IN INFANCY 2013 The McGrawHill Companies Inc All rights reserved Cephalocaudal The sequence in which the earliest growth always occurs at the topthe headwith physical growth and feature differentiation gradually working from top to bottom ID: 708542
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Slide1
Chapter 5
PHYSICAL DEVELOPMENT
IN INFANCY
© 2013 The McGraw-Hill Companies, Inc. All rights reserved.Slide2
Cephalocaudal:
The sequence in which the earliest growth always occurs at the top—the head—with physical growth and feature differentiation gradually working from top to bottom
Proximodistal: Growth starts at center of body and moves toward extremities
Patterns of GrowthSlide3
FIGURE 5.1 - CHANGES IN PROPORTIONS OF THE HUMAN BODY DURING GROWTHSlide4
Average North American newborn is 20 inches and 7½ pounds
Weight doubles at about 5 months; triples by first birthday
Height increase at least 50% in first year
Average 2-year-old
26 to 32 pounds and 32 to 35 inches tall
Growth rate considerably slower in second yearGrowth appears continuous but actually occurs in spurts
Height and WeightSlide5
The brain is the command center of organismExtensive growth in utero
and infancy
Brain of neonate weighs less than one pound
By first birthday, the brain triples in weight, reaching nearly 70% of adult weight
EEG shows brain activity spurt from
1½ to 2 years of ageBrain DevelopmentSlide6
Forebrain: The region of the brain that is farthest from the spinal cord and includes the cerebral cortex and several structures beneath it
Cerebral cortex: Tissue that covers the forebrain like a wrinkled cap and includes two halves, or hemispheres
Lateralization:
Specialization of function in one hemisphere of the cerebral cortex or the other
Mapping the BrainSlide7
FIGURE 5.3 - THE HUMAN BRAIN’S HEMISPHERESSlide8
WHAT ARE NEURONS?
Basic unit of nervous systemReceive and transmit messages
Neurons vary according to function and location, but all contain
Cell BodyDendrites
AxonNeurotransmittersSlide9
FIGURE 5.5 - THE NEURONSlide10
HOW DO NEURONS DEVELOP?
As child maturesAxons grow in length
Dendrites and axon terminals proliferate
Connection networks become more complexMyelin
Makes messages more efficientMyelination occurs with maturation
Inhibition of myelination results in diseaseMultiple sclerosisSlide11
Blooming and pruning
Synaptic overproduction peaks about 4 months after birth
Prefrontal cortex overproduction peaks about 3 year of age
Adult density achieved in adolescenceHeredity and environment affect timing
Brain DevelopmentSlide12
FIGURE 5.6 - THE DEVELOPMENT OF DENDRITIC SPREADINGSlide13
FIGURE 5.7 - SYNAPTIC DENSITY IN THE HUMAN BRAIN FROM INFANCY TO ADULTHOODSlide14
The brain demonstrates both flexibility
and resilienceNeuroscientists believe that what wires the brain is repeated experience
Neuroconstructivist view:
Biological processes and environmental conditions influence the brain’s developmentThe brain has plasticity and is context dependent
Brain development is closely linked with cognitive development
Early Experience and the BrainSlide15
Infants 0 to 2 years of age slept an average of 12.8 hours a dayWith a range of 9.7 to 15.9 hours
The most common infant sleep-related problem reported by parents is nighttime
waking Infant
nighttime waking problems have consistently been linked to excessive parental involvement in sleep-related interactions with their infant
SleepSlide16
The eyes flutter beneath closed lidsIn non-REM sleep, this type of eye movement does not occur and sleep is quieter
REM (Rapid Eye Movement) sleepSlide17
FIGURE 5.10 - DEVELOPMENTAL CHANGES IN REM AND NON-REM SLEEPSlide18
Culture and Sleeping Arrangements
Sharing bed common in many cultures
Crib/separate room common in U.S.
American Academy of Pediatrics discourages co-sleeping because of stress and SIDS risk
Shared SleepingSlide19
Infant stops breathing, usually during night, and dies without apparent cause
Highest cause of infant death in U.S.
Highest risk is 2 to 4 months of age
Prone position reduces riskLess common in bedroom with fan and infant who sleeps with pacifier
Sudden Infant Death Syndrome (SIDS)Slide20
Healthy infants needLoving, supportive feeding environment
50 calories per day per pound of weight
Breast milk (nature’s food)Gradual increase of chew-and-swallow
More fruits and vegetables, less junk foodDemand feeding becoming more popular
Poor dietary patterns can cause overweight
NutritionSlide21
Breast milk Fewer gastrointestinal infections
Lower respiratory tract infections
Reduces effects of asthma in first 3 monthsReduce risk of skin inflammation
May lessen likelihood of obesityLowers risk of childhood and adult diabetes
Less risk of experiencing SIDS
Claims of no link to allergy preventionClaims of no links to children’s cognitive development and cardiovascular system
Breast Versus Bottle FeedingSlide22
There is lower incidence of breast cancer in women who breast feed their infantsReduction in ovarian cancer in women who breast feed their infants
Small reduction in type 2 diabetes in women who breast feed their infants
EVALUATION OF BENEFITS FOR THE MOTHERSlide23
Early weaning can cause deficienciesInfants can develop:
Marasmus:
A wasting away of body tissues in the infant’s first year, caused by severe protein-calorie deficiency
Kwashiorkor:
A condition caused by a severe deficiency in
protein in which the child’s abdomen and feet become swollen with waterUsually appears between 1 to 3 years of age
Malnutrition in InfancySlide24
Immunization begins in infancyAccident prevention
Increased monitoring needed in infancy
Most common accidents in infancyAspiration of foreign objects
SuffocationFalls
PoisoningBurns
Motor vehicle accidents
HealthSlide25
Dynamic systems theory: The perspective on motor development that seeks to explain how motor skills are assembled for perceiving and acting
When infants are motivated to do something, they might create a new motor behavior
Mastering a motor skill requires the infant’s active efforts to coordinate several components of the skill
Dynamic Systems TheorySlide26
Built-in reactions to stimuli that govern the newborn’s movements, which are automatic and beyond the newborn’s controlRooting
Sucking
Moro
Babinski
Grasping
ReflexesSlide27
Milestones for large muscle activitiesDevelopment of posture
Learning to walk
First year milestones - walks easilyDevelopment in second year
Skilled and mobile: pull toys, climb stairsNatural exercise: walk quickly, run stiffly
Gross Motor SkillsSlide28
FIGURE 5.16 - MILESTONES IN GROSS MOTOR DEVELOPMENTSlide29
Motor skills that involve finely tuned movements
Finely tuned (coordinated) movements Perceptual-motor coupling necessary
Finger dexterity (thumb and forefinger)
Two types of grasps: Palmar and Pincer Wrists and hands turn and rotate more
Experience and exercise have impact
Fine Motor SkillsSlide30
SENSATION AND PERCEPTION
Sensation: Stimulation of the sense organs.Perception: Interpretation of that stimulation.
Process of integrating disjointed sensations into meaningful patterns through perception
Measuring Sensation/Perception
Habituation/Dishabituation
Head movement indicates some visionVisual preference method: Measuring the length of time they attend to different stimuli
Tracking - Applied to vision and hearingTechnology Slide31
VISION
Visual acuity at Birth
Estimate of 20/600
Best see objects 7 to 9 inches from eyesGreatest gains in visual acuity between birth and 6 months
By about 3 to 5 years of age, approximate adult levels
Neonates have poor peripheral vision30 degree angle; By 7 weeks increases to 45 degrees; By 6 months of age, equal to adult (90 degrees)
Able to track movement within one day of birthPreference for moving objectsSlide32
VISION
Visual accommodation
Self-adjustments made by eye lens to bring objects into focusNeonates show little or no visual accommodation
Focus on objects 7 to 9 inches away
ConvergenceDoes not occur until 7 or 8 weeks
Color perceptionAt birth, cones are less well developed than rodsFully
mature around 3 months (Distinguish between blue/green)By 4 months can distinguish between similar colors/huesSlide33
Figure 4.5
CONVERGENCE OF THE EYESSlide34
THE LOOKING CHAMBERSlide35
VISUAL PREFERENCES
Preferences
Moderately complexMovement
Contour
Infants prefer facesDiscriminate maternal and stranger faces
Prefer attractive facesPay most attention to edgesSlide36
Preferences for Visual Stimuli in
2-Month-OldsSlide37
MOVEMENTS OF 1- AND 2-MONTH-OLDSSlide38
DEPTH PERCEPTION
Depth Perception
Develops around 6 months (onset of crawling)
Research using the Visual CliffGibson and Walk (1960)
Heart-rate response to determine fear
Relationship between crawling and fear of heightsAvoidance of the cliff and infants’ postureSlide39Slide40
HEARING
Fetuses respond to sound
Can localize sound
Startled by loud noises
Neonates respond to amplitude and pitchShow preference for mothers’ voices
Responsive to sounds and rhythms of speechCapable of perceiving phonemes of other languages
Show no preference for specific languagesSlide41
HEARING
DeCasper & Spence (1986)
Newborns can remember and prefer a story read by mom during the last 6 weeks of pregnancy.
Exposed to 3 ½ hours of story.Slide42Slide43
DEVELOPMENT OF HEARING
By 1 month, infants perceive differences between similar speech
sounds
By 3½ months discriminate caregivers’ voices
Infants perceive most speech sounds present in world languages
By 10 to 12 months, lose capacity to discriminate sounds not found in native language By 6 months, they can detect high frequency sounds nearly as well as preschoolers.
By 6 months, they can appreciate distance.Slide44
SMELL AND TASTE
Smell
Well-developed at birthDemonstrate aversion for noxious and preference for pleasant odors
Vanilla and StrawberryRecognize familiar odors
Recognize mom by 6 days
TasteSensitive to different tastesDemonstrate facial expressions in response to tastes
Prefer sweet tastesSlide45
Facial Expressions Elicited by Sweet, Sour, and Bitter SolutionsSlide46
TOUCH AND PAIN
Touch
Sensitive to touchTouch elicits many reflex behaviors
PainPast belief that neonates are not sensitive to pain
Neonates not cognitively equipped to ruminate about pain
Conditionable – distress when confronted with situation that previously presented itself as painful