Chapter 6 Bones and The Skeletal System

A break in the skin breaking into multiple pieces etc

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Unformatted text preview: hematoma (1) broken vessels form a blood clot granulation tissue (2) fibrous tissue formed by fibroblasts & infiltrated by capillaries callus formation (3) soft callus of fibrocartilage replaced by hard callus of bone in 6 weeks remodeling (4) occurs over next 6 months as spongy bone is replaced with compact bone Healing of Fractures 1 2 3 4 Closed reduction Open reduction Treatment of Fractures fragments are aligned with manipulation & casted surgical exposure & repair with plates & screws Traction is not used in elderly due to risks of long term confinement to bed Electrical stimulation is used on fractures that take longer than 2 months to heal Orthopedics = prevention & correction of injuries and disorders of the bones, joints & muscles hip fractures are pinned & early walking is encouraged Most common bone disease Bones lose mass & become brittle due to loss of both organic matrix & minerals risk of fracture of hip, wrist & vertebral column lead to fatal complications such as pneumonia widow's (dowager's) hump is deformed spine Osteoporosis Postmenopausal white women at greatest risk ERT slows its progress, but best treatment is prevention exercise & calcium intake (1000 mg/day) between ages 25 and 40 by age 70, average loss is 30% of bone mass Phosphate is a component of DNA, RNA, ATP, phospholipids, & acidbase buffers Calcium is needed for communication between neurons, muscle contraction, blood clotting & exocytosis Calcium plasma concentration is 9.2 to 10.4 mg/dL 45% is as Ca+2, rest is bound to plasma proteins & is not physiologically active Phosphate plasma concentration is 3.5 to 4.0 mg/dL & occurs in 2 forms: HPO4 2 & H2PO4 Functions of Calcium & Phosphate Changes in phosphate concentration have little effect Changes in calcium can be serious Ion Imbalances Homeostasis depends on calcitriol, calcitonin & PTH hypocalcemia is deficiency of blood calcium causes excessive excitability of nervous system leading to muscle spasms, tremors or tetanus carpopedal spasm or laryngospasm calcium normally binds to cell surface contributing to resting membrane potential with less calcium, sodium channels open more easily exciting neuron hypercalcemia excessive calcium binding to cell surface makes sodium channels less excessive calcium binding to cell surface makes sodium channels less likely to open, depressing nervous system Carpopedal Spasm Hypocalcemia causing overexcitability...
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