Ch. 5 First Two Years: Biosocial

Percentile

• a point on a ranking scale 0-100

• the 50th percentile is the midpoint; half the people in the population being studied rank higher and half rank lower

If a 12 month old weight is at the 30th percentile, that means that __% of 12 month old babies weigh the same or less and _____% weigh more

30, 70

If you are in the 5th percentile, that means that ____% are bigger than you

95

T or F? If you are in the 90th percentile for your age, that means that you are in the top 10%, The other 90% of kids were below you

T

Co-sleeping

• when two or more people sleep in the same room

• often used when caregivers and children sleep in the same room

What nations are more known or less known for co-sleeping?

More Known

• Asian and African

Less Known

• European and North American

Reasons for Co-sleeping

• poverty

  • separate bedrooms are a luxury

• culture

  • how many people believe that the baby has to sleep by themselves

• cohort

  • younger parents more likely to sleep with infants

• infant diet

  • more likely if breastfeeding

• adult response

  • can respond quickly to hungry or frightened baby

Reasons against Co-sleeping

• correlates with higher rates of sudden infant death

  • when child suddenly stops breathing

• baby gets accustomed, and sleep in parental bed long after infancy

• encourages independence

  • all depends on culture, some cultures have great need for independence, others don’t

Neurons

• one of billions of nerve cells in the CNS, especially in the brain

• at birth, has around 86 billion of these

• connected to other neurons through axons and dendrites

Axons

• transmit impulses from neuron to dendrites of other neurons

  • away from the cell body

Dendrites

• receives impulses transmitted from other neurons via their axons

  • toward the cell body

• most brain growth in infancy is increased in dendrites

Synapses

• the intersection between the axon of on neuron and the dendrites of other neurons

• critical communication links within the brain

• infancy is characterized by an overproduction of synapses, and the formation is heavily dependent on experience

• axons and dendrites don’t touch

Neurotransmitters

• brain chemical that carries info from the axon of a sending neuron to the dendrites of a receiving neuron

• stimulates other neurons

• carry info across synaptic gap to the dendrites of the receiving neuron and is aided by myelin

Myelin

• the coating on axons that speeds transmission of signals from one neuron to another

• increases over childhood and explains why infants are slow to react to something pleasurable or painful

Neuron Summary

• a neuron fires sending an impulse through the axon

• axon impulse goes into synapse

• synapse picked up by dendrites

• dendrites bring message to cell body and fire conveying message via axon to dendrites of other neurons

• myelination helps speed up this process

• most infant brain development requires new connections between one neuron and another as dendrites grow

Divisions of the brain

• hindbrain

• midbrain

• forebrain (cortex)

Hindbrain

• controls automatic responses

• ex. heartbeat, breathing, temperature, arousal

Midbrain

• affects emotion and memory

Forebrain (cortex)

• thinking, feeling, and sensing

• cortex is located here and about 70% of neurons are here

• has two halves and four lobes

Four Lobes of the Brain

• occipital

  • vision

• temporal

  • hearing

• parietal

  • smell, touch, and spatial understanding

• frontal

  • enables people to plan, imagine, coordinate, decide, and create

Prefrontal Lobe

• the area of the cortex at the very front of the brain that specializes in anticipation, planning, and impulse control

• immature at birth

  • why a baby won’t stop crying if you tell them to, they can’t decide

Limbic System

• the parts of the brain that interact to produce emotions

• includes amygdala, hypothalamus, and hippocampus

• crucial for emotions and motivation

Amygdala

• a tiny brain structure that registers emotions, particularly fear and anxiety

• present in infancy, but growth depends partly on early experience

• can cause nightmares or terrors

Hippocampus

• a brain structure that is a central processor of memory, especially memory for locations

• is next to amygdala and responds to it by summoning memory

• some places evoke comfort or fear, even when experiences that originated emotions are gone

Cortisol

• the primary stress hormone; fluctuations in the body’s cortisol level affect human emotions

• is produced by the hypothalamus which is responding to amygdala and hippocampus producing hormones

• damages cognition if too much stress on the baby

Pituitary

• gland in the brain that responds to a signal from the hypothalamus by producing many hormones, including those that regulate growth and that control other glands

• sends cortisol to the body

Necessary Stimulation

• infants need stimulation which encourages movement

  • sights and sounds

  • emotional expression

  • social interaction

• playing, allowing varied sensations, and encouraging movement is necessary for brain connections

• lack of stimulation stunts the brain

Shaken Baby Syndrome

• a life threatening injury that occurs when an infant is forcefully shaken back and forth, a motion that ruptures blood vessels in the brain and breaks neural connections

• can result in

  • death

  • lifelong intellectual impairment

Hearing

• develops during pregnancy

• most developed sense

• sound is perceived in temporal lobes of the brain

Seeing

• baby cannot see until it is born and starts out legally blind and is the least mature

• experience combines with maturation of visual cortex to allow perception

• infants see between 4 and 30 inches away

• needed for motor development

Binocular vision

• the ability to focus the two eyes in a coordinated manner in order to see one image

• newborns gain this ability because at first they use two eyes indepndently

• experience leads to binocular vision

• emerges at about 13 weeks (3 months of age)

• by 12 months infants are more attracted to people’s sights over salient object

Touch and Pain

• is acute in infants

• wrapping, rubbing, massaging or cradling soothes babies

• pain is connected to touch

  • some are unpleasant like poke or pinch

  • can also be due to digestive issues

Taste

• rapidly adapt

• babies appreciate what parents eat prenatally through amniotic fluid, breast milk, and spoonfuls at dinner

Gross motor skills

• physical capabilities involving large body movements, such as walking and jumping

• emerge directly from reflexes and proceed in a head-down and center-out direction

  • first control heads, to upper bodies, to finally legs and feet

  • sitting → crawling → walking

Gross motor milestones

• rolling from tummy to back - 6 months

• sit unsupported - 9 months

• pull up to stand - 12 months

• walking without holding on - 18 months

• running - 24 months

• climb up stairs - 23 months

• jump up - 30 months

Fine motor skills

• physical capabilities involving small body movements, especially of the hands and fingers, such as drawing and picking up a coin

• around 6 months babies can accurately reach, grab, and grasp any object

• finger skills improve at end of first year

fine motor milestones

• grasps rattle - 3-4 months

• reaches to hold object - 4.5-6 months

• thumb and finger grasp - 8-10 months

• stack two blocks - 15-21 months

• imitates drawing vertical line - 30-39 months

Nutrition and Breast Feeding

• starts with colostrum, a thick high-calorie fluid secreted by the breasts at birth

  • is nutrient rich milk and offers boost to immunity

• human milk more sterile

• allergies and asthma less common in breast fed

• can also do formula 

Malnutrition

• when a person does not consume enough food to sustain normal growth

• may result in stunting

  • being short for their age

• may result in wasting

  • being severely underweight for their age and height

Sudden Infant Death Syndrome (SIDS)

• a situation in which a seemingly healthy infant, usually between 2 and 6 months old, suddenly stops breathing and dies unexpectedly while asleep

• caused by sleeping on stomach

• recommended to sleep on back

Immunization

• process that stimulates body’s immune system by causing production of antibodies to defend against attack

• can be accomplished naturally (by having the disease), by injection, by drops that are swallowed, or nasal spray

• protects from complications including deafness, blindness, sterility

Herd Immunity

• the level of immunity necessary in a population in order to stop transmission of infectious diseases

• rate is usually above 90%, higher for very infectious disease

• some cannot be vaccinated, so the herd immunity protects them

• infants under 3 cannot receive vaccinations