Factors Affecting Bone Growth

Question 1. Enumerate various methods of bone growth and discuss the factors affecting bone growth.
Answer.

Methods of Bone Growth

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According to Proffit’s

 

According to Moyer,

Factors Affecting Bone Growth

• Genetic factors: Genes play overall role in a growth of a person. Final outcome and growth depends on interaction between genetic potential and environmental factors.
• Nutrition: Poor nutrition at critical stages of life permanently alter the normal developmental pattern of bone.
  • Proper nutrition is necessary for normal postnatal growth.
  • Diet should include proteins, vitamins, minerals, etc.
  • Minerals such as calcium, magnesium, phosphorous, manganese, florides, etc. are essential for proper bone and tooth growth as well as maturation.
  • Vitamin A regulates activities of osteoclasts and osteoblasts, and deficiency of vitamin A may be associated with defective bone growth.
  • Vitamin D is required for normal bone growth along with calcium.
  • Malnutrition results in disordered growth.
  • If ill effects are not so severe, growth process accelerates when adequate nutrient is provided. This is known as “catching up” growth.
• Secular trends: In a large population changes in size and maturation is shown to occur with time. For example, l5 year old boys are 5 inches taller than the same age group some decades earlier. Such secular trend is due to improved socioeconomic status and improved diet.
• Psychological stress: Psychological stress can adversely affect growth by inhibiting hormone secretion. Psychological stress leads to retard in bone growth.
• Illness: Prolonged and debilitating illness can have an adverse effct on bone growth.
• Climate and seasonal effcts: Growth in height is faster in spring than in autumn, while weight increase occurs faster in autumn than in spring.
• Race: Race play a role in growth process. In American blacks eruption and calcifiation of teeth occur an earlier than American whites.
• Growth hormones and growth factors: Various endo-crinal hormones have some inflence on growth of bone.
  • Postnatal growth is affected by the circulating concentration of growth hormone, growth hormone releasing hormone and somatostatin.
  • All tissues respond to growth hormone and produce a proportional body growth that slows aftr puberty when secretion of the hormone decreases.
  • Lack or ab sence of growth hormone causes dwarfim, whereas its continued secretion produces gigantism.
  • Abnormal secretion of growth hormone after the epiphysis plates have fused, leads to acromegaly.
  • The hormones of thyroid gland, thyroxine and triiodothyronine stimulate metabolism and are important in the growth of bones and teeth.

Question 2. Compare longitudinal and cross­sectional method of growth studies.
Answer.