Physical Development

• Endocrine System: group of endocrine glands that secrete chemicals called hormones

• Pituitary Gland: master endocrine gland that produces growth hormone

• Thyroid Gland: also involved in growth• Ovaries and Testes: are endocrine glands

responsible for development of reproductive system prenatally and sexual development during adolescence

Brain Development

• Cerebral Cortex: largest structure of human brain; has two hemispheres

• Lobes: frontal, occipital, temporal and parietal

• Lateralization: specialization of the functions of the two hemispheres

• Plasticity: openness of brain cells to positive and negative environmental influences

Changes in Neurons

• Neuron: nerve cell that handles information processing

• Axon: carries signals away from cell body• Dendrites: carries signals toward cell body• Myelin sheath: layer of fat cells that encases

many axons• Terminal button: releases neurotransmitters

into synapses, or gaps between neuron’s fibers.

Influences on Early Physical Growth

• Sensitive period: Romanian orphanage studies• Heredity:

catch-up growth: physical growth that returns to a genetically determined path after being delayed by environmental factors

Nutrition: breast vs. bottle feeding

Malnutrition: marasmus and kwashiorkor

Principles of Growth

• Cephalocaudal: earliest growth always occurs at the top, the head

• Proximodistal: growth starts at center of body and moves toward extremities

• Orthogenetic: development starts globally and undifferentiated

Newborn Capabilities

• Reflex: unlearned and involuntary response to a stimulus

• Survival Reflexes: breathing, eye blink and sucking

• Primitive Reflexes: no apparent adaptive function

Physical Behavior

• Developmental Norm: age at which half of US infants master particular motor milestones

• Gross Motor Skills: involve large muscles and whole body or limb movements; mastered before fine motor skills

• Fine Motor Skills: involve precise movements of hands, fingers, feet or toes

Emergence of Motor Skills

• Dynamic Systems Approach: view of development as a self-organizing process; use sensory feedback to modify motor behavior in adaptive ways