Human Growth Stages
From infancy to adulthood, human growth and development is a fascinating process. Studies regarding the various stages of physical and mental growth have led to important scientific discoveries. Understanding the stages of growth plays a helpful role in parenting, medical treatment and everyday life.
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Identification
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Human growth is caused by cellular division. According to Doctor Paul Kaplowitz, chief of the Division of Endicronology at Virginia Commonwealth University School of Medicine, "children grow larger because the cells throughout their body enlarge and then divide to form two cells. Then each of those cells enlarges and divides again." This cell growth is stimulated by human growth hormone, which is secreted by the pituitary gland in the brain. This hormone stimulates increase in height, distribution of body fat and development of bones and muscles.
Types
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There are two types of human growth stages: physical and mental. Physical growth stages describe changes in body mass and bone development. A growth chart, for example, is a model of physical growth. During transition periods, changes in feeding and sleeping patterns are usually noticed. Mental growth and development is studied primarily by psychologists. Physical stages of human growth will always be accompanied by linguistic, emotional and social developments, and in order to truly understand the growth process, both of these are taken into account.
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Infancy and Childhood
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Human growth stages generally follow a pattern that corresponds with the subject's age. Erik Erikson, a psychologist who lived and worked throughout the twentieth century, outlined eight stages of human development.
The first stage is infancy, lasting from birth to eighteen months. During this stage, the baby develops rapidly from a completely dependent and helpless newborn to a (usually) walking and relatively autonomous toddler. In terms of physical development, this stage witnesses the most growth. The endocrine system in particular goes from barely functioning in the newborn, to being complete and active in the eighteen-month-old.
During the second stage, called Early Childhood (eighteen months to three years), witnesses significant changes in linguistic development. While the average 18-month -old can only say a handful of words, a three-year-old can form sentences.
The third stage, called Play Age (three to five years) involves further linguistic development, and by age five the average child knows about 2,000 words.
The School Age child (six to twelve years) continues to rapidly increase in height and weight, and at this age the strongest influences on the child change from the parents and immediate family to outside peer groups.
Puberty and Adolescence
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Puberty and adolescence usually last from ages 12-18. The teenager will go through some important biological changes (such as the menstrual cycle and breast development for girls, and voice deepening and increased body hair for males). Hormones are crucial at this stage, and the increased presence of estrogen and testosterone can result in behavioral changes.
Adulthood
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Once the body has gone through puberty, no significant cell growth occurs.Both women and men experience a decrease in estrogen and testosterone (respectively), and women usually enter menopause around the age of fifty. Erikson designates the three stages of adulthood as Young Adulthood (eighteen to thirty-five), Middle Adulthood (35-55 or 65), and Late Adulthood (55/65 to death).
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References
Resources
- Photo Credit Image by Flickr.com, courtesy of foundphotoslj
