PSL300H1 Lecture Notes - Lecture 4: Bone Pain, Stridor, Parafollicular Cell
Document Summary
3 hormones for controlling calcium: parathyroid hormone (pth, calcitriol (vitamin d3, calcitonin. Calcitonin decreases ca2+ in blood (tones it down: bones (storage, kidney (urination, control excretion, digestive tract (intestine, control absorption. 99% of calcium found in bone (extracellular matrix) 3 types of cells: osteoblasts (form bones, the top layer of bones, osteoclasts (breakdown bones, the inner layer of bones (used to be osteoblasts, osteocytes (maintain bones) Bone is dynamic: 100% turnover in infants, 18% turnover in adults! Take calcium from bone, into blood: also take phosphates into the blood as by-product, osteoblast expresses rankl (ligand, osteoclast precursor expresses rank receptor, rankl & rank binding, osteoclast precursor turns into osteoclasts. Osteoprotegerin (opg): blocks rank rankl binding (leads to fewer osteoclasts, therefore lower calcium concentration in the blood) Parathyroid gland (back of the thyroid: necessary for survival. Exquisitely sensitive to calcium concentration changes (demonstrates the necessity of calcium balance in body)
