A & P 171
Osmosis: Marissa, Jeremy, and Eleanor
Question on front of packet
Calcium helps to keep bones strong but just drinking milk doesn’t mean that you won’t get osteoporosis. You may be genetically inclined to get it even though you drink milk every day. There are also many other things that contribute to getting osteoporosis, like not eating enough calcium, doing steroids causes bones to become weak and look like sponges when looking at it under a microscope. Scenarios A,B, and C help to explain that it’s not just the calcium that can cause osteoporosis Scenario A:
1. The skeleton is a metabolically active organ that undergoes continuous remodeling throughout life. Bone remodeling involves the removal of mineralized bone by osteoclasts followed by formation of bone matrix through the osteoblasts that subsequently become mineralized. The remodeling cycle consists of three constructive phases resorption, during which osteoclasts digest bone; reversal, when mononuclear cells appear on bone surface; and formation, when osteoclasts lay down new bone until the reabsorbed bone is completely replaced. Bone remodeling serves to adjust bone architecture to meet changing mechanical needs and helps to repair micro damages in bone matrix preventing the accumulation of old bone. It also plays an important role in maintaining plasma calcium homeostasis. 2. Calcium is essential for maintaining the necessary level of bone to support the structures of the body. The body is constantly using calcium fir the heart, blood, muscles, and nerves. Calcium is also lost through normal bodily process such as waste and the shedding of hair, finger nails, sweat and skin. If a patient’s diet doesn’t include enough calcium to replace what it used, the body will take calcium away from the bone, which weakens them and makes them more likely to fracture. 3. Parathyroid hormone enhances as the release of calcium from large reservoirs contained in the bones. Bone resorption is the normal destruction of bone by osteoclasts; which are indirectly stimulated by PTH. Calcitonin, which is produced by your thyroid gland, serves to lower blood calcium levels. It counters the actions of the PTH. Calcitonin inhibits osteoclast function, slowing the breakdown of bone. By opposing the action of PTH on the kidneys it also increases excretion of calcium in the urine. A high level of calcitonin, which may be caused by a thyroid tumor generally doesn’t result in elevated blood calcium. 4. In osteoporosis, the osteoclast are breaking down bone faster than the osteoblasts are building it up – which results in bone porosity(they begin to look like sponge on a microscope level) which results in increased risk of fractures from stress and trauma. 5. In a ground breaking international study, which led partially from the Sahlgerska Academy, researchers have now succeeded in identifying a total of 56 genetic regions that control bone density in human beings. Fourteen of these genetic variants increase the risk of fractures, th study, which has been published in the world leading journal Nature Genetics had shown. “We can prove that women who have a large number of genetic variants associated with low bone density have up to a 56% higher risk of osteoporosis as compared with women who have a normal set-ups of the same genetic variants” comments Claes Ohlsson. The results have led to several findings in bone density that can be targets for new treatment methods and therapies. 6. Sex(male of female), Age, Race, Family history, frame size, sex hormones, thyroid hormones, other glands, low calcium intake, eating disorders, gastrointestinal surgery, steroids , prednisone, cortisone, medications, sedentary lifestyle, excessive alcohol consumption and tobacco use. 7. There are typically are no symptoms in the early stages of bone loss. But once bones have been weakened by osteoporosis, you may have signs and symptoms that include: back pain,...
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