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Life span chapter 3
- 1. Chapter 3 Prenatal Development and Birth PowerPoints developed by Jenni Fauchier Butchered by Professor Carney
- 3. The Course of Prenatal Development • Fertilization to birth • Prenatal development lasts approximately 266 days 3
- 4. Fertilization • Zygote • Egg & sperm fuse • Create a single cell • 23 unpaired chromosomes from egg & sperm • Form 1 set of 23 paired chromosomes • 1 chromosome of each pair • • mother’s egg father’s sperm • Each parent contributes 1/2 of offspring’s genetic material 4
- 5. Zygote 5
- 6. 6
- 7. The Germinal Period Egg goes from ovary through fallopian tube (uterine tube) 7
- 8. The Germinal Period • Creation of zygote (fertilized egg) • Mature human egg • • 23 chromosomes Mature human sperm • • 23 chromosomes Egg fertilized by sperm • Creates zygote • 46 chromosomes 8
- 9. • The Germinal Period Sperm race to egg • 1 wins…usually. • Makes way to egg by smell • Once sperm penetrates • Chemical released • Prevents other sperm from entering • 2 penetrate • Possible miscarriage 9
- 10. The Germinal Period • Blastocyst • inner layer of cells • develops into embryo 10
- 11. The Germinal Period • Trophoblast (like trophy) • outer layer of cells • nourishes embryo 11
- 12. The Germinal Period • Blastocyst • Inner mass of cells • Eventually develop into the embryo • Trophoblast • Outer layer of cells • Will provide nutrition & support for embryo • Implantation • Attachment of zygote to uterine wall • 10 - 14 days after conception 12
- 13. 2. The Embryonic Period 13
- 14. The Embryonic Period • 2 - 8 weeks after conception • Rate of cell differentiation intensifies • Begins as the blastocyst attaches to uterine wall • Every body part eventually develops from these 3 layers • endoderm = Internal body parts • ectoderm = Surface parts • mesoderm = Parts surrounding internal organs 14
- 15. 2. The Embryonic Period • We looked at cells of the zygote in the germinal period • Now: • Cells of the embryonic period 15
- 16. Embryo 3 Layers of Cells 16
- 17. • The mass of cells is an embryoPeriod The Embryonic • Organogenesis -- the process of organ formation during the first 2 mo’s of prenatal development • organs are especially vulnerable to environmental influences • Life-support systems for embryo develop rapidly 17
- 18. The Fetal Period • Fetal period begins 2 mo’s after conception & lasts for 7 mo’s • 3 mo.'s after conception • Fetus 3” long; weighs 3 ounces • At birth, average American baby: • 7 ½ lbs & 20” long 18
- 19. • Don’t let them fool you….nothing works to stop the excruciating pain! • It was all invented by a man! 19
- 20. The Course of Prenatal Development The Brain • At birth – 100 billion neurons • Basic architecture assembled • 1st 2 trimesters • Neural tube: first 18–24 days • Forms the spinal cord • Neural Tube Defects • Effect so severe, won’t show you • Defect tied to nutrition 20
- 23. Hazards to Prenatal Development Some General Principles • Teratogen • Any agent that causes a birth defect • Severity & type of defect affected by • • • Dose Genetic susceptibility Time of exposure 23
- 24. Some General Principles • All drugs (prescribed, illegal) can have effects on unborn fetus • Antibiotics, analgesics, asthma medications • 1961: thalidomide tragedy 24
- 26. 26
- 27. Hazards to Prenatal Development Psychoactive Drugs • Psychoactive drugs • Act on nervous system & change moods • Alter states of conscious, modify perceptions • Extent of risk & harm varies 27
- 28. Your Doctor Wants You to Smoke 1951 28
- 29. Nicotine (March of Dimes longitudinal study, 2011) • – Heart defects – Absence or severe underdevelopment of hands, feet, radius, tibia, ulna or fibula – Missing fused or extra fingers or toes – Clubfoot – Cleft lip or palate – Eye defects – Gastrointestinal defects • Baby more likely • 2 or more defects 29
- 30. Teratogens and Timing of Their Effects on Prenatal Development Zygote 1 2 Most serious damage from teratogens in first 2–8 weeks Embryonic period (wks) 3 4 5 6 7 8 Central nervous system Heart Arms Eyes Legs Ears Period of susceptibility to structural defects Period of susceptibility to functional defects Fig. 3.7 (modified) Fetal Period (wks) 9 16 32 38 Teeth Palate External genitalia 30
- 31. Hazards to Prenatal Development Maternal Diseases • Diseases & infections cross placenta barrier • Rubella (German measles) • Diabetes • Sexually transmitted infections • Syphilis, Genital herpes • AIDS, HIV infection • New medications & vaccines available 31
- 32. Hazards to Prenatal Development Other Maternal Factors • Maternal diet, nutrition, & weight • Folic acid & iron • Fish: PCBs & mercury levels • Maternal age • Highest risks: adolescents, over 35 years • Down syndrome • Maternal emotional states 32
- 33. Hazards to Prenatal Development Parental Factors • Paternal factors • Father’s diet & low vitamin C • Drug use effects on sperm • Smoking – effects of second-hand smoke • Father’s age at conception • Birth defects: dwarfism, Marfan’s Syndrome 33
- 34. Hazards to Prenatal Development Environmental Hazards • Father’s exposure to lead, radiation • X-ray radiation • Pollutants & toxin wastes • Fertilizers & pesticides • Lead-based paints • Petrochemicals 34 • Why father’s exposure causes harm?
- 35. Cephalocaudal • Cap • Growth starts at the top & moves downward.
- 36. Patterns of Growth • 1. Cephalocaudal (Physical growth) • Sequence in which earliest growth always occurs at top, beginning with head • Physical growth • Brain & eyes grow faster than jaw • Differentiation of features
- 37. Proximodistal • Penis • Sorry, all I could think of. • Proximodistal • Growth starts at center & moves outward
- 38. Patterns of Growth • Proximodistal (Sensory & motor development) • Sequence in which growth starts at center of body & moves toward extremities • Sensory & motor development • Control muscles of trunk & arms before hands
- 39. Age 1 to 2 Years • 2 years • • • • • @ 26 - 32 lbs. Gain ¼ - ½ lb. per mo. @ 1/5 adult weight Average infant is 32 - 35“ tall @ 1/2 of eventual adult height
- 41. Shaken Baby Syndrome • Blindness • Majority • Neurological or mental disability • Cerebral Palsy • Mental retardation
- 42. Neuron
- 44. Neurons • Axon • Carries signals away from cell body • Dendrites • Carry signals toward cell body
- 45. Neurons • Myelin sheath • Layer of fat cells • Provides insulation • Helps electrical signals travel faster down axon
- 46. Neurons • Terminal buttons • Release neurotransmitters into synapses • Synapses • Tiny gaps between neurons' fibers • Born with 100 billion neurons
- 47. Synapse
- 49. Changes in Brain Regions • 1st yr.'s of life • Neurons change in 2 significant ways • 1. Myelination • 2. Increase in neural pathways
- 50. Changes in Brain Regions • Neurons 2 significant changes • 1st years of life. • 1. Myelination • Covering of axons • Speeds up & insulates transmission • Continues into adolescence. • 2. Increase in neural pathways • Twice as many made than will ever be used.
- 51. How Do Infants Grow and Develop Physically? The Development of Dendrite Spreading At birth 1 month 3 months 15 months 24 months
- 52. Changes in Brain Regions • Heredity & environment • Influence synaptic overproduction & subsequent retraction • Hereditary: • Genes • Environment • Stimulating environment vs. boring • Retraction: Use it or lose it.
- 53. Changes in Brain Regions • Blooming (development or increase) in neurons • Greatest density of brain cells synapses by age 3.
- 54. Changes in Brain Regions • Pruning (decrease) in neurons • Unused connections replaced by or disappear • Vary by brain region • Begins @ early adolescence & ends @ age 16.
- 55. Changes in Brain Regions • Prefrontal cortex • • • Higher-level thinking Self-regulation Not fully developed until @ 23 yrs.
- 56. SLEEP
- 57. Sleep Across the Human Life Span 24 16 Total daily sleep (hours) 14 12 10 8 6 4 2 0 1-15 days Newborn 6 mo 12 mo 18 mo Infants 2 yrs 10 yrs 20 yrs Children Adolescents 30 yrs Adults 40 yrs 50 yrs 60 yrs 70 yrs Older adults 80 yrs 90 yrs
- 58. Sleep • Individual variation in infants sleep • Typical newborn • 16 - 17 hrs day • Times & patterns vary • • • More time in REM By 3 mo’s, % of x in REM sleep decreases By 4 mo. close to adult patterns • Awake day • Sleep night
- 59. Dynamic Systems Theory • Dynamic Systems Theory • • Motor development When motivated, might create a new motor behavior • Ex: Walking • Need to have maturation of nervous system • Motivation to move • Grab a bottle • Practice makes walking smoother & more effective
- 60. Dynamic Systems Theory Mastering a New Skill • Example Walking: • • • Motivated by new challenge Partially accomplishes task “Fine tunes” movements • Smoother • More effective
- 61. Dynamic Systems Theory Mastering a New Skill • “Tuning” • Achieved through repeated cycles • Action • Perception of consequences of action • Practice • Ex: Walking • Child gets bottle when reaches mom.
- 63. Gross Motor Skills • Skills that involve large-muscle activities • Sitting upright without support • 6 - 7 mo’s • Crawling • 8 ½ mo’s • Standing with support • 8 months • Walking • 12 months
- 64. Gross Motor Development 2nd Year • Toddlers become more mobile • 13 – 18 months • Can pull toy attached to a string • Use hands & legs to climb up a number of steps • 18 – 24 months • • • • • Can walk quickly or run stiffly Walk backwards without losing balance Stand & kick a ball without falling Stand & throw a ball Jump in place
- 65. Fine Motor Skills • Fine motor skills • Anything that requires finger dexterity • Picking up a spoon • At birth, very little • 1st 2 yrs refine reaching & grasping • When grabbing something • No longer need to watch their hand • Experience plays a role in reaching & grasping
- 66. Sensation & Perception • Sensation occurs when information interacts with sensory receptors • • • • • Eyes Ears Tongue Nostrils Skin • Perception • Interpretation of what is sensed • Color = blue
- 67. Ecological View • Perception • Functions to bring us in contact with environment & increase adaptation. • Designed for action • When to: • • • duck run reach
- 69. Visual Preference Method • Robert Frantz 1963 • • • Frantz’s Looking Chamber Allowed experimenter to look at infants eyes Infants look at things for different lengths of time. • Infants 2 days old • Prefer patterns
- 71. Perception of Pattern and Depth • Infants prefer look at: • Normal human face opposed to scrambled features • Pretty face • Bulls-eye target or black & white stripes • Rather than a plain circle • Depth perception • Visual cliff • Infants develop ability to use binocular (two-eyed) cues to depth by @ 3 - 4 mo’s
- 72. Visual Acuity in Infants
- 73. Visual Acuity and Color Vision • By 1 yr vision • Approximates that of adult • Color-sensitive receptors (cones) function by 2 months of age
- 74. Hearing, Touch, and Pain • Prenatally at 7 mo. can hear sounds • Mother’s voice • Music • Immediately after birth • Cannot hear soft sounds or pitch as well as adults • Newborns respond to touch & feel pain • Infants display amazing resiliency • Several min. after circumcision (performed without anesthesia) • Can nurse & interact in a normal manner with mothers
- 75. Smell and Taste • Newborns can differentiate odors • Sensitivity to taste • Might be present before birth • 2 hrs of age • Different facial expressions when tasted solutions • • • Sweet Sour Bitter • @ 4 mo. prefer salty tastes • Newborns found to be aversive
- 76. Cognitive Development • Sensorimotor stage • Birth to age 2 • Infants learn to coordinate their senses and their motor behavior. • Organize world into: • • • What can I put in my mouth What is graspable What makes noise
- 77. Sensorimotor Stage • Object permanence • Perception that objects continue to exist even when out of sight.
- 78. Sensorimotor Stage • Self-recognition • • • • Towards end of stage Rouge test Lewis & Brooks 1979 Placed in front of mirror Touched nose at 18 – 24 months.
- 79. Language Development • All languages, common characteristics • Rules • Describe way language works • Infinite Generativity • Can produce endless number of sentences using a limited set of words & rules
- 80. How Language Develops • Babies communicate by sounds & gestures • Sequence of 1st year communication • • • • 1. 2. 3. 4. Crying Cooing Babbling Gestures
- 81. How Language Develops • 1. Crying: • Different types • Can signal distress • 2. Cooing: • 1 - 2 mo., gurgling sounds • Usually express pleasure • With interaction of caregiver
- 82. How Language Develops • 3. Babbling • Middle of 1st yr • Strings of consonant-vowel combinations, such as “ba, ba, ba, ba” • 4. Gestures • 8 - 12 months • Showing & pointing • Showing empty cup • Means fill it
- 83. How Language Develops • First Words • Receptive vocabulary • 5 mo.'s may recognize their name • 13 mo.’s understand 50 words • Spoken vocabulary • 13 mo.’s • Important objects & persons • Dada • Ball • Doggie
- 84. How Language Develops • Spoken vocabulary spurt • 18 mo. old • 50 words • 2 yr. old • 200 words
- 85. How Language Develops • Overextension • Dada may mean all men • Underextension • Use a word too narrowly • Boy may mean only boys his age • Telegraphic speech
- 86. Noam Chomsky • Chomsky's LAD hypothesis • LAD • Language Acquisition Device • Humans prewired to learn language at certain time • Able to detect various features & rules of language • Behaviorists opposed • Reinforced for saying Mama
- 87. Michael Tomasello • Behaviorist • Interaction view of language • Children learn language in specific contexts • Father & baby looking at book • father points to bird • son repeats word • Worldwide children acquire language same time.
- 88. Social Interaction Study, 2 groups of moms & their 18-month-olds Group 1 • Told to smile & touch infants immediately after babies cooed & babbled Group 2 • Told to smile & touch infants in random manner, unconnected to infants sounds
- 89. Social Interaction Study • Results • 1st group • Afterwards made more complex, speech like sounds, such as "da" & "gu." • Underscores?
- 90. Class Exercise • Baby Photos