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Let’s start at the very be‐ginning…! How, over time, did we come to be who we are? From zygote to birth, development progresses in an orderly, though fragile, sequence. EQ 9.2 EQ
“Your most fortunate moment!” A single sperm cell (male) penetrates the outer coating of the egg (female) and fuses to form one fertilized cell.
Prenatal Development: Overview
Zygote – conception to 2 weeks Embryo – 2 weeks through 8 weeks Fetus – 9 weeks to birth Placenta Connects fetus to mother Brings oxygen and nutrients Takes away waste
Critical period A time during development when influences have major effect
Out of the 200 million sperm and 5000 eggs ‘you’ won the race!!
Teratogens Substances that can damage an embryo or fetus (drugs, chemicals,
alcohol) 4
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Prenatal Development Embryo at about 6 weeks.
A zygote is a fertilized cell with cells that become increasingly diverse. At about 14 days the zygote turns into an embryo (a and b).
Hi mommy and daddy!
Notice the large neural tube and the formation of the heart and other internal organs. The cells have organized into these early organs. Amazing!
Zygote
Embryo at 40 Days
Embryo at 45 Days
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Prenatal Development At 9 weeks, an embryo turns into a fetus (c and d). Whoa.
Fetus at 9 weeks
A baby at 12 weeks: notice the webbing on the fingers, with the digits still fused
12 weeks ‐ about 3 ounces 7
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14 weeks –
16 weeks – •Muscles lengthen and become organized.
•Five and a half inches tall and only six to 1- ounces in weight
•The mother will soon start feeling the first flutters of the unborn child kicking and moving.
•Eyebrows, •Eyebrows eyelashes and fine hair appear.
15 weeks – •The fetus has an adult's taste buds and may be able to savor the mother's meals. •Foods the mother eats can affect movement of the baby! (Hold off on the spices, mom!)
•The child can grasp with his hands, suck her thumb, kick, or even somersault. 9
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20 weeks – 7 months.
•The child can hear and recognize her mother's voice.
•Room is getting tight at this point! Mommy knows this well…
•Though still small and fragile, the baby is growing rapidly and could possibly survive if born at this stage (though, it’s rare).
•The baby is less able to move, squirms and pushes more than flutters and kicks.
•Fingernails and fingerprints appear. •Sex organs are visible.
•Most babies begin to get into a head down position getting ready for birth.
•Using an ultrasound device, the doctor can tell if the child is a girl or a boy. This is when we found out that we were having another boy! 11
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Birth at 38-42 weeks •40 weeks is normal gestation
Now let’s take a look at…
Hello mommy and daddy!!!
Motor development via the reflexes
g on •The babyy weighs average 7 lbs. and is 20 inches long.
Perceptual Abilities
•At birth the baby can see, hear, move and recognizes the voices of her parents or others who have been near the mother.
Cognitive Development
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Infant Reflexes
Infant Perceptual Abilities
Rooting
Vision Clear for 8‐10 inches Good vision by 6 months Depth perception Visual cliff research Other senses Ears are functional prior to birth Infants particularly tune in to human voices Taste and smell are fully functional
Baby turns its head toward something that brushes its cheek and
gropes around with mouth
Sucking Newborn’s tendency to suck on objects placed in the mouth N b ’ d k bj l d i h h
Swallowing Enables newborn babies to swallow liquids without choking
Grasping Close fist around anything placed in their hand
Stepping Stepping motions made by an infant when held upright
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Cognitive Development: The Developing Brain
Cognitive Development in the Newborn
The developing brain overproduces neurons overproduces neurons.
Researchers try to determine cognitive development by studying an infant’s ability to becoming habituated to objects over a period of time.
Peaking around 28 weeks, these neurons are pruned to 23 billion at the time of birth. It is believed that we then produce more, up to the point of pruning them (as p p p p g ( adults we have around 100 billion). The greatest neuronal spurt is in the frontal lobe enabling the individual to think rationally.
Infants pay more attention to new objects than habituated ones, which shows they are learning! 17
Maturation
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What is your earliest memory?
The development of the brain unfolds based on genetic instructions. • This causes bodily and mental functions to occur in sequence— standing before walking, babbling
How old were you? What was it?
b f lki ll d maturation. before talking, called
Maturation sets the basic course of development… experience adjusts it.
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Maturation and Infant Memory The earliest age of conscious memory is around 2½ ‐
3½ years (Bauer, 2002). So, do we have memory as infants? (remember…) A 5‐year‐old has a sense of self and an increased long‐
term memory, thus organization of memory is different from 3‐4 years. Does anyone remember when you realized “you” were the only “you” there would be? 21
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