Human growth and growing tall

Human growth and growing tall!

HUMAN GROWTH: The stature to which each of us grows is predetermined in our genes, as the racial differences between Pygmies and vatusis testify. Tall parents tend to produce tall offspring. And, the children of fat parents may be predisposed to obesity but these basic builds can be modulated by, and indeed depend on, endocrine and nutritional factors. The fact that modern human beings are taller than their ancestors of colonial or medieval times is attributable in part to better nutrition and medical care, and in part to “hybrid vigor” whereby people now marry out of their own cultures, nationalities, and races, thus mixing the gene pool. Growth hormone promotes growth during childhood and adolescence, but slackens off when maturity is attained. Too much growth hormone, as is secreted by pituitary tumors, induces gigantism, while too little causes dwarfism. The adolescent growth spurt is correlated with the surge of sex hormones secreted at the time of puberty. Not surprisingly, nutritional factors have profound effects on growth, especially in immature individuals. Prenatal malnutrition may interfere with cell proliferation in the developing brain, resulting in mental retardation. Underfed children grow more slowly than normal, but if refeeding is not delayed too long, they will exhibit catch-up growth with little or no stunting of adult height. Prenatal growth is also affected by intrauterine conditions not the least of which is crowding. Birth weights of twins are typically lower than those of singletons, and triplets are born smaller than twins. In such cases, catch-up growth may eventually erase earlier deficits. Human beings take longer to grow up than any other animal. This is correlated with our considerable longevity but has probably evolved as an adaptation to our higher intelligence. It takes many years to educate children to the cultures into which they were born. See also Adolescence; Aging; Cell; Embryology; Human; Growth Hormone; Plant Growth; Plant Hormones - Richard J. Goss

HUMAN GROWTH AND GROWING TALL

Human growth and growing tall!