Principles of Physical Development Cephalocaudal - development from head down. Structural Example

Cephalocaudal Development Functional Example

Principles of Physical Development Proximodistal: development from inside out Mass-to-specific: gross motor skills (large muscles) develops first followed by fine motor (small muscles) skills

Growth Newborn: 20 inches long; 7 1/2 pounds 1 inch per month ½ adult height by age 2 double weight by 4 months, triple by 12 months Head Circumference Fontanels Ossification

Growth Adolescence Puberty growth spurt - age 9 for girls, 11 for boys Sexual maturation

Stages of Puberty Prepubescent Stage: no longer a child but not yet an adolescent. Secondary sex characteristics begin to appear, but the reproductive organs are not yet fully developed. Pubescent Stage : dividing line between childhood and adolescence. Signs of sexual maturity appear - the menstrual cycle in girls and the first nocturnal emissions in boys. Secondary sex characteristics continue to develop. Gametes are produced (not in the quantity/regularity of Fully mature sex organs). Postpubescent Stage: Secondary sex characteristics become well developed and sex organs begin to function in a mature manner.

Brain Development Human brain – most functional and best-organized 3 pounds of matter in universe. Part of Central Nervous System Controls voluntary and involuntary activities 2 Hemispheres with 4 lobes

Development of Brain

Brain

Lobes Occipital lobe – vision Temporal lobe – speech/language and hearing Parietal lobe – sensory motor processes Frontal lobe – critical thinking

Nervous System Development

The Birth and Growth of Neurons Most neurons formed halfway through gestation Virtually no synaptic connections – it is experience and interaction with the environment that forms the synaptic connections 83% of dendritic growth (connections between synapses) occurs after birth During childhood - no new neurons, but the brain is still developing (overhead of brain structures during infancy). -By 5th birthday- brain has achieved fully 90% of adult weight. -Myelination of neurons  throughout childhood. -Different areas of brain  become specialized. -Lateralization - left brain/ right brain differences/ hemispheric specialization. Originates during prenatal period (2/3 of all fetuses positioned with right ear out - right ear advantage  left hemisphere - language specialization).

Childhood Synaptogenesis Myelination Lateralization Triples in weight by age 3

Use it or lose it – Natural Selection of Brain Wiring Exposure to enriched environments with extra sensory and social stimulation enhances the connectivity of the synapses However, children and adolescents can lose up to 20 million per day when not stimulated