Principles of Physical Development• Cephalocaudal - development from head

down.

Structural Example

Cephalocaudal DevelopmentFunctional 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.

Male Secondary Sex Characteristics

• Pubic hair: appears about one year after the testes and the penis have started to increase in size

• Facial/body hair appear when the pubic hair has almost completed its growth.

• Muscles: increase markedly in size and strength.• Voice: changes begin after some pubic hair has appeared.

Voice breaks are common when maturing is rapid.• Heightened Emotions: Moodiness, sulkiness, temper

outbursts, anxiety and irritability. Testosterone can also trigger a marked increase in aggressive behavior.

Developmental Order - Males

Female Secondary Sex Characteristics

• Hips: become wider and rounder due to enlargement of the pelvic bone and development of subcutaneous fat.

• Breasts: shortly after the hips start to enlarge, the breasts begin to develop.

• Hair: pubic hair appears. Auxillary hair usually begins to appear after the first menstrual cycle.

• Voice: becomes fuller and more melodious. • Heightened Emotions: Moodiness, sulkiness, temper

outbursts and a tendency to cry at the slightest provocation These moods are especially common during the premenstrual and early menstrual periods.

Developmental Order - Females

Growth

• Early Adulthood– height remains constant– muscle tone/strength peaks in late teens/20s

Growth

• Middle Adulthood– loss of fat and collagen in skin tissues– aging spots– thinner,graying hair– lose 1/2 inch per decade in height, gain weight– bone density begins decreasing

Menopause

• Peri-menopause: transitional stage of two to ten years before complete cessation of the menstrual period (menopause). Age 35 to 50 years. – decreasing levels of estrogen

– irregular menstrual periods

• Menopause: when a woman has gone through 12 months without menstruation (age 50)– hot flashes, headaches, dizziness, heart palpitations,

joint pain, osteoporosis

Growth

• Later Adulthood– weight loss– osteoporosis– osteoarthritis

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 – visionTemporal lobe – speech/language and hearingParietal lobe – sensory motor processesFrontal 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

Lateral view of the human brain shown at one-third size at several stages of fetal development. Note the gradual emergence of gyri and sulci.

Photographs of Human Fetal Brain Development

Childhood• Synaptogenesis: most occurs through 2nd year of life

• 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

Adolescence

• Brain is full adult weight by age 16

• Continued myelination

Aging Brain

• Loss of neurons

• Diminished functioning in remaining neurons

• Changes in tissue surrounding neurons

• Declining levels of neurotransmitters

• Senile plaques

Brain Weight During Development and Aging

Chronic Brain Disorders

• Dementia: general loss of intellectual abilities

• Alzheimer's: brain atrophy; neurofibrillary tangles

Themes of Development

• Continuity vs. Discontinuity

• Early vs. Later Experiences

• Nature vs. Nurture

• Critical Periods