroblast growth factor receptor 3: activation |
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Activation of FGFR3 inhibits chondrocyte proliferation and therefore |
Affects Growth Plates |
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Growth plates are disorganised and hypoplastic therefore affecting all |
Long bones |
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Achrondroplasia is autosomal |
Dominant and heterozygous |
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Chrondroplasia causes Lordosis and therefore |
Bowed legs, stunted extremities. |
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Osteopetrosis is the reduced activity of |
Osteoclasts |
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Osteoclasts in Osteopetrosis can not excrete |
H+ ions to dissolve bone mineral |
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The bones in Osteopetrosis are |
Dense but brittle and easily fractured |
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Clinical effects of Osteopetrosis |
Fractures Spinal nerve compression Recurrent infection Hepatosplenomegaly |
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Bone marrow transplant in Osteopetrosis to provide X can be effectivr |
Healthy osteoclast precursors |
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Four main acquired Bone Diseases |
Osteoporosis Rickets and Osteomalacia Paget's disease Hyperparathyroidism |
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Osteoporosis is the |
Loss of Bone mass, increased porosity. |
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In osteoporosis, the X and X are thinned |
Trabeculae Cortex |
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Examples of areas with lots of trabecular bone: |
Vertebrae Wrists Neck of femur |
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Osteoporosis causes |
Old age Post menopausal decrease in oestrogen Disuse and reduced activity Prolonged steroid use (RA) Some endocrine disease eg Cushings |
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Menopause and Age changes in Bone |
Back (Definition) |
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Diagnosis of Osteoporosis is via sensitive DEXA because... |
Asymptomatic pre fracture Serum ALP, Ca and Pi level unreliable 30-40% reduction in bone mass needed to be seen via x ray |
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Clinical outcomes of Osteoporosis |
Pathological fractures due to falls Back pain and kyphosis due to compression fractures Hip replacements - fractured neck of femur |
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Treatment of Osteoporosis |
Prevention (diet and exercise) Bisphosphonates, oestrogen receptor agonists, PTH |
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Osteomalacia is the adult version of |
Rickets |
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Osteomalacia is causes by failure of |
Correct mineralisation of osteoid leading to soft bones |
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The bones affected in Osteomalacia |
Cortical and trabecular |
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Osteomalacia is caused by a lack of |
Vitamin D |
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Osteomalacia lack of Vitamin D can be due to |
Poor diet Poor sunlight Malabsorption Renal disease |
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Symptoms of Osteomalacia |
Bone pain Untreated - structural abnormalities such as bowing Early signs in children can be swelling of bone epiphyses. |
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Diagnosis of Osteomalacia |
X ray Labs show low serum Vitamin D |
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Treatment of Osteomalacia |
Supplementation Prevention advice |
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Hyperparathyroidism is affecting |
Calcium metabolism |
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Calcium metabolism changes cause |
Unchecked PTH secretion and osteoclast resorption |
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Types of Hyperparathyroidism |
Primary - Tumour Secondary - Low serum calcium caused by renal disease, causing hyperplasia of parathyroid glands |
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Paget's disease is |
Excessive bone resorption by osteoclasts followed by haphazard bone formation |
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This excessive resorption results in |
Potential increase in bone mass but structurally weak, immature woven bone. |
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Metabolic demand is therefore |
High due excessive bone turnover |
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Symptoms of Pagets |
Bone pain, 80% in axial skeleton and consequences of nerve impingement |
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Paget's can also increase risk of |
Osteosarcoma Nerve compression Pathological fracture Heart Failure |
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Osteomyelitis is the |
Inflammation of the bone and marrow cavity |
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Osteomyelitis is almost always caused by |
Infection |
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Osteomyelitis occurs as either |
Primary bone disease Result of systemic infection |
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Osteomyelitis most often affects |
Long bones and vertebrae |
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Common organisms causing Osteomyelitis |
Pyogenic bacteria TB |
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Bone tumors are most often |
Metastatic |
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75% of bin tumors in adults come from
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Prostate
Breast Kidney Lung |
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The metastatic spread of bone tumor is via |
Lymphatic Blood Direct and Spinal seeding |
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Primary bone tumors (barring haematopoietic) are either |
Benign or malignant |
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Benign bone tumours include |
Bone forming Osteolytic Fibrous tumours |
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Malignant bone tumours inclufr |
Osteosarcoma Ewing's sarcoma |
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Benign or malignant, Which is more common? |
Benign, although malignant more common over 40. |
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A benign, exophytic growth of bone is caused |
Osteoma |
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Bone tumours found with cartilage are called |
Osteochondroma |
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Fibrous dysplasia is |
Fibroblast proliferation in medullary cavity which expands and distorts bone |
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A myeloma is a tumour of |
Plasma cells often found in bone |
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Ewing's sarcoma is |
A highly malignant, neuroectodermal tumour. Affects young 10-20 Common in: Pelvis Lower limb long bones Ribs |
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Osteosarcoma makes up % of malignant primary bone cancers |
20% |
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Osteosarcoma affects more gender than gender |
Men than women |
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Osteosarcoma affects more gender than gender |
Men than women |
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Under 20 the cause of Osteosarcoma is |
Primary |
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Osteosarcoma affects more gender than gender |
Men than women |
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Under 20 the cause of Osteosarcoma is |
Primary |
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In the elderly, Osteosarcoma is usually |
Secondary to Paget's or Radiation |
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The gross features of Osteosarcoma include |
Grittiness White Extending beyond bony cortex and periosteum into soft tissue |
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The gross features of Osteosarcoma include |
Grittiness White Extending beyond bony cortex and periosteum into soft tissue |
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Radiological features of Osteosarcoma: |
Mass with indistinct, infiltrating margins. Mix or blast if and lytic activity Triangular shadow between cortex and periosteum often seen |
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The gross features of Osteosarcoma include |
Grittiness White Extending beyond bony cortex and periosteum into soft tissue |
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Radiological features of Osteosarcoma: |
Mass with indistinct, infiltrating margins. Mix or blast if and lytic activity Triangular shadow between cortex and periosteum often seen |
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Histological features of Osteosarcoma |
Poorly differentiated, most common variety is medullary. Essential to see mineralised bone/osteoid production by malignant cells. |
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Prognosis of Osteosarcoma |
Aggressive and metastatic Long term survival good, 60-70% |
