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Principles of Physical Development. Cephalocaudal - development from head down. Structural Example. Cephalocaudal Development Functional Example. Principles of Physical Development. Proximodistal: development from inside out - PowerPoint PPT Presentation
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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