Physiology 3120 Study Guide - Diaphysis, Distal Convoluted Tubule, Epiphyseal Plate
24 Sep 2014
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Document Summary
99% of body ca is stored in bones: bone also has 4% k, 35% na, 50% mg, 80% carbonate and 99% phosphate. Bone is 33% organic compounds (collagen) and 67% inorganic components (39% ca then other ions) Kidney maintains ca blood levels by hormonal regulation in the distal convoluted tubule. Ca is not secreted in the kidney so cannot tune gfr and has poor absorption in. Ca is stored in hydroxyapatite crystals to prevent large plasma ca changes. Hydroxyapatite crystal formation and dissolution does not require hormonal signals but the plasma ca does. Parathyroid hormone (pth) regulates levels of ca in the ec fluid volume: released from chief cells in thyroid to activates vitd. Calcitrol (vitd) affects absorption of ca in gi tract. Two types: endochondral ossification (more common), development via cartilage template, intramembranous ossification, without cartilage template. Bones are categorized by type of development/formation.
