1. Life Span DevelopmentSpring 2010 Prenatal Development – Chapter 2 Birth and the Newborn Infant – Chapter 3

2. The Code of Life Humans begin life as a single cell. Our genetic code is stored and communicated in our Genes – the basic units of genetic information Genes are composed of sequences of DNA (deoxyriboneucleic acid). Our DNA determines the nature of every cell in the body and how it will function. Humans have over 25,000 genes Our genes are arranged in a specific order along 46 chromosomes (23 pairs). A chromosome is a very long DNA molecule and associated proteins that carry portions of the hereditary information of an organism.

3. Cells, Chromosomes, and DNA

4. Influence of Heredity on Development Cell Division: Mitosis and Meiosis Mitosis Genetic code carried into new cells Each chromosome splits and combines with chemicals to retake it’s original form, resulting in 2 identical copies of DNA Meiosis Process which forms games (sperm and ova), which have only 23 chromosomes Each pair of chromosomes split, one member of each moving into a new cell Fertilization Sperm and ovum cells provide 23 chromosomes each, to form 23 pairs 22 are autosomes 23rd pair are sex chromosomes X or Y chromosomes determine sex of child XX: female; XY: male

5. Mitosis

6. Multiple Births Monozygotic (MZ) Identical Twins Derive from a single zygote, which splits it two and develops into two individuals with the same genetic code. Rarer than DZ twins Dizygotic (DZ) Fraternal Twins Derive from two separate fertilized ova. Family background Chances of Bearing Twins Later in life Fertility Drugs

7. Dominant and Recessive Traits How do genes determine traits? Traits are determined by pairs of genes; consisting of two alleles Homozygous: two identical alleles Heterozygous: two different alleles Law of Dominance (Gregor Mendel) When a dominant allele is paired with a recessive allele, the dominant will determine trait expressed in the offspring 1 brown eyed allele and 1 blue eyed allele = brown eyed trait Recessive traits will be expressed only when two recessive alleles are paired 1 blue eyed allele and 1 blue eyed allele = blue eyed trait Carrier Person who carries & transmits recessive genes but doesn’t exhibit them

8. Chromosomal Abnormalities Chromosomal Abnormalities (More or less than 46 chromosomes) Down Syndrome Extra chromosome on 21st pair; resulting in 47 chromosomes Facial feature abnormalities; cardiovascular problems; cognitive, language, and motor development impairments. Sex Linked Chromosomal Abnormalities XYY Syndrome (Males with extra Y chromosome) Heightens secondary sex characteristics Klinefelter’s Syndrome (Males with extra X chromosome) Less testosterone; sex characteristic abnormalities; gynecomastia; infertility Turner Syndrome (Females with missing X chromosome) Lack estrogen; infertility; hindered development of ovaries and breasts. Triple X Syndrome (Females with extra X chromosome) Normal appearance; some cognitive deficiency; increased rate of infertility.

9. Genetic Abnormalities Phenylketonuria (PKU) Failure to metabolize amino acid phenylalanine causes CNS impairments. Cause of mental retardation Huntington’s Disease Fatal, progressive degenerative disorder; uncontrollable muscle movements Sickle-Cell Anemia Red blood cells are malformed and obstruct blood vessels. Can cause swollen joints, stroke, heart attack and kidney failure Cystic Fibrosis Most common fatal hereditary disease among European Americans Excessive production of thick mucus that clogs pancreas and lungs. Sex-Linked Genetic Abnormalities Hemophilia Disorder in which blood does not clot properly Carried by the X chromosome

10. Genetic Counseling and Prenatal Testing Genetic Counseling Advice concerning the probability that children will show genetic abnormalities Prenatal Testing Amniocentesis Need withdraws fetal cells from amniotic sac and examines them for genetic and chromosomal abnormalities Chorionic Villus Sampling (CVS) Syringe extracts villa from outer membrane of amniotic sac via vagina Ultrasound High frequency sound waves provide picture of the fetus Identify fetal position, multiple pregnancies, sex, growth, and structural abnormalities Blood Tests Can identify presence of recessive genes for a variety of disorders Alpha-fetoprotein Assay (AFP) blood tests

12. Conception Conception Union of sperm cell and ovum that occurs when chromosomes of each of these cells combine to form 23 new pairs Gametes fuse and form the zygote. Beginning of new human life The Ova Women have 400,000 ova at birth, which development via hormones At puberty, ova begin to mature and each month are released Enter fallopian tube and if not fertilized, are discharged with endometrium The Sperm Cells Sperm cells can contain X or Y sex chromosomes (Y swim faster) About 200 to 400 million sperm in each ejaculation; each of which has the possibility of fertilizing the ovum.

13. Conception The Journey to Conception Only 1 / 1000 sperm will ever arrive at the vicinity of the ovum Those that survive, reach fallopian tubes 60 – 90 minutes after ejaculation Some enter the wrong tube, others fail to make the final 2 inch journey Travel is not random – chemical secreted by ovum attracts sperm Fertilization Only one sperm will be able to fertilize the ovum Ova are surrounded by a layer called the zona pellucida Sperm secretes hyaluronidase, which opens the layer enabling penetration Once a sperm has entered, layer hardens Chromosomes for sperm and ovum line up to create 23 new pairs with a unique set of genetic instructions.

14. Female Reproductive Organs

15. Infertility 15% of couples suffer from infertility – the inability to conceive after 12-18 months of trying to become pregnant Infertility can be caused by a variety of factors: The age of the parents Previous use of birth control, illicit drugs, cigarettes, STDs Abnormally low sperm count in men The woman’s mother taking certain drugs during pregnancy Failure of the ovaries to release an egg – this can be caused by hormonal imbalance in the woman, damage to the fallopian tubes or uterus, or stress

16. Causes of Infertility In men: Low sperm count – most common problem Deformed sperm Low sperm motility Extensive athletic activity Infectious disease Direct trauma to testes In women: Irregular ovulation or failure to ovulate – most common problem Hormone irregularity, stress, malnutrition Various infections Inflammation of tissue Endometriosis: inflammation of endometrial tissue that is sloughed off into the abdomen rather than out of the body during menstruation Barriers or disorders in passageways Pelvic Inflammatory Disease

17. Methods to Help Infertile Couples Bear Children Artificial Insemination Sperm collected and frozen and injected into uterus at time of ovulation Low sperm count and motility In-Vitro Fertilization (IVF) Ripened ova are surgically removed and placed in lab dish with sperm Fertilized eggs are injected into others for implantation in the uterus Low sperm motility and blocked fallopian tubes Donor IVF Ovum harvested from another woman and implanted in mother Low or no ova production Surrogate Mothers Artificially inseminated with fathers sperm Mothers ova may be implanted Adoption

18. Pre-natal Development The Germinal Stage The Embryonic Stage The Fetal Stage

19. Stage 1: The Germinal Stage Germinal Stage of Pre-Natal Development From conception to implantation (0 to 2 weeks) What happens during the germinal stage? Cell division occurs Within 3 – 4 days, the zygote reaches the uterus After 1 week, the zygote begins to implant in uterine wall The process of implantation takes approximately 1 week What does the zygote look like? Blastocyst: mass takes on fluid filled ball of cells; cell differentiation Embryonic disk: Inner layers which become the embryo and later the fetus Trophoblast: Outer layers differentiate four different membranes Blood cell production, umbilical cord and placenta, amniotic sac, chorion

20. Stage 2: The Embryonic Stage Embryonic Stage of Pre-Natal Development From implantation to end of the first two months (3 to 8 weeks) What happens during the embryonic stage? Most vital organ and bodily systems begin to develop from the embryonic disk Development follows the Cephalocaudal and Proximodistal trends Endoderm (outer layer): nervous system, sensory organs, hair, outer skin Ectoderm (inner layer): digestive and respiratory systems, liver, pancreas Mesoderm (middle layer): excretory & circularity systems, bones, muscles Timeline of Development 3 weeks: head, blood vessels, and brain 4 weeks (Embryo weights only a fraction of an ounce and is ½ inch long) Heart begins to beat; arm and leg buds developed as well as eyes, ears, nose, mouth; umbilical cord beings to function 5 – 8 weeks (Embryo weighs 1/13 of an ounce and is one inch long) Hands, feet, fingers, and toes develop; kidney and liver function; bones

21. Stage 2: continued At 5 – 6 weeks, non-descript sex organs have formed Males and females possess a pair of undifferentiated gonads and two sets of primitive duct structures (Mullerian and Wolffian) Genetic Differentiation (7 weeks) Genetic activity on the Y chromosome causes testes to differentiate Ovaries differentiate if Y chromosome is absent At about 4 months, distinct external genital structures Effect of Hormones Androgens are necessary for the development of male sex organs Testosterone spurs differentiation of male duct system Low levels of androgen in females cause development of female sex organs Mullerian ducts develop into fallopian tubes, uterus, and vagina

22. Stage 2: Embryonic Stage

23. Stage 3: Fetal Stage Fetal Stage of Pre-Natal Development From third month to birth (9 weeks to birth Gains in size and weight and maturation of organ systems Timeline of Development 9 – 12 weeks (Fetus weighs one ounce and is 3 inches long): Major organ systems formed; eyes distinguishable; sex of fetus can be determined visually; responds to external stimulation. End of the Second Trimester (Fetus weighs 2 lbs and is 14 inches) Mother detects fetal movement; opens and shuts eyes; sucks thumb; sleep and wake cycle; responds to light and sound End of the Third Trimester (Fetus weighs 7 lbs and is 20 inches long) Heart and lungs increasingly able to sustain life; fatty layer develops under skin substantial gains in height and weight; fetus turns upside down Survival rate increases to 90% at end of the 7th month

24. Fetal Stage: Continued Fetal Perception End of 13th week: responds to sound waves Third trimester: can determine frequencies Research has found: Memory for prenatal vocalizations Preference for mother’s voice Gains in size and weight and maturation of organ systems Fetal Movement Middle of 4th month: detect first fetal movements (squirms) 29-30 weeks: vigorous kicking Activity slows before birth Research has found: Individual differences Prediction of post-birth activity and motor development

25. Environmental Influences - Nutrition Risks of Maternal Malnutrition Can lead to low birth weight, pre-maturity, retardation of brain development, cognitive, motor, and behavioral development problems Risks of being too slender: low birth rate Risks of being too obese: stillbirth and neural tube defects Expectant Mothers Require Protein; Vitamins A – E; Iron; Zinc; Calcium; Folic Acid, & Calories Supplements often recommended Expected Weight Gain Between 25 to 35 pounds ½ lb. per week during first half; 1 lb. per week during second half Sudden large gains or losses are undesirable

26. Environmental Issues – Drug Use Antibiotics Malformed bones; missing limbs; stillbirth; brain damage; deafness Hormones Cancer; masculinization of sex organs of female embryos Vitamins Blindness; mental retardation; hearth defects Heroine Low birth weight; pre-mature birth; toxemia Infant addition and mortality Behavioral, motor, and language deficits which are apparent into childhood

27. Drug use - continued Marijuana Tremors, startling, premature birth; birth defects; neurological problems Learning, memory, and behavioral deficits apparent into childhood Predisposes offspring to opiate addition Cocaine Stillbirth; low birth weight; birth defects Hyperactivity; delayed cognitive and language development; social problems Alcohol Fetal Alcohol Syndrome: Underdeveloped brains; facial abnormalities; mental retardation; hyperactivity; learning disabilities; academic and behavioral deficits Caffeine Increased risk of miscarriage and low birth weight Cigarettes Prematurity; low birth weight; fetal death; mental retardation; hyperactivity Second hand smoke and paternal smoking also dangerous

28. Environmental Influences – Environmental Hazards Lead Delayed cognitive and intellectual functioning; memory deficits Paternal exposure increases incidence of kidney tumors Mercury Mental retardation; neurological damage PCB Motor and intellectual deficiencies; decreased responsiveness Radiation Damage to organs (eyes), central nervous system, and skeleton Mental retardation and physical deformities Paternal exposure increases incidence of leukemia

29. Environmental Influences – Stress and Aging Maternal Stress Linked to secretion of hormones with pass through placenta Connected to complications during pregnancy and labor Connected to low preterm, low-birth weight, and irritable babies Parental Age Aging fathers produce abnormal sperm Ideal maternal age: 20s Teenage: high incidence of infant mortality and low birth weight Over 30: fertility declines; increased risk of chromosomal abnormalities and Downs Syndrome and stillborn and preterm babies

30. Birth and the Newborn Infant The Process of Birth Begins… Neonates – term used for newborns About 266 days after conception, a protein called corticotropin-releasing hormone (CRH) triggers the process of birth The hormone oxytocin is released from the mother’s pituitary – build-up of oxytocin begins periodic contractions

31. Countdown... Dropping or Lightening Head of fetus settles in pelvis Braxton-Hicks contractions First uterine contractions may be experienced as early as 6th month Blood spotting in vaginal secretions Day or so before labor Rush of amniotic fluid from vagina Occurs in 1 woman in 10 Other Signs Indigestion, diarrhea, backache, abdominal cramps Fetus Signals to the Mother Adrenal and pituitary glands secrete prostaglandins and oxytocin to stimulate labor contractions.

32. The First Stage Stage 1 Lasts from a few hours to more than a day Uterine contractions efface and dilate cervix Cervix must dilate 10cm (4 inches) Contractions increase in strength, frequency, and regularity Mother may be prepped for episiotomy Fetal monitoring Measure fetal heart rate and mother’s contractions Transition Cervix is nearly fully dilated Head of fetus moves into vagina (birth canal) Frequent and strong contractions

33. The Second Stage Stage 2 Begins when baby appears at birth canal; ends with birth May last few minutes to few hours Crowning Baby’s head begins to emerge from birth canal Episiotomy may be performed once crowning takes place Used to prevent tearing of mother Controversial and used less frequently Baby breathes on its own Once baby’s head emerges mucus is suctioned from the mouth Umbilical cord is clamped and severed Stump will fall off 7 – 10 days later Newborn may be removed Foot-printed; ID bracelet; drops are applied to eyes; Vitamin K injection

34. The Third Stage Stage 3 Also referred to as the placenta stage Lasts minutes to an hour or more Placenta separates from the wall of uterus and is expelled Bleeding is normal Uterus begins to shrink Obstetrician sews episiotomy, if performed The exact moment of birth occurs when the fetus passes through the vagina and emerges from the mother’s body

36. Methods of Childbirth Cesarean Section Delivered by abdominal surgery Typically performed when the baby is showing signs of distress Increase in Cesarean Sections Performedin US Mother’s small pelvis; weakness; or fatigue Baby is too large; in distress (use of fetal monitors) Bypass infections in birth canal from HIV or Herpes Reduce malpractice suits Control date / time of delivery Baby in breach position or transverse position Diversity of birthing options LDRP All-in-one Rooms Birthing suite in hospital equipped for uncomplicated birth Home Birth Can be fairly safe for healthy women with little risk of complications

37. Birth Problems Oxygen Deprivation Hypoxia - Prenatal oxygen deprivation Can impair development of central nervous system Leads to cognitive, motor, and psychological problems Anoxia - Oxygen deprived at birth Predicted problems in learning and memory Can cause health problems such as early-onset schizophrenia Potential Causes Maternal disorders; immaturity of respiratory system; accidents Umbilical cord squeezed during birthing process Fetal Monitoring Technology Can detect distress to signal need for Cesarean Section

38. Birth Problems Premature and/or Low Birth Weight Babies Premature or preterm baby Occurs before 37 weeks gestation (normal is 40 weeks) Low-birth-weight baby Weighs less than 5.5 pounds Small for date Low-birth-weight, although born at full term More likely to remain shorter and lighter preterm babies Risks of Low Birth Weight Babies born between 3 ¼ and 5 ½ lbs. are seven times more likely to die Poor neurological and cognitive functioning in school years Slow motor development Pre-school experience can foster cognitive and social development

39. Postmature babies: Postmature infants are babies who are still unborn due weeks past the mother’s due date This is a concern for several reasons: The blood supply from the placenta may become insufficient to nourish the fetus adequately. As a result, blood supply to the brain may be decreased and could lead to brain damage Labor becomes riskier for both mom and baby, as baby is likely to be larger and needs to fit through the birth canal Doctors will typically use drugs to induce labor or perform a C-section

40. The Postpartum Period Maternal Depression Depression is normal due to hormonal changes Postpartum depression (10 – 20% mothers) Begins one month after delivery and may linger for weeks/months Major depressive disorder with PP onset Sadness, apathy, worthlessness, changes in sleep and appetite Interaction of physiological and psychological factors Rare form includes psychotic features Baby may be at risk of maternal harm May profit from social support and psychotherapy

42. Newborns are often covered with fine, dark fuzz called lanugo

44. Animal studies showed that there is a critical period just after birth when the animals have a particular readiness to learn, or imprint, from other members of their species who are present

46. APGAR Scale

47. Characteristics of Neonates: Reflexes Reflexes Unlearned responses elicited by certain types of stimulation Some have survival value, while others seem to be evolutionary Neural functioning can be determined by testing reflex Reflexes demonstrated by neonates Rooting Reflex: turn head and mouth in direction of stroking of cheek Sucking Reflex: babies will suck object that touches the lips Moro (Startle) Reflex: back arches, legs and arms are flung out and then brought back toward chest into a hugging motion Grasping (Palmar) Reflex: babies grasp objects pressed against palms Stepping Reflex: babies will mimic walking when help upright Babinski Reflex: infant fans toes when feet are stroked Tonic-Neck Reflex: infant turns head to one side, extending arm and leg

48. Reflexes Rooting Reflex

49. Characteristics of Neonates: Sensory Capability Vision Visual acuity (sharpness) Estimate of 20/600 Best see objects 7 to 9 inches from eyes Lack peripheral vision of older child Able to track movement within one day of birth Visual accommodation Self-adjustments made by eye lens to bring objects into focus Neonates show little or no visual accommodation Convergence does not occur until 7 or 8 weeks Color Vision Cones less developed than rods at birth At 3 months, can see most visible colors Infants are not passive

50. Characteristics of Neonates: Sensory Capability Hearing Fetuses respond to sound Middle and inner ear mature in shape and size Neonates hear remarkably well Respond to sounds of different amplitude and pitch May play a role in attachment Show preference for mothers’ voice Pre-natal exposure to mothers voice and learning may play a role Responsive to sounds and rhythms of speech Show no preference for specific languages

51. Characteristics of Neonates: Sensory Capability Smell Well developed at birth Demonstrate facial expressions to different odors Aversion for noxious and preference for pleasant odors Recognize familiar odors Learned preference for mother Taste Sensitive to different tastes Demonstrate facial expressions to basic tastes Discriminate between salty, sour, and bitter tastes Prefer sweet tastes

52. Characteristics of Neonates: Sensory Capability Touch Sensitive to touch Touch elicits many reflex behaviors Provides comfort, security, and foundation for attachment Pain Less sensitive to pain than older babies Habituation Behavioral difference across ethic groups European American infants habituate slower than Chinese and Japanese American infants Show a decline in interest as a repeated stimulus becomes familiar Differences may be due to: Genetic endowment, pre-natal environment, parental behavior

53. Characteristics of Neonates: Patterns of Sleep Neonates spend about 16 hours per day in sleep Typical infants has six cycles of waking and sleeping Series of naps distributed throughout day and night Sleep through the night by 6 months to 1 year Six stages of sleep and wakefulness identified REM Sleep Brain waves similar to wakefulness; paradoxical sleep Neonates spend 50% time in REM sleep Decreases in percentage of REM 6 months – 30% Function of REM sleep Brain activity required for brain development Older children and adults are stimulated during wakefulness Neonates compensate by spending more time in REM sleep

54. Characteristics of Neonates: Crying Main cause of crying Pain and discomfort Universal, expressive and functional communication Expressive response to unpleasant feelings Stimulates caregiver response Distinct causes and patterns of cries Hunger, anger, pain Colic: sudden, loud, cries and flexing resulting from digestive tract pain Peaks of crying in late afternoon and early evening Pitch can provide information Crying produces physiological response in others Can be influenced by parental response Extinction

55. Characteristics of Neonates: Soothing Sucking serves as a built-in tranquilizer Decreases crying and agitated movements Pacifier, sweet solutions Soothing processes Pick baby up, patting, caressing, rocking them Speaking to them in low voice Try to find cause of distress Learning process Parents learn what works through trial and error Infants learn that crying is followed by an intervention Is crying reinforced? Maturation Crying tends to be replaced by less upsetting verbal requests

56. SIDS: Sudden Infant Death Syndrome Sudden Infant Death Syndrome – crib death Apparently healthy babies stop breathing during sleep Most common cause of death in infants between 1 and 12 months Most likely to occur between 2 and 5 months Period when reflexive behavior is weakening Causes of SIDS remains obscure, but risk factors include babies aged 2 to 4 months babies put to sleep on their stomach premature and low-birth-weight babies males lower SES African Americans babies of teenage mothers babies of mothers who smoked or used narcotics during pregnancy