KAAP220 Lecture Notes - Lecture 15: Medullary Cavity, Osteoid, Coagulation
23 Oct 2018
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Document Summary
Transmit forces along the shaft and have a rich blood supply. Mesenchymal (stem) cells that produce cells that differentiate into osteoblasts. Produce new bony matrix (osteogenesis or ossification) Then assists in depositing calcium salts to convert osteoid to bone. Become osteocytes once surrounded by bony matrix. Maintain protein and mineral content of surrounding matrix. Release acids and proteolytic enzymes to dissolve matrix and release stored minerals. Variety of physiological functions (muscle contraction, blood coagulation, nerve impulse generation) Concentration variation greater than 30-35% affects neuron and muscle function. Absorb calcium and phosphate under hormonal control. Osteoclasts stimulated to erode matrix, releasing stored calcium. Calcitriol effects enhanced and calcium absorption increased. Increased released of hormone calcitriol, stimulating calcium reabsorption in kidneys. Secreted from c cells in the thyroid gland. Osteoblasts use calcium to deposit new matrix. Varying levels of calcium and phosphate loss in urine under hormonal control. Osteoclast activity inhibited calcium deposited in bone matrix.
