Development Physical Cognitive Moral Social

Human Development: Major Issues Nature/Nurture Genes/Environment Continuity/Discontinuity Stage Theorists: Piaget, Kohlberg, Erikson Stability/Change Born Outgoing, Always Outgoing? Is our development influenced by genes/environment? Is our development continuous like an escalator or more characteristic of that of a ladder. Each rung marking certain developmental phenomenon. Are shy babies going to be shy all their lives?

Zygote (germinal) Embryo Fetus Prenatal Development 1 cell becomes billions! Zygote (germinal) Embryo Fetus A hoard of sperm cells surround an ovum. Up to 200 million sperm compete to penetrate the egg. (The egg is 85,000 times larger than sperm) As 1 sperm penetrates the egg’s jelly-like outer coating, a series of chemical events begins that will cause the sperm and egg to fuse into a single cell. That cell will subdivided again and again to emerge 9 months later as a 100 trillion cell human being Fewer than half of fertilized eggs survive. Zygote-conception to 2 weeks- Cells begin to specialize in structure and function. (I’m a brain cell, you’re a heart cell) Undergoes rapid cell division Embryo-2-8 weeks Fetus-9weeks-Birth- begins to look human.

Early Development Zygote moves from fallopian tubes to uterus Fertilization, the joining of the sperm and the egg in the fallopian tube to form a unique human being, occurs.  Forty-six chromosomes provide the blueprint for the embryo’s physical characteristics.  This picture (above) is a fertilized egg only thirty hours after conception.  Magnified here, it is no larger than the head of a pin.  Still rapidly dividing, the developing embryo, called a zygote at this stage, floats down from the fallopian tube and towards the uterus. 36 hours after conception

Teratogens Congenital Infections -HIV, Rubella, Syphilis -HIV, Rubella, Syphillis Chemicals, Drugs and Medications -Alcohol, Street Drugs, Cigarettes Physical Agents -X-Ray Maternal Factors -Maternal Diabetes Congenital Infections -HIV, Rubella, Syphilis Chemicals, Drugs and Medications -Alcohol, Street Drugs, Cigarettes Physical Agents -X-Ray General Features  Dosage and Threshold Effects:  A teratogen can cause an effect only after a certain level of exposure is reached. Timing:  The effect of teratogens depends upon the timing of exposure.  The first trimester of pregnancy is the critical period of organ and limb development in the fetus.  The fetal brain develops throughout pregnancy and can be affected at any time. Exposure to a teratogen during the two weeks following conception is unlikely to cause birth defects. Although teratogens may increase the risk for birth defects, they do not necessarily cause problems in all cases. 2-3% of all babies are born with some type of birth defect.  Exposure to a teratogen may increase this risk, but nothing can eliminate the risk. HIV: The biggest risk to the fetus is for transmission of the virus to fetus, not for birth defects or mental retardation.  Treatment during pregnancy can greatly reduce the risk to the baby. 25% transmission rate mother-child Rubella: The birth defects associated with congenital rubella syndrome include eye defects, hearing loss, heart defects, mental retardation, and growth retardation. Syphilis: Symptoms of congenital syphilis infection include prematurity, enlarged liver and spleen, anemia, jaundice, skin rash, mental retardation, blindness, and deafness. Half spontaneously abort. Alcohol: The features of fetal alcohol syndrome (FAS) occur in 30-40% of babies born to chronic alcoholics.  Another 50-70% of such babies may suffer from fetal alcohol effects (FAE), which is milder than FAS.  To be diagnosed with FAS a baby must have the following features: growth retardation; central nervous system problems; characteristic facial appearance (small head, flat facial profile, thin upper lip), other major birth defects (heart, gastrointestinal, etc) are possible Children with FAS have failure to thrive, mild to moderate mental retardation and behavior problems.  FAS is the most preventable cause of mental retardation. Cigarette Smoking:  Constant exposure to cigarette smoke decreases the amount of oxygen crossing the placenta and can lead to low birth weight and premature babies. Cocaine/Street Drugs: miscarriage, placental abruption, vascular defects (limb reduction) , in utero strokes , increased risk for SIDS infant drug withdrawal

Principles of Human Development Cephalocaudal = Head to Tail Proximodistal = Center Out Typically a neonates growth is generally referred to in terms of cephalocaudal or proximodistal patterns . The cephalocaudal pattern is where the greatest development takes place at the top of the body, i.e. the head, and physical development moves gradually downwards: e.g. neck, shoulders, trunk, etc. The proximodistal pattern of development is where growth starts at the center of the body and moves towards the extremities. An example of such a pattern is the early development of muscular control of the trunk and arms relative to the hands and fingers. Cephalocaudal Principle of Development: The upper portion of the body develops quicker than the lower part of the body Proximodistal Principle of Development: The middle part of the body develops quicker than the outer part of the body. In this photo, the one month old infant's head and trunk are larger in proportion to her legs and arms.

4 Weeks Menstrual Cycle Stops Day 21 Hearbeat Spinal Cord grows fast-tail like Week 4 Hormones produced by the embryo stop the mother’s menstrual cycle.   Week 5 The embryo’s tiny heart begins to beat by day twenty-one.  The brain has developed into 5 areas and some cranial nerves are visible.  Arm and leg buds are visible and the formation of the eyes, lips, and nose has begun.  The spinal cord grows faster than the rest of the body giving a tail like appearance which disappears as the embryo continues to grow.  The placenta begins to provide nourishment for the embryo.    4 Weeks

Major Organs Form Week 7 Facial Features Form Week 7 Major organs have all begun to form.  The embryo has developed its own blood type, unique from the mother’s.  Hair follicles and nipples form and knees and elbows are visible.  Facial features are also observable.  The eyes have a retina and lens.  The major muscle system is developed and the embryo is able to move.   Week 8 The embryo is reactive to its environment inside the amniotic sac where it swims and moves.  Hands and feet can be seen.  At the end of week 8, the embryonic period is over and the fetal stage begins.  Facial Features Form Embryo is reactive to environment Week 8

Weeks 9-12 Heart rate can be heard Face well formed, eyes close until 28th week Fetus can make a fist Weeks 9-12 The heart is almost completely developed and the heart rate can be heard on a Doppler machine at the doctor’s office.  Most major organs and tissues have developed and red blood cells are now produced in the liver.  The face is well formed and the eyes are almost fully developed.  The eyelids will close and not reopen until the 28th week.  Arms, hands, fingers, legs, feet, and toes are fully formed.  Nails and earlobes start to form and tooth buds develop in the gums.  Fetus can make a fist with its finger.  Testosterone (male sex hormone) is produced by the testes in male fetus.   

Suck, swallow, irregular breathing sounds 13-16 Weeks Brain more developed Fetus feels pain Suck, swallow, irregular breathing sounds Transparent skin Bones become harder Kicks and somersaults Weeks 13-16 The brain is fully developed and the fetus can suck, swallow, and make irregular breathing sounds.  Fetus can feel pain (New England Journal of Medicine).  Fetal skin is almost transparent.  Muscles tissue is lengthening and bones are becoming harder.    Liver and organs produce appropriate fluids.  Eyebrows and eyelashes appear and the fetus makes active movements including kicks and even somersaults. 

20 Weeks Quickening Recognize Mother’s voice “Quickening” (when the mother can feel the fetus moving) usually occurs around this time.  Finger and toenails appear.  Lanugo, a fine hair now covers the entire body.  The fetus can hear and recognize the mother’s voice.  Sex organs are visible on ultrasound devices.    Quickening Recognize Mother’s voice Lanugo Sex Organs visible on Ultra Sound Finger and Toe Nails Appear xx-female xy-male

24-28 Weeks Vernix Covers Skin Practice Breathing A protective waxy substance called Vernix covers the skin.  By birth, most of the vernix will be gone but any that is left is quickly absorbed.  Fetus has a hand and startle reflex.  Footprints and fingerprints are forming.  Fetus practices breathing by inhaling amniotic fluid into its developing lungs.  The Third Trimester Fetal Development Weeks 25 – 28  Rapid brain development occurs during this period and the nervous system is able to control some bodily functions.  The fetus’ eyelids now open and close.  At 25 weeks there is a 60% chance of survival if born.  The fetus is considered legally viable at 28 weeks and there is a 90% chance of survival if born at this point.    Vernix Covers Skin Practice Breathing Fetus has startle reflex Eyes Open/Close Prints are forming 90% survival rate

Weeks 29 – 32 Body Fat SLEEP! 95% Survival Rate Weeks 29 – 32 There is a rapid increase in the amount of body fat the fetus has. Rhythmic breathing occurs, but the lungs are not yet mature.  The fetus sleeps 90-95% of the day.  At this point there the survival rate is above 95% if the baby is born.    

38-40 Weeks Weeks 38 – 40  The fetus is considered full-term.  Lanugo is gone except on upper arms and shoulders.  Hair on the baby’s head is now coarser and thicker.  The lungs are mature.  The average weight of the baby at this point is seven and a half pounds.  At birth the placenta detaches from the uterus and the umbilical cord will be cut as the baby takes his first breaths of air.  Breathing will trigger changes in the heart and bypass arteries forcing all blood to now travel through the lungs.    Endoscopic Picture: .5 millimeters thick. Through the uterine wall. Pictured: Jack Stiles’ first day out of the womb. Notice the Joe Mauer side burns. His hair was very dark and curly at birth but now is blonde and straight.

9 Months in 4 Minutes - clip

Infancy: Physical Development Reflexes: born with many reflexes to help them survive Your newborn baby is an amazing creature. The many reflexes he or she is born with help transition them to life and learn what they need to survive. Here are some of these reflexes to help you get to know your baby better: Moro Reflex: When you fail to support or hold the neck and head, the arms of your baby will thrust outward and then seem to embrace them selves as their fingers curl. This reflex disappears at about 2 months of age. It is also known as the startle reflex. Palmar Grasp: When you touch the palm of your baby's hand, the fingers will curl around and cling to your finger or an object. This is a good reflex to take advantage of with other children, to allow the baby to "hold" their hand. This reflex also makes it difficult to obtain handprints until it disappears at about 6 months. Plantar Grasp: This reflex occurs when you stroke the sole of your baby's foot, his toes will spread open and the foot will turn slightly inward. It is also known as the Babinski reflex. This reflex is fun to watch. By the end of the first year this reflex is usually gone. Sucking: While you may not believe this to be reflexive, it is. This ensures that the baby will nurse on a breast or bottle to be fed and occurs when something is placed in the baby's mouth. It is slowly replaced by voluntary sucking around 2 months of age. Rooting Reflex: When you stroke your baby's cheek she will turn towards you, usually looking for food. This is very useful when learning to breastfeed your baby. This reflex is gone by about 4 months. You may also notice this occurs when the baby accidentally brushes her own face with her hands. It can sometimes be a source of frustration if your baby flails her arms during feedings. Stepping Reflex: If you take your baby and place his feet on a flat surface he will "walk" by placing one foot in front of the other. This isn't really walking and will disappear by about 4 months of age. Tonic Neck Reflex: This is also called the fencing reflex, because of the position the baby assumes. When you lay your baby on her back and her head turns to one side she will extend her arm and leg on that side while the opposite arm and leg bend, assuming a "fencing" position. This reflex is present only until about the 4th month. Swimming: If you were to put a baby under six months of age in water, they would move their arms and legs while holding their breath. This is why some families believe in swim training for very little babies. It is not recommended for you to test this reflex at home for obvious safety reasons. Babinski Reflex

Video’s of Infant Reflexes Swimming Reflex Diving Reflex Infant Reflexes Moro Reflex

Infancy: Physical Development Growth rate declines throughout infancy but is faster than during any other postnatal period. Neural pathways strengthened and weakened. Brain plasticity best when young Motor development = Nature + Nurture Maturation – biological readiness – motor skills emerge. Brain: At birth, we have most of the brain cells you will ever have, but lack neural connections (wild growth spurt in 1st 15 months) During infancy neural pathways are strengthened and weakened. Plasticity of brain is best when we are young, brain can reorganize for missing pieces. Motor Development: Nature and nurture play a role. Maturation and learning combine to determine skill development and replace reflexes. As muscles and nervous system mature, skill emerge.

Infancy: Motor Development LIFT HEAD ROLL OVER SIT PROPPED UP SIT WITHOUT SUPPORT BEGINS TO STAND WHILE HOLDING ON TO THINGS FOR SUPPORT BEGIN TO WALK WITH SUPPORT MOMENTARILY STAND ON OWN W/O SUPPORT STAND ALONE WITH MORE CONFIDENCE BEGIN WALKING W/O SUPPORT 2 months – able to lift head up on his own 3 months – can roll over 4 months – can sit propped up without falling over 6 months – is able to sit up without support 7 months – begins to stand while holding on to things for support 9 months – can begin to walk, still using support 10 months – is able to momentarily stand on her own without support 11 months – can stand alone with more confidence 12 months – begin walking alone without support 14 months – can walk backward without support 17 months – can walk up steps with little or no support

Baby at 1 year of age: Jack Stiles at his first birthday party.

Jack Stiles after his 1st birthday party Jack Stiles after his 1st birthday party. Notice the groggy expression and the change of clothing…..quite a party!!