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Unformatted text preview: Skeletal System I. General Info a. Its alive b. High rate of turnover b.i. Each year we replace/remodel about 10% of our skeletal system c. Major components that make up bone: c.i. Organic c.i.1. Collagen Type 1- most abundant protein found in our body. c.i.2. Glycosaminoglycans c.i.2.a. Glucosamine c.i.2.b. Chondrotin sulfate c.i.2.c. Supplements on the shelves contain these compounds to maintain joint integrity c.ii. Inorganic c.ii.1. Made of calcium and phosphate c.ii.1.a. Calcium is bound to phosphate to form calcium phosphate complex ( hydroxyapatite complex) c.ii.1.b. 98% of calcium and 80% of phosphate is found in out bones c.iii. Cells c.iii.1. Osteoblasts c.iii.1.a. Immature bone cells c.iii.1.b. Give rise to osteocytes c.iii.2. Osteocytes c.iii.2.a. Mature bone cells c.iii.2.b. Responsible for making new bone (bone builders) c.iii.3. Osteoclasts c.iii.3.a. Not truly derived from bone c.iii.3.b. Monocyte of white blood cell derived c.iii.3.c. Break down bone d. Resorption- term used for breaking down bone II. Major hormones involved in regulating bone break down a. Growth hormone a.i. Peaks in GH until it drops around age 40s a.ii. Implicated in longitudinal growth of long bones a.iii. Bones stop going at certain age- due to fusion of epiphyseal plate a.iii.1. Females 18 a.iii.2. Males 19 a.iv. Stimulates liver to produce IGF-1 a.iv.1. Induces action of growth hormone (protein synthesis) a.v. If you cannot produce growth hormone or IGF-1 a.v.1. Pituitary Dwarfism a.v.1.a. Easier to treat because you can give synthetic growth hormone a.v.1.b. Take gene for GH and put it into a bacteria (has circular DNA) and put under certain transcriptional factor control (promoter) grow in lab to high numbers. Pass through column with histadine gene. Produce insulin the same way a.v.2. Laron Dwarfism a.v.2.a. Lack of IGF-1 a.v.2.b. Discovered these processes by extracting genes from cadavers a.vi. Produce too much GH a.vi.1. Gigantism a.vi.1.a. Due to too much GH or IGF-1 production a.vi.1.b. Affect long bones and occurs before epiphyseal plates form a.vi.2. Acromegaly a.vi.2.a. increase in GF and IGF-1 after epiphyseal plate forms a.vi.2.b. increase in bone density a.vi.2.c. puts pressure on internal organs a.vi.2.d. many produce diabetes because GH induces glycogenolysis b. Parathyroid Hormone and Calcitonin b.i. Both control blood calcium levels ( normal 8.5-10.5 mg/dl) b.ii. Calcium is very important in physiological function b.ii.1. Muscle contraction b.ii.2. Second messenger cells b.ii.3. Membrane permeability b.ii.4. Blood coagulation b.ii.5. Cofactor for many enzymes b.ii.6. Neurotransmitter b.iii. Calcitonin b.iii.1. Decrease blood calcium level b.iii.2. Increase bone mineral density b.iv. Parathyroid hormone b.iv.1. Increase blood calcium levels b.iv.2. Decrease bone mineral density b.iv.3. When injected- has opposite effect by increasing bone mineral density and actually creating new bone tissue b.v. Problems as we age b.v.1. Become hypocalcitonin...
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This note was uploaded on 02/25/2012 for the course CHEM 1341 taught by Professor Compton during the Fall '08 term at Texas State.
- Fall '08