Musculoskeletal system >>>> Osteoporosis causes
Osteoporosis causes.
Osteoporosis is a disease of the bone tissue of the skeleton. It is characterized by a decrease in the total mass of bone tissue, microdisorders in bone architecture. With the development of osteoporosis, the level of bone strength decreases, which increases the risk of bone fractures. The danger of the disease lies in the fact that fractures of the vertebrae and bones of the peripheral skeleton lead to disability and even death, and the diagnosis of the disease, as a rule, begins after the fractures.
To understand the causes of osteoporosis, it is necessary to take into account that bone strength depends on:
- on the level of bone mineralization,
- on the quality of bone tissue (its architecture),
- on the correctness of the course of metabolic processes in bone tissue,
- from accumulated damage to bone tissue.
Bone tissue has a unique property of regeneration - remodeling. allows maintaining the strength of bones, promotes healing of microfractures, regulates calcium metabolism. First, the cortical and cancellous part of the bone tissue undergoes lysis of osteoclasts (cells of the macrophage system), which can lyse up to 50 microns of bone per day. In these places there is resorption. Further, the formed lacunae are filled with osteoblasts (bone-forming bone cells), which form 1 micron of bone per day. The cortical and cancellous parts of the bone tissue are always in the process of development. In an adult, the amount of tissue subject to resorptionequal to the amount of new bone tissue. If resorption (resorption, disappearance of bone tissue) has occurred somewhere, the process of remodeling begins there. Thus, up to 2-10% of the skeleton is renewed during the year.
Control over bone mineralization is assigned to systemic hormones: parathyroid, vitamin D metabolites, calcitonin. Three organs are involved in the process: the intestines, bone tissue and kidneys. Hormones maintain a certain level of calcium ions in the blood serum and affect bone metabolism (suppressing or accelerating bone resorption). Parathyroid hormone regulates calcium metabolism. With an increase in the concentration of this hormone in the blood, there is an increase in the rate of resorption and a simultaneous increase in the absorption (absorption) of calcium in the intestine. Parathyroid hormone also indirectly influences the absorption of vitamin D in the intestine. Vitamin D, in turn, increases the absorption of calcium in the intestines.Calcitonin has the opposite effect on calcium metabolism - it lowers blood calcium levels and also inhibits (inhibits) bone resorption.
It is known that such cellular factors as cytokines contribute to the formation of skeletal bones. Some of them (growth factors) activate osteoblasts, accelerate the restoration of bone microstructures, other cytokines stimulate bone resorption (interleukins-1-6-11-17; tumor necrosis factors; interferon gamma, prostaglandins).
In addition to microbiological processes, some other factors affect the state of bone tissue:
- Genetic predisposition
- Gender (female at risk)
- Eating disorders (malnutrition, anorexia) and, as a result, low body weight
- Vitamin D hypovitaminosis
- Avitaminosis D
- Lack of calcium trace element in food
- Treatment with corticosteroids (inhibits calcium absorption)
- Late puberty
- Hypogonadism (inadequate androgen production)
- Reduced physical activity (due to other diseases, overweight, old age)
- High dynamic loads on the skeleton
- Endocrine system disorders (hormonal disruptions)
- Injury (fall, blows).
Studying the causes of osteoporosis makes it possible to develop methods for the prevention of osteoporosis, because it is much easier to prevent than to treat the disease "osteoporosis".
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