Chapter 10 Normative development a pattern of development that is typical or average Physical Growth and Development o With advances in health and nutrition children are taller and heavier than kids 100 Test 4 Study Guide years ago o Almost 40 are overweight or at risk o Sexual maturity is occurring earlier o Normative Growth each year Earlier onset of puberty in girls On average school aged children in the US gain 5 7 pounds and grow 2 3 inches Puberty physical changes including sexual maturation that occur as children pass from childhood into adulthood Girls have more body fat while boys have more lean body mass per inch of height Earliest outward signs of puberty are the development of breast buds larche around age 10 5in girls and testicular enlargement in boys around age 11 5 Age of menstruation in girls menarche has dropped over time in a secular trend changes over generations Growth occurs in spurts rather than gradually Growth is most rapid at night while the child is lying down Lower half of the body grows fastest Body proportions changing Torso becomes slimmer Bones especially in arms and legs become longer and broader Center of gravity shifts to pelvis Children very flexible because ligaments not firmly attached to the bones Children lose their primary baby teeth Permanent teeth come in at about 4 per year Children s eyes are maturing in size and function Myopia or nearsightedness often develops between age 6 and More than 1 in 5 children has some kind of vision problem between Hormonal changes begin in the adrenal glands two small organs that sit on top adolescence ages 6 and 11 of the kidneys Hormones send signals to the hypothalamus a small cone like structure in the brain and the pituitary gland one of the chief glands responsible for regulating hormones in the body which are then sent to the gonads primary reproductive organs System of signaling takes about two years to become fully established o Obesity In 40 years the of 6 11 year olds who are overweight increased from 4 to 19 An additional 18 are at risk for being overweight In the US almost 40 25 million of children are either overweight or at risk The epidemic of being overweight can be traced to lifestyle changes Fast Food o Families today often rely on processed convenience foods o High fat snacks are everyday fare o In low income neighborhoods fresh fruits veggies and low fat dairy is rare Advertising o Average child sees 25 600 TV commercials each year o 22 of ads are for food primarily snacks breakfast foods and restaurants o 43 of ads are for sedentary activities such as TV shows movies games toys and hobbies School o Public schools provide breakfast and lunch to low income children with support from the USDA o Schools must meet minimal federal standards for nutrition AND serve food that children will eat o Healthier alternatives are expensive o Many schools have vending machines allowing students to buy food not on the school menu Neighborhoods and Communities o Children are transported to school they no longer walk or bike o Outdoor play is limited Alternatives TV and video games Physical Inactivity o Children who were less physically active between ages 9 and 12 were more likely to be overweight by the age of 12 o Two main difference between overweight and never overweight children Home environment Afterschool activities o Physical and Mental Health Consequences of Being Overweight TV encourages sitting and eating Health problems once seen only in adults are becoming more common in children such as diabetes high blood pressure and high cholesterol Overweight children are more likely to suffer from sleep apnea and asthma Overweight and risk for overweight increases with age Most overweight children remain that way into adulthood causing it to be seen as a chronic problem Extra pounds are a social and emotional hazard Children subject to teasing and more likely to be excluded from friendship groups Less self confidence in their athletic competency social skills and appearance Prone to internalizing problems such as depression and anxiety o Promising Interventions Programs to help children lose weight have not been very successful but several interventions have slowed the increase in BMI typically seen in middle childhood In one a nurse taught a curriculum focused on reducing consumption of soft drinks to elementary school kids Another intervention was designed to reduce the amount of time 3rd and 4th graders spent watching TV and playing video games After school programs that include opportunities for outdoor free play along with structures physical activities are another promising strategy Brain Development o The brain has reached 90 of its adult size by the time the child is 8 years old o Normative Changes Dendrites and axons the specialized connections between neurons are still growing branching and establishing new synapses in response to new experiences Myelin white fatty substance encasing axons also increases Competitive elimination process that strengthens synapses that are used regularly and prunes unused synapses to eliminate clutter accelerates the speed with which children can process information Synaptic pruning leads to increased lateralization the localization of function in one of the hemispheres of the brain Corpus callosum thickens improving communication between hemispheres Brain development typically follows a cyclical process that systematically moves around the cortex Starts with the longest neural connections in the prefrontal cortex Moves to the occipital lobe Gradually shifts to shorter and shorter connections in the prefrontal parietal and temporal areas After finishing in one hemisphere growth moves to the other hemisphere and works in reverse order Then it restarts wiring and rewiring networks to promote new learning MRI studies support this view of brain growth Brain growth in early childhood is concentrated in the front of the brain Move further back in middle childhood Growth of gray matter resembles a shape Although apoptosis the programmed dying of cells occurs in early childhood it plays no role in the thinning of gray matter Reductions of neurons in middle childhood are a result of competitive elimination Areas of change in middle childhood are those related to higher level thinking Frontal lobes involved in recognizing future consequences overriding unacceptable social responses and remembering emotional experiences Prefrontal cortex involved in higher order