Infancy: frfr

Physical Growth and Development

Overall Physical Growth

  • Birth Weight and length:

    • Normal weight range ~ 5lb 8oz to 8lb 13oz

    • Normal length range ~ 19.5 inches

    • Babies lose approx. 5% of body weight in first fews days

      • Normal adjustment to life outside womb- waste elimination, feeding

  • Physical proportions

    • Head-to-body ratio: head compromises 25% of total length at birth

  • Percentiles: 1-100

    • Failure to thrive: a child born in normal ranges fall below 20th percentile

      • Detection is key to medical intervention

  • Weight

    • At 4th months old, weight typically doubles

    • At one year, weight has tripled

    • By age 2, weight has quadrupled.

  • Length

    • Average length at 12 months ~ 28.5-30.5 inches

    • Average length at 24 months ~ 33.2-35.4 inches (CDC, 2010).

Brain Growth- The First Two Years

  • Growth

    • Physical size of brain increases

      • At birth, brain is 25% adult weight

      • At 2-years old, but 75%

  • Neural development

    • Most neurons are present at birth, not fully developed

    • Transient exuberance:period of prolific dendritic connections

    • Myenlination: myelin sheath (fatty cells) protects axons, speeds neural transmissions

  • Prefrontal Cortex

    • Least-developed portion of brain at birth; substantial growth

Motor Development

  • Reflexes are inborn

    • Some are necessary for survival

      • Rooting reflex, breathing, sucking reflex

    • Some signify health, development

      • Moro reflex, stepping reflex, palmar grasp

  • Motor development is orderly

    • Follows cephalocaudal (head-down) proximodistal (center-out) principles

  • Gross Motor Skills

    • Large Muscle groups

  • Fine Motor Skills

    • Small, coordinated muscle movements

      • Pinching, grasping

Motor and Sensory Development

  • Sensation & Perception

    • Sensation: interaction with sensory receptors

    • Perception: interpreting information sensed

  • Sensory Development

    • Sight least developed at birth

      • Newborns see ~8-16 inches in front of them

      • Preference for faces, unusual, interesting, exciting images

    • Hearing: most developed at birth

      • In the womb, babies know the sound of mother’s voice

    • Touch/pain

      • Physiological reactions indicate sensation of pain-circumcision

      • Touch- necessary and comforting

    • Taste/smell

      • Ability to distinguish flavors: sweet, salty, sour, bitter (prefer sweet tastes)

      • Identify mother’s smell easily

Nutrition

  • Breastfeeding- “breast is best”

    • Colostrum: “liquid gold,” nutrient-dense, first days of life

    • Breastmilk has irons, fats proteins, for proper development

    • Alternatives to breastfeeding

      • Formula feeding may be necessary in various conditions (mother doesn’t produce enough milk, adoptive or two-father family, mother has communicable disease, etc.)

  • Introducing solid foods

    • Start simple: one at a time is best, spaced days apart to ID allergies

  • Malnutrition and Clean Water Access

    • Kwashiorkor: “Displaced Child’s Disease” Lack of sufficient nutrition

    • Marasmus: Starvation from lack of calories'/protein

    • Milk anemia: Lack of iron from drinking cow’s milk in place of nutritious foods

    • Clean water makes clean formula

Sleep and Health

  • Infant sleep requirements

    • From 0-2 years, average 12.8 hrs/day

    • Newborns sleep 14-17 hrs

  • SIDS: many risk factors, many unknowns

  • Sudden Unexpected Infant Death (SUID): some identified causes

  • “Back to sleep”

    • Back-sleeping recommended for every sleep

    • No soft bedding, blankets, potential hazards

  • Co-sleeping

    • Benefit of skin-to-skin contact

    • Risk of child suffocation, increased risk w/parental drug/alcohol use

  • Sleep Schedules

    • Nighttime waking is common

    • Many infants sleep 6 hrs during night by 6 months

      • Not doing so does not indicate a serious problem, but individual differences

Vaccinations

  • Immunizations: the debate

    • Personal beliefs, opt-out program, religious beliefs

    • Need for community protection, prevents resurgence of diseases

  • Herd immunity

    • 90% of population is vaccinated, population is protected

  • Approx. 1 in 14 children isn’t vaccinated

  • Outbreaks

    • More frequent as fewer opt to vaccinate

Cognitive Development within toddlers and infants

  • Schemas: mental representations used to understand the world

    • Assimilation: modification of new information to fit into our existing schemas

    • Accommodation: reorganizing what we know to fit new information

  • Six stages of sensorimotor intelligence

    • Stage 1- Reflexes (birth-6 weeks)

    • Stage 2- Primary Circular Reactions (6 weeks-4 mo.)

    • Stage 3- Secondary Circular Reactions (4-8 mo.)

    • Stage 4- Coordination of secondary circular reactions (8-12 mo.)

    • Stage 5 - Tertiary Circular Reactions (12-18 mo.)

    • Stage 6 - Mental Representation (18-24 mo.)

  • Object Permanence

    • Knowledge something exists when out of sight (understanding ~8 mos)

Learning & Memory Abilities in Infants

  • Piaget underestimated infant memory ability

    • Lacking in language to express memory

    • Experiments: preferential looking

  • Infantile amnesia

    • Infants and toddlers form memories, remember them weeks, months later

    • Lack of memory years later

      • Encoding/retrieval failures

      • Older children, adults use linguistic retrieval methods

      • Misalignment between encoding and new memory organization