Osteoporosis And The Weakening Of Bones Over Time Biology Essay

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Osteoporosis is a disease that is known to weaken bones over a period of time. Due to the bones being weak and fragile there is an increased risk for fractured bones and/or broken bones. The fracture and/or break frequently occur in the hip, spine and wrist. Osteoporosis develops from the balance between old bone resorption and new bone reformation. Calcium and phosphate are imperative to help form normal bone formation; without sufficient intake of calcium, the bones may debilitate. This causes bones that are infirmed and capable of breaking easily. The deprivation of bone and bone mass usually occurs over an extended period of years. Bone mass can be measured, but it is expensive and is not the only factor affecting bone fragility. A fracture can occur before being diagnosis; this could possibly be an indication that the disease is in the advance stages and could cause grave damage.

The chief source of osteoporosis is the scantiness of certain hormones. Those hormones are as estrogen in women and androgen in men. Mostly elderly women-those 60 years of age and better-are more like to be diagnosed with the disease. This causation is a result of the lower levels of estrogen that these menopausal women experience. Other factors that contribute to bone loss in women 60 and over are the lack of calcium and vitamin D intake, not exercising, and other age-related changes.ity varies by

There are two main types of osteoporosis: primary osteoporosis and secondary osteoporosis. Primary osteoporosis or postmenopausal osteoporosis normally happens-in women who have reached menopause-when a vast decrease in the level of estrogen in the body occurs. Secondary osteoporosis is caused by another disorder or drug.

Primary osteoporosis is more than 95% cases of osteoporosis in women and more than 80% in men. Most primary cases of osteoporosis occur in postmenopausal women and in older men. It is during this phase that an increase in the resorption-a loss of bone substance-occurs. Postmenopausal, involutional, senile, and age-related osteoporosis have also been used to characterize this type of primary osteoporosis. (merck.com).

A known cause of osteoporosis is a lack of estrogen which is due to the rapid decrease of the hormone that occurs at menopause. The vast majority of men over the age 50 have higher estrogen levels than postmenopausal women, but those levels also deteriorates with age. It has been reported that both men and women with osteoporosis have low estrogen level. Low estrogen levels contribute to the boost of bone breakdown that results in rapid bone discomposure. Bone discomposure is more significant if calcium intake or vitamin D levels are low. Low vitamin D levels can cause calcium deficiency which increases the activity of the parathyroid glands (secreting parathyroid hormone), that stimulates bone breakdown. Bone production also decreases for unbeknownst reasons. (merck.com)

There are a numerous other components that enhances the risk of bone loss and the development of osteoporosis in women. These risk factors are probably consequential to men also. Individuals who have had one fracture as a result of osteoporosis are at a greater risk of having more such fractures. (merck.com )

Secondary osteoporosis generally occurs when there is an underlying disease, deficiency, or drug that cause the disease. Chronic kidney failure and hormonal disorders such as Cushing's disease, hyperparathyroidism, hyperthyroidism, hypogonadism, and diabetes mellitus are some known underlying causes of secondary osteoporosis. Some known drugs that may contribute to secondary osteoporosis are corticosteroids, barbiturates, and anticonvulsants. Smoking, consumption of alcohol, and caffeine are also other underlying risks of secondary osteoporosis. (merck.com)

Secondary osteoporosis is said to be a result of certain health related conditions or treatments that intercede with the accomplishment of peak bone mass and can also cause bone loss. During this stage, a higher rate of bone remodeling-or an increase in the amount of bone being remodeled-causes a higher proportion of bone loss. Due to menopause and the hormone imbalance it causes more women are more susceptible to osteoporosis than men.



Osteopenia is the thinning of bone mass before it is loss, as in osteoporosis. In this phase, the decrease in bone mass is considered severe but is consider a monumental factor in the development of osteoporosis. Osteopenia develops more commonly in people over the age of 50 who already have a lower than average bone density but do not have osteoporosis. To distinguish between osteopenia and osteoporosis, the bone mineral density (BMD) must be measured.

Bone mineral density is measured through Dual Energy X-ray Absorptiometry (DEXA). DEXA uses lower energy x-rays that exposes patient to less radiation than regular x-ray which can assess calcium levels in bone. DEXA produce a T-score that is compared to healthy individuals to determine a diagnosis.

What T-score means:

A T-score between +1 and -1 is normal bone density.

A T-score between -1 and -2.5 indicates low bone density or osteopenia.

A T-score of -2.5 or lower is a diagnosis of osteoporosis.

The lower a person's T-score, the lower the bone density. Nearly all BMD test have 1 SD difference in a T-score which equals a 10-15 percent decrease in bone density. (NOF.org)

Biomechanical Analysis

Biomechanics is defined as "the application of mechanical principles in the study of living organisms." Information from anatomy, physiology, math, physic, and engineering provides the make-up of biomechanics. There are subdivisions that help gives some understanding of the biomechanics principle. (thebook)

The strength of a bone can be determined as the susceptibility to fracture. However, there are many reasons as to why a bone may fracture therefore, several different biomechanical definitions of bone fragility could exist. A main function of bones is to carry loads. Fractures can result from loads exceed the bone strength. (Turner 2002)

The biomechanical definition of bone fragility involves three components: strength, brittleness and failure to work. These components can be derived from a biomechanical test in which a bone is loaded until it breaks. Bone strength is defined as the maximum force. While brittleness is defined as the maximum distance carried and failure to work is the amount of energy absorbed. Bone strength is also influenced by bone size, shape, and tissue quality. (Turner 2002)

Bone diseases can cause fragile bones and affect bone structure in different ways. Osteoporotic bones might fracture during normal daily activities such as opening a window or rising from a chair. These non-traumatic fractures result from significantly weak bone. Osteoporotic bones absorb very little energy before breaking therefore more susceptible to fracture. (Turner 2002)

The spine, hip, and wrist are most involved in carrying a load; therefore they are most likely to fracture. The spine is responsible for most of the load carrying.

Osteoporosis is a disease that manifests itself by a decrease of bone mass and structure. Both changes lead to a decrease in bone strength and, consequently, to increased fracture risk. Bone metabolism is regulated by hormones and biomechanical impulses. Biomechanical regulation is widely carried out by transferring strength onto bone. When there is only a limited amount of muscle mass, only a small amount of strength is exerted onto bone and the rate of deformity remains very low. This results in decrease of bone mass. When there is more muscle mass and increased strength is applied to the bone, the latter receives the signal to build more bone through increased deformation.

Exercise or other physical activity is most efficient means of helping to prevent osteoporosis. Both women and men will benefit in many ways by remaining physically active as they age. Exercise offers many advantages when prescribed properly. Some of the advantages include the inexpensiveness of the activity, always available, as well as the enjoyment that could be fostered if done wisely. In the majority of the cases the side-effects are beneficial: improved cardiovascular and respiratory function, increased muscular strength and endurance, greater flexibility, and better motor coordination and balance.

While a sedentary lifestyle-lifestyle in which there is little to no physical activity-has been deemed one of the risk factors for osteoporosis, it also results in a downward spiral in other physiological functions. The loss of strength and aerobic capacity in many elderly people leads to a decrease in activity and an inability to continue the type of activities that provide an adequate load-bearing stimulus to maintain bone mass. Much of this loss in strength and overall fitness can be reversed through a carefully planned and progressive exercise program.

Perhaps the most important contribution of an active lifestyle in preventing osteoporotic fractures will be a decrease in the incidence of falls by increasing muscular strength and improving balance and coordination.