Developmental Psychology
Chapter 5: Body, Brain, and Health
5.1 Building Blocks of Growth and Lifelong Health
LEARNING OBJECTIVES:
Associate key processes of the endocrine and nervous systems with important
aspects of growth and development.
Describe and provide an example of each of the three major principles of growth.
Articulate the main components of the life-span developmental model of health and
the value of adopting this sort of approach to understanding health.
Growth
Human growth and development is an incredibly complex process, infuenced by both
genetic and environmental factors. Which of these factors dominates at a given point of
time depends on the certain time and the certain kind of development.
Celiac disease is an inherited digestive problem in which gluten (the proteins found
in all wheat products) triggers an immune response that damages the small
intestine. This leads to the body being unable to absorb nutrients, which in turn
leads to malnutrition and to stunted growth.
Catch-up growth occurs after a period of malnutrition or illness, refecting the bodyys
struggle to get back on the growth course it is genetically programmed to follow.
The Endocrine System
The endocrine, or hormonal, system consists of a group of endocrine glands that secrete
chemicals called hormones directly into the bloodstream. Perhaps the most critical of the
endocrine glands is the pituitary gland, the so-called master gland located at the base of the
brain. Directly controlled by the hypothalamus of the brain, it triggers the release of
hormones form all other endocrine glands by sending hormonal messages to those glands.
Moreover, the pituitary produces growth hormone, which triggers the production of
specialized hormones that directly regulate growth. The thyroid gland also plays a key role
in physical growth and development and in the development of the nervous system. A
, pregnant woman with thyroid defciency can give birth to a child with intellectual problems.
Thyroid defciency during infancy can also lead to mental problems. Later in life, no mental
problems occur, but growth slows down.
In males, the testes secrete large quantities of testosterone and androgens (other male
hormones). These hormones stimulate the production of growth hormone, which in turn
triggers the adolescent growth spurt. Androgens are also responsible for the development
of the male sex organs and contribute to sexual motivation during adulthood.
In females, the ovaries produce large quantities of the primary female hormone, estrogen,
and of progesterone. These hormones have the same function of stimulating the production
of growth hormone, which in turn triggers the adolescent growth spurt. Estrogen is also
responsible for development of the breasts, pubic hair, and female sex organs and for the
control of menstrual cycles throughout a womanys reproductive years. Progesterone,
sometimes called the pregnancy hormone, orchestrates the bodily changes that allow
conception and then support a pregnancy.
