Chapter 11 - Physical Development in Middle Childhood Flashcards
Brain Development
By Age 6 the brain has reached 90% of its size
Brain weight increases by only 10% during middle childhood and adolescence
White matter increases (prefrontal cortex, parietal lobes, and corpus collosum) while gray matter (peaks then decreases)
Lateralization increases, specialization increases
Other brain changes may involve alterations in neurotransmitter activity (more selective activation leads to more efficient and flexible thinking.) and the increase in androgens experienced by children of both sexes at about age 7 or 8
Body Growth
By age six- weigh 45 pounds and are 3 ½ feet tall
Lower half grows faster
Growth norms are different around the world and in countries with large immigration populations
Long lean – hot climate, food is plentiful, few diseases
Short stocky – cold climate, food is scarce,
Ligaments are not firmly attached to bone which causes flexibility
malocclusion
A condition in which the upper and lower teeth do not meet properly
Secular trends in physical growth
Changes from one generation to the next
In industrialized nations – taller and heavier during childhood then evens out by adulthood – most likely due to a faster rate of physical development.
Common Health Problems
Children from economically advantaged homes are often at their healthiest in middle childhood
Good nutrition
Development of the immune system
Growth in lung size
For children of lower SES families, we’re more likely to see health issues
Nutrition
Due to increasing focus on play, friendships and new activities children spend less time at the table
Children like foods they have eaten repeatedly in the past
obesity
A greater than 20% increase over healthy body weight based on BMI
BMI over 85th percentile is overweight
95th percentile is obese
At risk for: high blood pressure, high cholesterol, respiratory abnormalities, and insulin resistance. Which can cause: heart disease, sleep and digestive disorders, cancer, diabetes, stroke, circulatory problems, and death.
Causes: heredity accounts for a tendency (overweight parents, twins), environment does the rest.
Parents who undermine children’s ability to regulate their own food intake.
Children form maladaptive eating habits: more responsive to external stimuli, and less to internal hunger cues, eat faster, chew less.
Insufficient sleep may increase chances of being overweight. (more time for eating, less energy to be active, disrupt regulation of hunger and metabolism.
Inactivity is both the consequence and cause of weight gain.
Combating it: family programs, rewarding children for giving up inactivity
Myopia
Myopia - nearsightedness; inability to see distant objects clearly
Nearly 25% of children experience myopia by the end of school years
By early adulthood, 60%
Genetic component
Early biological trauma, such as low birth weight
Experiences such as reading in dim light or sitting too close to the television
Increases with SES
Large amounts of time spent reading even in good light, or spent at computers
Changes that led to the obesity epidemic and ways to combat it
Changes that led to the obesity epidemic Availability of cheap commercial fat (palm oil) and sugar (high-fructose corn syrup) Portion supersizing Increasingly busy lives Declining rates of physical activity
ways to combat it
public education about healthy eating and physical activity
building parks and recreation centers
expanding affordable healthy foods in low income neighborhoods
mandatory posting of nutrition information
special taxes
incentives for schools and workplaces for promoting healthy life style
obesity-related medical coverage
Hearing
In middle childhood, the eustachian tube becomes longer, narrower, and more slanted, preventing fluid and bacteria from travelling as easily from the mouth to the ear as it could in earlier years. Otitis media becomes less frequent than it was in infancy and early childhood.
About 3-4% of the school-age population develop some hearing loss from repeated infections, though
This rate raises to as many as 20% for low-SES children
Malnutrition
Children in middle childhood often take little time to sit and eat at the table if their parents don’t make them
Children report feeling better and having better focus after eating healthy foods, and feeling more sluggish after unhealthy foods
Easy availability is a big factor with children of this age
It’s notable that even mild nutritional deficits can affect cognitive functioning
Among children from middle- to high-SES families, insufficient iron and folate predict slightly lower mental test performance
Poverty-stricken children are more likely to have diets more lacking, over a longer period of time
Obesity
Obesity - a greater-than-20-percent increase over healthy body weight, based on body mass index, a ratio of weight to height associated with body fat
Note that the BMI is not particularly useful for people who have a larger- or smaller-than-average bone structure or who are particularly muscular
Even developing countries are experiencing increased obesity rates
Populations are becoming more urbanized, and we see more sedentary activities and diets higher in meats and refined foods
In China, obesity was nearly nonexistent just a generation ago
Rates of overweight and obesity tend to increase with age
Over 80% of overweight children become overweight adults
In many cases, overweight children have overweight parents
The parents often do not believe their children have a weight problem
Only about 20% of obese children get treatment, in part because of parental attitudes
In adolescence, these children often use crash diets to try to lose weight, making matters worse for them
When obese children do receive treatment, long-term changes in body weight often occur
It’s important for these treatments to be family-based and to focus on changing behaviours
Weight loss by parents in these programs is often correlated with weight loss by their children
Children maintain this weight loss better than do adults, highlighting the importance of learning good habits early in life
Schools can also contribute to reduction in obesity by providing healthier food choices and ensuring physical activity
Risks of Obesity
Serious emotional and social difficulties in childhood
High blood pressure
High cholesterol
Respiratory abnormalities
Insulin resistance
Cancer
Type II diabetes, once seen almost exclusively in adults, in rising rapidly among overweight children
Childhood obesity has multiple contributors
Genetic tendency to gain weight easily Lack of knowledge about healthy diet A tendency to buy high-fat, low-cost foods Family stress, which can prompt overeating Not getting enough sleep Early undernourishment Parental use of junk food as rewards Parental control of diet
So obese children tend to
Respond more to external stimuli, and less to internal hunger cues
Eat faster, and chew their food less thoroughly
Be less physically active (and have parents who are less physically active)
Watch more TV