1. Chapter 5- The First Two Years: Biosocial Development Body Changes
Average weight: double the birthweight by month 4, triple it by age 1, much of it is fat
Average height: grow 14 inches from birth to age 2
These numbers are norms, an average measurement.

2. Body Changes
Body Size
Head-sparing- biological mechanism that protects the brain when malnutrition disrupts body growth.
The brain is the last part of the body to be damaged by malnutrition.
Percentile- point on a ranking scale of 0 to 100.
50th percentile is the midpoint with ½ the sample being higher and ½ lower.

3. Sleep Average newborn sleeps 16 hours per day
Specifics vary due to age, characteristics, and social environment
Ample sleep correlates with normal brain maturation, learning, emotional regulation, academic success and psychological adjustment

4. Sleep REM Sleep: Rapid eye movement sleep, dreaming, rapid brain waves
Slow-wave sleep: quiet sleep, increases at 3-4 months
Co-sleeping: custom of parents and children sleeping in same room, more common in Asia, Africa and Latin America than in Western cultures

5. Brain Development
Neuron- the billions of nerve cells in the central nervous system.
Cortex- the outer layers of the brain.
Axon- a fiber that extends from a neuron and transmits electrochemical impulses from that neuron to the dendrites of other neurons.

6. Brain Development
Dendrite- a fiber that extends from a neuron and receives electrochemical impulses transmitted from other neurons via their axons.
Synapse- the intersection between the axon of one neuron and the dendrites of other neurons.
Neurotransmitter- a brain chemical that carries information from the axon of a sending neuron to the dendrites of a receiving neuron.

7. Brain Development

8. Transient Exuberance
The great but temporary increase in the number of dendrites in an infant’s brain from birth to age 2
Enables neurons to connect and communicate with other neurons
This is followed by pruning where unused neurons and misconnected dendrites die

9. Stress and the Brain
If it produces too many stress hormones in infants, the brain will not be able to have normal stress responses.
Occurs in infants who are terrified and experience other forms of stress.
Can continue to occur when the infant is an adult

10. Necessary and Possible Experiences
Experience-related aspects of brain function:
Experience-expectant : require basic common experiences in to develop normally (i.e. people who love them)
Experience-dependent: these happen to some infants but not all, not necessary for brain function (i.e. language baby hears)

11. Brain Development
prefrontal cortex: the area for anticipation, planning, and impulse control
Shaken baby syndrome- a life-threatening injury occurring when an infant is forcefully shaken back and forth, rupturing blood vessels and breaking neural connections .
Self-righting- inborn drive to fix a developmental deficit
All people have self-righting impulses for physical and emotional imbalances.

12. Sensation and Movement
Sensation- The response of a sensory system (eyes, ears, skin, tongue, nose) when it detects a stimulus.
Perception- The mental processing of sensory information when the brain interprets a sensation.
Sensory development- typically precedes intellectual and motor development

13. Sensation and Movement
Hearing develops during the last trimester of pregnancy and is already quite acute at birth; the most advanced of the newborn’s senses.
Vision is the least mature sense at birth.
Newborns focus only on objects between 4 and 30 inches away.
Binocular vision, the ability to coordinate the two eyes to see one image, appears at 3 months.

14. Smelling, Tasting, and Touching
Function at birth and adapt to social world
Babies recognize each person’s smell and handling
Basic Infant Care differs by culture
Massage important in some cultures
Infant senses function to help babies join the human family

15. Sensation and Movement
Gross motor skills- Physical abilities involving large body movements, such as walking and jumping.
Fine motor skills- Physical abilities involving small body movements, especially of the hands and fingers, such as drawing and picking up a coin.

16. Gross Motor Skills

17. Ethnic Variations Gene differences in different ethnic groups
Cultural patterns of child rearing affect sensation, perception, and motor skills

18. Surviving in Good Health
About 10 billion babies were born worldwide
More than 2 billion died before age 5
Immunization has saved many people
The risks of diseases are far greater than the risk from immunization.

19. Surviving in Good Health

20. Surviving in Good Health

21. Surviving in Good Health
Nutrition
For every infant disease (including SIDS), breast-feeding reduces risk and malnutrition increases it.
Breastfed babies are less likely to develop allergies, asthma, obesity, and heart disease.
As the infant gets older, the composition of breast milk adjusts to the baby’s changing nutritional needs.

22. Malnutrition
Protein-calorie: when not enough food of any kind is consumed
Stunting: being too short for your age due to severe and chronic malnutrition
Wasting: being very underweight due to malnutrition

23. Malnutrition
Marasmus: severe malnutrition during infancy where child stops growing, tissues waste away and then usually dies
Kwashiorkor: disease of chronic malnutrition during childhood where child becomes more likely to get other diseases such as measles, diarrhea and influenza