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Lifespan Development: A Topical Approach_Ch 3_Physical Growth and Aging Across the Life Span

Terms in this set (121)

Height -
While they are in elementary school, children in the United States grow, on average, 2 to 3 inches a year. By the age of 11, the average height for girls is 4 feet, 10 inches and the average height for boys is slightly shorter at 4 feet, 9 1/2 inches. This is the only time during the life span when girls are, on average, taller than boys. This height difference reflects the slightly more rapid physical development of girls, who start their adolescent growth spurt around the age of 10.
Weight-
Weight gain follows a similar pattern. During middle childhood, both boys and girls gain around 5 to 7 pounds a year. Weight is also redistributed. As the rounded look of "baby fat" disappears, children's bodies become more muscular and their strength increases.
While they are in elementary school, children in the United States grow, on average, 2 to 3 inches a year.
By the age of 11, the average height for girls is 4 feet, 10 inches and the average height for boys is slightly shorter at 4 feet, 9 1/2 inches.
This is the only time during the life span when girls are, on average, taller than boys.
This height difference reflects the slightly more rapid physical development of girls, who start their adolescent growth spurt around the age of 10.
Weight-
Weight gain follows a similar pattern. During middle childhood, both boys and girls gain around 5 to 7 pounds a year.
Weight is also redistributed. As the rounded look of "baby fat" disappears, children's bodies become more muscular and their strength increases.
These average height and weight increases disguise significant individual differences, as anyone who has seen a line of fourth-graders walking down a school corridor has doubtless noticed. It is not unusual to see children of the same age who are six or seven inches apart in height.
Figure 3.12 Pruning Gray Matter
This three-dimensional view of the brain shows areas of gray matter that are pruned from the brain between adolescence and adulthood.
(Source: Sowell et al., 1999.)

Brain produces oversupply of gray matter during adolescence which is later pruned back at a rate of one to two percent per year .
Number of neurons (the cells of the nervous system) continue to grow.
Interconnections become richer and more complex.
Adolescent thinking becomes more sophisticated.
Myelination—the process in which nerve cells are insulated by a covering of fat cells—increases and continues to make the transmission of neural messages more efficient.
-Both the pruning process and increased myelination contribute to the growing cognitive abilities of
-Synaptic pruning: elimination of unused neurons that allows established neurons to build more elaborate communication networks with other neurons. Unlike most other aspects of growth, then, the development of the nervous system proceeds most effectively through the loss of cells.
--Neurons that do not become interconnected with other neurons as the infant's experience of the world increases become unnecessary.
--They eventually die out, increasing the efficiency of the nervous system.

-Myelin: Axons of neurons become coated with myelin, a fatty substance that, like the insulation on an electric wire, provides protection and speeds the transmission of nerve impulses.
--Contributes to increased weight of brain
--Even though many neurons are lost, the increasing size and complexity of the remaining ones contribute to impressive brain growth.
--A baby's brain triples its weight during his or her first 2 years of life, and it reaches more than three-quarters of its adult weight and size by the age of 2.
Difficulties in seeing
-Blindness (20/200 after correction)
-Partial sightedness (20/70 after correction)

Visual impairment happens when there is a problem with one or more parts of the eyes or the parts of the brain needed to process the images sent from the eyes.

Although many people think blindness means a person can't see at all, this isn't always true. Some children who are considered blind can still see a little light or shadows, but they can't see things clearly.
-Diabetes
-Macular degeneration (scarring in middle area of retina)
-Glaucoma (Your eyes are filled with a thin fluid called aqueous humor. The fluid is made in the back of the eye, where it then passes through to the front and drains through tiny holes called outflow channels. When something stops the flow of this fluid, pressure builds up inside the eye, causing problems with vision)
-Cataracts are cloudy spots in the eye's lens that block light and change vision. -Babies can be born with cataracts, but they usually affect older people and not kids. No one knows what causes them, although too much sunlight exposure over the years may cause cataracts to form at a younger age in adults.

Even if a person is not so impaired as to be legally blind, their visual problems may still seriously affect their schoolwork. For one thing, the legal criterion pertains solely to distance vision, while most educational tasks require close-up vision. In addition, the legal definition does not consider abilities in the perception of color, depth, and light—all of which might influence a student's educational success. About one student in a thousand requires special education services relating to a visual impairment.

The behaviors of children with CVI reflect their adaptive response to the characteristics of their condition
Children with CVI may experience a "crowding phenomenon" when looking at a picture: difficulty differentiating between background and foreground visual information.
Close viewing is common, to magnify the object or to reduce crowding.
Rapid horizontal head shaking or eye pressing is not common among children with CVI.
Overstimulation can result in fading behavior by the child, or in short visual attention span.
The ability of children with CVI to navigate through cluttered environments without bumping into anything could be attributed to "blind sight", a brain stem visual system.
Children are often able to see better when told what to look for ahead of time.
Children with CVI may use their peripheral vision when presented with a visual stimulus, appearing as if they are looking away from the target.
Some children look at an object momentarily and turn away as they reach for it.