Influences on Physical Growth and Health Heredity and environmental factors play a crucial role in growth and health during early childhood. Essential Elements  Emotional well-being  Restful sleep  Good nutrition  Relative freedom from disease  Physical safety

Heredity and Hormones Children's physical size and rate of growth are related to those of their parents. Genes influence growth by controlling the production of hormones. The pituitary gland releases two hormones that induce growth. Growth hormone (GH) affects the development of body tissues except for the central nervous system and genitals. Thyroid-stimulating hormone (TSH) prompts the thyroid glad to release thyroxine which is necessary for brain development and for GH to have its full impact on body size.

Emotional Well-Being Preschoolers with very stressful home lives suffer more respiratory and intestinal illnesses and more unintentional injuries than others. Extreme emotional deprivation can interfere with the production of GH and lead to psychosocial dwarfism, a growth disorder that appears between ages Typical characteristics include very short stature, decreased GH secretion, immature skeletal age, and serious adjustment problems.

Sleep Habits and Problems During a child’s sleeping hours GH is released. Children who sleep well are able to play and learn better, children who don’t disrupt their parents’ sleep and can contribute to significant family stress. Sleeping declines from ages 2 to 6 by 1 to 2 hours. Most children waken during the night time from time, those who cannot return to sleep on their own may suffer from a sleeping disorder. Because young children have vivid imaginations and difficulty separating fantasy from realists nightmares are common. About 4 percent of children are frequent sleepwalkers. Sleep terrors affect 3 percent of young children. Children may scream, thrash, speak incoherently, show a sharp rise in heart rate and breathing and initially be unresponsive to parents’ attempts to comfort. Sleep disorders usually subside without treatment.

Nutrition Preschoolers eat well at one meal and barely touch their food at the next and can become picky eaters. Appetites decline because growth has slowed. Because they eat less they need a high-quality diet. Social environment influences young children’s food preferences They imitate the food choices and eating practices of people they admire, both adults and peers.

Infectious Disease Poor diet depresses the body’s immune system. Illness reduces appetite and limits the body’s ability to absorb foods, especially in children with intestinal infections. In industrialized nations, childhood diseases have declined dramatically over the past half- century, largely because of widespread immunization of infants and young children. Inability to pay for vaccines, parents with stressful daily lives fail to schedule vaccination appointments, and those without a primary care physician.

Childhood Injuries Unintentional injuries like auto collisions, pedestrian accidents, drownings, poisonings, firearm wounds, burns, falls, and swallowing of foreign objects are the leading causes of childhood mortality in industrialized nations. In North America nearly 40 percent of childhood deaths and 70 percent of adolescent deaths are due to injury. Boys are 1.5 times more likely to be injured than girls and to be more severe. Children with temperamental characteristics are also at a greater risk for injury.

Preventing Childhood Injuries Laws prevent many injuries by requiring care safety seats, child-resistant caps on medicine bottles, flameproof clothing, and fencing around backyard swimming pools. Communities can help by modifying their physical environment and provide inexpensive public transportation, covering playgrounds with protective surfaces and window guards for high rise apartments. A widespread media and information campaign can inform parents and children about safety issues.