Bone Remodeling Affected by Osteoporosis-Free-Samples for Students

Question: Discuss about the Bone Remodeling Affected by Osteoporosis. Answer: Introduction Bone remodeling is a cyclical process in which the mature bone tissues are constantly replaced by the new bone tissues. The process of mature or old bone tissue removal is called bone resorption and the process of new bone tissue formation is called ossification (Long, 2012). However, due to osteoporosis the bone remodeling or the reformation of new bone tissues gets affected. While it must be kept within the homeostatic range to minimize the harmful effects of bone thinning. The factors that disrupt the bone remodeling include parathyroid hormone and thyroid hormone (Naylor Eastell, 2012). Discussion The removal of mature bone tissues is both inhibited and enhanced by the signals received from the other parts of the body and the whole process depends on the availability and deficiency of calcium. Parathyroid gland has calcium sensing membrane receptors that senses the level of calcium in the body fluids. When the level of calcium reduces in blood, the parathyroid gland gets stimulated which leads to the secretion of parathyroid hormone. Calcitonin on the other hand reduces the effect of the osteoclasts and inhibits its production. This results in decreased resorption of bone tissues by the osteoclasts (Del Fattore, Teti Rucci, 2012). When parathyroid hormone gets secreted by the parathyroid gland, this in turn increases the level of as well as the activity of osteoclasts. The presence of the osteoclasts before the secretion of parathyroid hormone leads to an increased number and activity of the osteoclasts, the effect of the increased levels of osteoclasts are seen as increased resorption of phosphate and calcium ions. High levels of calcium in blood reduces the release of parathyroid gland and in turn reduced activity of the osteoclasts. Whereas, vitamin D helps in the effective absorption of phosphate and calcium from the intestine. The effects of osteoporosis are evident when the bone tissue formation (resorption) outpaces the process of removal of mature bone tissues (ossification). Due to the effect of osteoporosis bones loses it density, and it becomes fragile and porous (Boyce et al., 2012). The harmful effects of osteoporosis are seen when the effects of osteoblasts in the bone tissue formation falls behind the increased effects of osteoclasts. In the normal and usual bone remodeling cycle, osteoblasts secrete calcium salts and collagen matrix which leads to the formation of new bone tissues. In the next process, the osteoblasts get calcified and its structure gets changed which later forms osteocytes. The levels of calcium in bones are controlled by the osteocytes. The osteocytes remain intact till it is broken down for resorption by the osteoclasts. Thus, due to an imbalance in the levels of calcium in blood, increases the parathyroid hormone and this in turn increases the secretion of osteoclasts. These osteoclasts later remove the phosphate and calcium ions from the bones, and when this process quickens up, results in osteoporosis (Kular et al, 2012). The process of bone formation and the increased resorption by the osteoclasts due to imbalances of calcium in the body is summarized and explained in a concept map Concept Map The concept map explains both the scenarios in which calcium levels drops and increases in blood. When the calcium levels drop, parathyroid hormone releases the parathyroid hormone which elicits the levels of osteoclasts. Osteoclasts then degrades the calcium in the bones which results and in osteoporosis. While, when the calcium is high is blood thyroid gland secretes calcitonin and it stimulates the deposition of calcium in blood. Thus, a homeostasis is maintained References Boyce, B. F., Rosenberg, E., de Papp, A. E., Duong, L. T. (2012). The osteoclast, bone remodelling and treatment of metabolic bone disease. European journal of clinical investigation, 42(12), 1332-1341. Del Fattore, A., Teti, A., Rucci, N. (2012). Bone cells and the mechanisms of bone remodelling. Frontiers in bioscience (Elite edition), 4, 2302-2321. Kular, J., Tickner, J., Chim, S. M., Xu, J. (2012). An overview of the regulation of bone remodelling at the cellular level. Clinical biochemistry, 45(12), 863-873. Long, F. (2012). Building strong bones: molecular regulation of the osteoblast lineage. Nature reviews Molecular cell biology, 13(1), 27-38. Naylor, K., Eastell, R. (2012). Bone turnover markers: use in osteoporosis. Nature Reviews Rheumatology, 8(7), 379-389.