CFD 1220 Lecture Notes - Lecture 34: Eye Strain, Malocclusion, Social Isolation
11 Nov 2016
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Document Summary
Physical growth continues at a slow, regular pace. Girls are slightly shorter and lighter than boys until about age 9, when this trend reverses. Lower portion of body is growing fastest. After age 8, girls accumulate fat at a faster rate. Shortest children are found in south america, asia, pacific islands, parts of africa. Tallest children are found in australia, northern and central europe, canada, united states. Factors accounting for physical size differences: heredity: evolutionary adaptations to particular climates, environment: availability or scarcity of food; control of infectious diseases. Ligaments are not yet firmly attached to bones, resulting in unusual flexibility. By age 12, all primary teeth have been replaced by permanent teeth. Malocclusion occurs in one-third of school-age children. Weight of the brain increases by 10%: white matter rises steadily, especially in prefrontal cortex, parietal lobes, and corpus callosum, gray matter peaks in middle childhood and then declines as result of synaptic pruning.
