What Causes Osteoporosis?
Bones are very dynamic and active tissues. They are constantly being remodeled, in
which bone gets deposited and removed on both the external and internal surfaces.
Bone remodeling is a two-pronged process, which involves bone deposition and bone
resorption. Bone deposition is executed by osteoblasts, the bone-forming cells. Bone
resorption is executed by osteoclasts, the bone-destroying cells. During this process,
calcium and phosphate ions are liberated from the bone and enter the tissue fluid and
bloodstream. In healthy young adults, total bone mass remains constant, which indicates
that the rates of bone deposition and bone resorption are relatively equal.
Bones are continually remodeled for two reasons: to maintain ionic calcium homeostasis
in the blood and to respond to mechanical stress exerted on bones. Calcium is extremely
important in many physiological processes: transmission of nerve impulses, muscle
contraction, blood coagulation, secretion by glands and nerve cells, and cell division.
When blood levels of calcium fall, the parathyroid glands release parathyroid hormone,
which stimulates osteoclast activity to resorb bone and release more calcium into the
blood. When blood calcium levels are high, calcitonin, a hormone produced by the
thyroid gland, is released. Calcitonin inhibits osteoclast activity and stimulates calcium
uptake and incorporation into bone matrix. Bones function primarily as the body’s reserve
of calcium to readily supply it as necessary to maintain the many metabolic and
physiologic activities.
Bones are also remodeled in response to the demands placed on them by mechanical
stress and gravity. A bone is stressed wherever weight is exerted on it or muscles pull on
it. It is remodeled to accommodate the newly experienced compressive and tensile
stresses. In addition, bones grow thicker in response to the forces experienced during
exercise and weight gain. Thus, in the absence of mechanical stress, bone tissue is lost.
There are two major factors that influence the risk of developing osteoporosis: the level
of bone mass achieved at skeletal maturity, which is the peak bone mass, and the rate at
which bone loss occurs in later years.
Prevention is the most effective method of dealing with osteoporosis. This can be
achieved by maximizing peak bone mass at skeletal maturity and reducing the rate of age
and menopause-related bone loss. Thus, the more bone mass available before bone
loss occurs, the less likely it will decrease to a level at which fractures occur. Bone mass
is continually acquired during the first 30 years of life, reaching its peak between the ages
of 30 to 35. After age 35, the rate of osteoclast activity outpaces the rate of osteoblast
activity. Thus, bone loss occurs faster than bone formation, which is what causes the
onset of osteoporosis.
Bones are very dynamic and active tissues. They are constantly being remodeled, in
which bone gets deposited and removed on both the external and internal surfaces.
Bone remodeling is a two-pronged process, which involves bone deposition and bone
resorption. Bone deposition is executed by osteoblasts, the bone-forming cells. Bone
resorption is executed by osteoclasts, the bone-destroying cells. During this process,
calcium and phosphate ions are liberated from the bone and enter the tissue fluid and
bloodstream. In healthy young adults, total bone mass remains constant, which indicates
that the rates of bone deposition and bone resorption are relatively equal.
Bones are continually remodeled for two reasons: to maintain ionic calcium homeostasis
in the blood and to respond to mechanical stress exerted on bones. Calcium is extremely
important in many physiological processes: transmission of nerve impulses, muscle
contraction, blood coagulation, secretion by glands and nerve cells, and cell division.
When blood levels of calcium fall, the parathyroid glands release parathyroid hormone,
which stimulates osteoclast activity to resorb bone and release more calcium into the
blood. When blood calcium levels are high, calcitonin, a hormone produced by the
thyroid gland, is released. Calcitonin inhibits osteoclast activity and stimulates calcium
uptake and incorporation into bone matrix. Bones function primarily as the body’s reserve
of calcium to readily supply it as necessary to maintain the many metabolic and
physiologic activities.
Bones are also remodeled in response to the demands placed on them by mechanical
stress and gravity. A bone is stressed wherever weight is exerted on it or muscles pull on
it. It is remodeled to accommodate the newly experienced compressive and tensile
stresses. In addition, bones grow thicker in response to the forces experienced during
exercise and weight gain. Thus, in the absence of mechanical stress, bone tissue is lost.
There are two major factors that influence the risk of developing osteoporosis: the level
of bone mass achieved at skeletal maturity, which is the peak bone mass, and the rate at
which bone loss occurs in later years.
Prevention is the most effective method of dealing with osteoporosis. This can be
achieved by maximizing peak bone mass at skeletal maturity and reducing the rate of age
and menopause-related bone loss. Thus, the more bone mass available before bone
loss occurs, the less likely it will decrease to a level at which fractures occur. Bone mass
is continually acquired during the first 30 years of life, reaching its peak between the ages
of 30 to 35. After age 35, the rate of osteoclast activity outpaces the rate of osteoblast
activity. Thus, bone loss occurs faster than bone formation, which is what causes the
onset of osteoporosis.
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Osteoporosis
Protect your bone at every age...
Live Well, Live Strong, Live Long
Protect your bone at every age...
Live Well, Live Strong, Live Long