Developmental psychology/Chapter 9/Growth, Nutrition, and Sex

Thanks to the growth of the muscles in the heart, we must talk about three major aspects of growth
 * 1) Puberty causes growth spurts - abrupt and fast growth of the body, weight takes place before height and the limbs grow before the torso. Genes, gender, exercise, and maturation affect the shape of a human being. For both girls and boys, the lungs and heart increase in size - allowing athletic abilities to improve through decreased pulse and increased blood pressure. Fractures may be common to young athletes because their height increases before bone mass increases. The hairline may be receding and skin may be oiler with acne adding on.
 * 2) Defencies takes place way too often with deficiencies in important minerals (iron, calcium, zinc, etc.). Menstruation decreases iron, causing anemia. Iron is needed for strength and boys may find themselves tired 24/7 if they don't take enough iron in them. One reason for poor nutrition intake is because one's poor body-image, which may lead to anorexia (BMI = <18), bulimia nervosa and binge eating (eating a bunch of food at a certain time and NOT releasing it). This may take place during conception and needs to be treated in adolescence by the parents.
 * 3) The private parts directly associated with conception/pregnancy [the ovaries, the uterus, the penis, and the testes] are known as primary sex characteristics. Maturation and function of the primary sex characteristics rapidly develop. Secondary sex characteristics are the development of body parts that do not play a direct role in conception (a man's beard, a woman's breasts). Hormones cause sexual thoughts to flourish but it is culture that ultimately decides where that goes (repression vs. acting on them).
 * 4) Although a teen's culture affects sex, their close friends are better judging tools to determine whether they're going to be active/inactive. Rates of early sexual intercourse, teen births/abortions, and no use of "protection" have greatly decreased over the decades, possibly because of increased sexual education/fear of STDs (ironically, STD rates have increased). An older teenage "majority" boy is most likely to have sex and low-self esteem increases the likelihood of early sex.
 * 5) "All of these examples demonstrate a universal experience (rising hormones) producing another universal experience (growth of primary and secondary sex characteristics) that is powerfully shaped by cohort, gender, and culture".