RIU 330 Lecture Notes - Lecture 75: Dwarfism, Malabsorption, Synovial Joint
10 Nov 2020
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Document Summary
Metabolic diseases affecting growth, formation, removal of bone. Achondroplasia: form of dwarfism caused by abnormal endochondral bone formation in growing long bones; caused by mutation of gene of fibroblast growth factor receptor 3. Osteogenesis imperfecta: bone defect caused by mutations of gene for collagen i. Osteopetrosis: thick bones resulting from defect in function of osteoclasts. Location: multiple sites; most important: carpal bones, head of femur. Multifactorial disease characterized by absolute reduction of total bone mass. Age related: one third of population > 85 have it. Etiology unknown, but certain factors are known to predispose. Hormonal disturbances: excess cortisol; deficiency of sex hormones. Dietary disorders: vitamin c or calcium deficiency, malabsorption of food. Softening of bones: result of inadequate mineralization of organic matrix (osteoid) Caused by deficiency of vitamin d, inadequate metabolic processing, activation of vitamin d, or disturbances of phosphate metabolism. Inadequate intake: malnourished children in africa, food faddists in u. s. Inadequate exposure to sunlight: people living above.
