CHAPTER 5: Physical Development and Health- Infancy and Toddlerhood

Physical Growth

grow faster in first 3 years (especially first months); at 1yo the baby is almost 3x birthweight

Nourishment

around 83% of moms breastfeed at first, after 6 months (recommended) decreases 25%

Breastfeeding

Best option for baby, most digestible, lower risk of allergy, protect against diarrhea/ ear/ respiratory infections (pneumonia), premature babies have special breast milk. EXCEPTION: when mom is HIV positive they can pass through breastmilk & other diseases can pass)

Breastfeeding timeline

Babies should ONLY have breastmilk for the first 6 months, no solids/ fruit juice, continue milk/ formula for a year before switching to whole milk (for the fats), lower SES moms who return to work interfere with feeding, leads to malnutrition, long-term effects, slow brain development.

Building the brain

Before birth and during childhood is critical for physical, cognitive and emotional development, brain growth spurt coincides with change in cognitive performance

Brain Cells and Growth

Brain grows fastest prenatally and right after birth; dramatic increase in birth weight through 2 yo (build 25-80% critical connections), brain produces more neurons and pathways that needed that will die out (prune/ die out)

Myelination

covering axons of nerve cells with fatty substance produced by glia cells (increase neural communication), important young children less than 2 get enough fat, 80% of myelination is completed by 5yo (slowly continues to 25)

Primitive Reflexes

Babies are born with them, help baby survive, tied to evolutionary past, their presence/ absence tells us how Childs nervous system is developing

Rooting Reflex

When babies cheek is stroked, turn toward that direction and open mouth (prepare for breastfeeding)

Grasping Reflex

When palm of babies hand is touched, make a fist and hold on (monkey’s hang on to mother)

Moro Reflex

When baby is dropped/ hears a loud noise/ looses support, extend arms, legs, fingers and toes (“break fall”)

Locomotor Reflexes

Babies born with, resemble voluntary movement, do not reappear until months after reflex dissapears

Crawling Reflex

Baby placed on stomach, move head, arms and legs in crawling motion

Walking Reflex

Baby head above a flat surface, move legs and feet like walking motion

Plasticity

the flexibility of the brain (especially in early life), early experiences good and bad have lasting effect on brain function, an enriched environment promotes cortical connections (rats: enriched v impoverished cages had more neural connections)

Touch and Pain Sensory Capacities

Used to believe newborns didn't feel pain, now we know they do and changed many practices (surgery, circumcision, ear piercing)

Smell Sensory Capacities

Prefer “good” smell- vanilla to “bad” smell-fish

Taste Sensory Capacities

Newborns can distinguish tastes and prefer sweet tastes

Hearing Sensory Capacities

Develop before birth, know mom/ dad voice (may be important for parent bonding), hearing is key to language development, a hearing impairment is identified asap (screened in first 3mo)

Vision Sensory Capacities

Least developed sense at birth (20/400), infant’s eyes focus best around 1ft away (person holding to their eyes distance), vision improves to 6mo (20/20)

Color Perception

2mo- red and green, 3mo add blue, 4mo add yellow (prefer red and blue- like adults)

Visual Preferences

Even less than 2 day old babies have preferences: curved lines over straight, complex patterns over simple, 3D over 2D, pictures of faces over other pictures, new sights over familiar ones

Motor Development

voluntary control over muscles follows the two principles of development which are hierarchical integration and differentiation. This process allows infants to achieve greater coordination and precision in their movements as they grow.

Denver Developmental Screening Test

Identify children who are not developing normal (1mo-6mo), measures gross motor skills (rolling over), fine motor skills (hold rattle), language and social development. Provides ages when 25% 50% 75% and 90% of kids can perform certain milestones (Children above 90th percentile are developmentally delayed/ have delays in 2 or more categories and may need special attention)

Hand Control

Follows systems of action= increase complex combinations of skills (4mo can grab rattle but not small objects, finger close against palm; 7-11 mo pincer like motion between forefinger and thumb to grab a small object like a cheerio)

Locomotion

Crawling, walking, getting from one place to another

Crawling

Not a milestone, babies go about it in different ways and some skip it entirely (sit to walk), still very important, around 6mo babies are able to move using some form of crawling, by 9-10 months can get around very well

Army Crawl

Pull body with arms and drags legs

Scooting

Pushing themselves with their legs while sitting

Bear Walk

All fours with straight legs

Rolling

With purpose

Setting Event

Sets the stage for other significant changes, now they are able to go and explore where they want to, crawling gives a child a whole new view of the world (when carried they pay little attention), now they understand near and far, socially/ emotionally able to move to mom and away from unwanted, gives baby self confidence

Walking

Around 1 year babies stand well on their own and walking soon follows

Haptic Perception

Ability to acquire info about objects by handling them, doesn’t develop until child develops enough eye-hand coordination to reach for objects (size, texture, weight, shape)

Depth Perception

Using the visual cliff studies researchers determined younger infants can perceive depth, HR slows, show interest and not fear, but an older, experienced crawling baby will not cross cliff to reach parent (sense danger), both innate and experience- ecological theory

Ecological Theory

locomotor development depends on the interaction of their changed physical characteristics and environment, babies bodies change as they grow for size and strength, this impacts how they interact with their environment (visual cliff, crawl/walk, down incline)

Esther Thelen’s Research on Dynamic System Theory

motor development is continuous and an interaction between baby and environment, walking reflex doesn’t disappear- babies legs get chubby and lack muscle strength, when put in water it reappears

Infant Mortality

Proportion of babies who die in first year of life (in US lowest ever, less than 1%), more than 2x higher for black/ Native American babies than white, Asian and Hispanic (unequal access to healthcare), largest factor for disparity: rate of preterm/ low-birth weight babies

Sudden infant death syndrome (SIDS)

Sudden, unexpected death of any infant under 1 yr whose death is unexpected after autopsy, most common 2-4mo, typically fall asleep and die (heartbreaking for parents), evidence to underlying biological defect (chemical receptors don’t respond to awaken baby when breathing too much stale air- CO2 builds up), at least 6 gene mutations affect SIDS, increase 2-3x when parents smoke before/ after pregnancy, sleep on stomach increase rates (recommended babies sleep on back- CO2 builds up when face down and under blanket- avoid soft mattress/ surface)

Immunization

Essential for health, decrease vaccine-preventable infectious diseases, In US 90% plus of toddlers under 3 have completed their recommended vaccinations

Shaken Baby Syndrome (SBS)

Form of maltreatment with kids under 2 (especially with infants), result in irreversible brain trauma, under-reported (20% die within first few days being shaken, the rest have learning disabilities, neurological injury, vision problems, or paralysis), crying baby is normal- doesn’t reflect caregiving ability