1. Prenatal, Birth, and Postnatal Periods
Chapter 4
Prenatal, Birth, and Postnatal Periods

2. The Back Story moment of conception fixes your genetic make-up
BUT, from that moment, a single cell begins to adapt to its environment. Within 9 mos. increases in size two hundred billion times!

3. A Remarkable Story Transaction between special organism
Zygote - a single-cell fertilized ovum
Unique genetic code
Specialized Environment
Species Typical
Fertilization in fallopian tube (oviduct)
Implantation in uterus
At birth- billions of specialized cells capable of surviving in complex environment

4. Three Prenatal Periods
Ovum-Germinal Period
~ days (travel)
Embryonic Period
~2 -8 weeks (implantation)
Fetal Period
8 -38 weeks (major development)

5. Ovum-Germinal Period Starts as Zygote in fallopian tube
Mitosis produces duplication of cells
32 cell ball called morula
Blastula (Blastocyst) differentiates into:
Embryoblast (Inner cell mass) – develops into the embryo
Trophoblast (Outer protective layer)
Becomes amnion, chorio, placenta, allantois (umbilical cord)
Ends at implantation in the uterus wall

6. Reproduction of Cells during Period of the Ovum
Duplication of undifferentiated cells
As cellular reproduction continues, differentiation begins
By the time it enters uterus, two distinct masses have formed
See notes on Slide #4

7. The Blastula Embryoblast Trophoblast
Inner cell mass
becomes the embryo
Trophoblast
Outer layer of cells
becomes
fetal membranes
amnion
chorion
allantois
Blastula (or blastocyst)- the embryoblast & trophoblast
See notes on slide #4

8. Implantation
Hormones prepare uterine environment Blastula sends out tendrils
Marks end of Germinal Period
Marks the beginning of Embryonic Period

9. Three Embryonic Layers
Endoderm
Innermost
Becomes digestive, respiratory, internal organs (pancreas & liver)
Mesoderm
Center Layer
Muscles, bones, circ. system
Ectoderm
Outermost
Hair, Skin, CNS

10. Period of the Fetus Starts when all basic structures are complete
Period of refinement for survival in outside world

11. Laws of Developmental Direction
Cephalo-caudal
Head - tail (foot)
Proximo-distal
Near-far
Gross - fine
basic - refined

12. Teratogens
Substances or agents present prenatally that cause physical or psychological abnormalities
Laws of developmental direction mean that timing is important
Generally speaking, those having effects during embryonic development will have greater harmful outcomes

13. Teratogen Categories Maternal Diseases Drugs Environmental Hazards
Maternal Characteristics

14. Maternal Diseases Toxoplasmosis
potentially serious disease caused by parasite in undercooked meat and cat feces
Passed to fetus through the placenta
Possible Fetal Complications:
Visual defects & Blindness
Hearing Loss
Mental Retardation
Seizures
Cerebral Defects
Low Birth Weight

15. Maternal Diseases Cytomegalovirus (CMV) Caused by type of herpes virus
Passed to fetus as it passes through birth canal of infected mother or through the breast feeding
Possible fetal complications (which may appear for the next few years):
Mental Retardation
Hearing Loss
Microcephaly

16. Maternal Diseases Rubella Caused by a flu-like virus
so damaging to the fetus during the first 16 weeks of pregnancy that universal immunization is crucial
Passed to the fetus through the placenta
Possible fetal complications: (during first 16 weeks after conception):
Visual Defects / Blindness
Hearing Loss / Deafness
Cardiovascular Defects
Neurological Defects (including AUTISTIC SYMPTOMS!)
growth retardation

17. Maternal Diseases Genital Herpes
viral infection caused by the herpes simplex virus
remains in nerve cells causing periodic recurrences
Passed to the fetus in 3 ways:
1) through the uterus
2) passing through the birth canal
3) immediately after birth
Possible fetal complications:
Visual Defects / Blindness
Cerebral Defects

18. Drugs Cigarette Smoking Increases chances of:
ectopic pregnancy or miscarriage
Low birth weight babies (< 5.5 lbs) results from pre- term delivery and/or poor intrauterine growth
Increased risk of chronic disabilities (e.g., cerebral palsy, mental retardation, learning problems)

19. Drugs Alcohol Intake Even moderate amounts place fetus at risk of:
Lower IQ
Attention Deficits
Learning Deficits
Reduced Social Competence
First Trimester exposure: skull and facial abnormalities
Later in pregnancy: postnatal growth affected

20. Environmental Hazards
Radiation
fetal brain most vulnerable to radiation exposure 8th – 15th week of pregnancy
Decrease in IQ scores
Impaired school performance
Susceptibility to seizures
Changes in the occurrence of major features of physical development

21. Maternal Characteristics
Maternal Age
Malnutrition
Effect in Last Trimester
Nutritional demands of late fetus is greatest

22. Postnatal Development

23. Assessing the Neonate Apgar
developed by Dr. Virginia Apgar in It is administered at 1 minute after birth and again at 5 minutes after birth.
A perfect score is see table on page 126
A = Appearance color should be completely pink
P = Pulse heart rate should be adequate (over 100 beats per minute)
G = Grimace - reflex irritability vigorous cries or withdrawal
A = Activity muscle tone should be strong, an active motion
R = Respiration a good, strong cry

24. Assessing the Neonate
Brazelton Neonatal Behavioral Assessment Scale (NBAS-R)
developed by Dr. Berry Brazelton in 1973 and revised in 2000
A detailed look at the child’s physical and behavioral functioning shortly after birth
Used to assess behavioral capabilities of newborns up to 20 days of age
Looks at 28 behaviors and 18 reflexes in these 7 areas:
Habituation Social Interaction Motor State Organization
Reflexes State Regulation Autonomic System

25. The Ability to Respond to the Environment
Sensory Capability - Receptors
vision
hearing
smelling
tasting
feeling
Sensation - firing of receptors by stimulus
Perception - interpretation of sensory input

26. Nativism versus Empiricism
Nativism - innate - nature
Empiricism - experience - nurture
Behavioral Systems Approach –
Perception is due to both

27. Research on Infant Sensory/Perceptual Capabilities
Common to all methods - Change in Behavior correlated with change in Stimulus

28. Methods of Perceptual Research
Visual Preference (Fantz)
Visual Cliff (E. Gibson & Walk)
Habituation-Dishabituation
Operant Conditioning Procedures

29. Visual Preference Looking Chamber Reflection of stimulus on cornea
The “Basic Problem”
Change in behavior - time gazing
Change in stimulus - different visual stimuli
Limitations –
There may be perception even though there is no preference

30. Looking Chamber - Fantz

31. Visual Cliff Depth Perception “Deep” vs. “Shallow” end
Mother entices the child to crawl
Limitations
Child or kid must be ambulatory
Overcome by monitoring heart rate of babies suspended over each end (Campos)

32. Visual Cliff - E. Gibson

33. Habituation-Dishabituation
Babies can’t suck & listen (watch) at same time.
Establish sucking response
Disrupt it with repeated stimulus (e.g., “Pa”)
With repetition of Pa, child habituates
sucking returns
A new stimulus (e.g., “Ba”) is introduced
If child perceives difference between Ba & Pa, sucking stops - Dishabituation

34. Operant Procedures Behaviors which are reinforced become more frequent
Researcher reinforces response to one stimulus and not to another
If child perceives difference between stimuli than will respond more to reinforced stimulus

35. Operant Conditioning Procedures
Perception
Responses: e.g., head turning, sucking, kicking
Reinforcers: e.g., mother’s voice, milk, visual stimuli, heartbeat.
Memory & Cognition
Kicking mobile in presence of an X produces conjugate reinforcement
In later testing immediate kicking when X is present shows recall of contingency (remembering)

36. Operant Conditioning Procedures
Early Perception
Dr. Seuss passages read by mothers in last trimester.
Infants suck to produce mother-read passages.
Early Socialization
Infant social referencing.

37. Perceptual Abilities as Universal Behaviors
Some abilities are hard wired
Examples
Detect light from dark
Detect horizontal from vertical
Detect sound (phoneme) boundaries

38. Reflexes as Universal Behaviors
Hard - Wired
Present at birth
Do not need much experience
Unlearned thus “Unconditioned”
Reflex is not a behavior but stimulus- behavior relationship

39. Examples of Reflexes
Consummatory
Defensive
Social

40. How Do Reflexes Change? 1. Reflexes May Stay the Same
2. Reflexes May Disappear
3. Reflexes May Be Elicited by New Stimuli - Respondent Conditioning
4. Reflexes May be Elaborated into New Behaviors - Operant Conditioning

41. End of Chapter 4
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