Musculoskeletal Pathophysiology bones A+

Musculoskeletal Pathophysiology bones A+ - Bone turnover o 5-7% recycled weekly o 0.5g enter/leave the adult skeleton each day - deposition organic matrix - mineral resorption release of minerals blood o osteoblasts: build bone hydroxyapatite crystals (calcium +phosphate) o Osteoclasts: degrade (corrode) bone - Calcium homeostasis: depends on a balance between dietary intake, urinary andfecal losses, and exchanges between osseous bone tissue o Regulated by 3 hormones: calcitriol, calcitonin, and parathyroid hormone - Vitamin D is important for the absorption of calcium: produced by the sequentialaction of the skin, liver, and kidneys. Behaves as a hormone o Binds newosteoclasts Osteomalacia Metabolic bone disease o A deficiency of vitamin D lowers the absorption of calcium from the intestines o Inadequate or delayed mineralization o Bone formation progresses to the osteoid formation by calcification doesn’t occur o Soft rather than rigid bone o Symptoms are a pain when weight is put on the affected bone ▪ Also bone fractures, vertebral collapse, bone malformation Rickets Similar pathology to Osteomalacia but usually in children o A bone-softening disease that causes severe bowing of the legs, and deformities tothe pelvis, skull, and rib cage are common o Poor growth and sometimes muscle pain and weakness o Surgery often required o The deformity can improve with the normalization of bone metabolism - Exercise increases bone strength Signs and symptoms of fractures o Impaired function o Unnatural alignment (deformity) o Swelling o Possible muscle spasm o Tenderness and pain o Bruising or discoloration around the break o Impaired sensation o X-ray evidence of a break Fractures o Open fracture: breakthrough intact skin, and bone marrow exposed to the externalenvironment. Risk of infection and osteomyelitis o Pathologic fracture: occurs in the bone that is weakened by disease Egosteoporosis, bone metastasis, primary bone cancer o Comminuted fracture: more than 2 parts of bone, harder to heal with callusformation o Impacted fracture: pressure/weight that causes the break. Impacts or crushes therest of the bone Callus formation. - The bone is broken, causing damage to surrounding tissue and periosteum □ bleeding due to damage to blood vessels inthecortex and marrow. Formation of hematoma organized into the fibrous network (bone needs to be immobile for thisto occur due to CONTINUES...