PSY 213 Lecture Notes - Lecture 2: Amniotic Sac, Umbilical Cord, Prenatal Development
Chapter 2 – Prenatal devel’ & newborn period PSY 213
JAN 10/18
Themes
- Prenatal devel’
- Conception
- Devel’ processes
- Early devel’
- Fetal b’
- Fetal learning
- Hazards to prenatal devel’
- Birth experience
- Newborn infant
Nature + nurture
Active child
Sociocultural context
Individual differences
Continuity/discon’t
Research + children’s welfare
When does life begin?
Complex + influenced by cultural worldviews.
Beliefs:
- Newborn is ancestral reincarnation.
- Wru not fully committed until umbilical stump falls off; goes be/n wrugbe + earth.
- Mother attempts to make baby happy + content; body is elaborately decorated to increase
pos. attention.
Prenatal devel’
Epigensis
- Aristotle (4th c.)
- Proposed emergence of new structures + functioning during devel’.
Preformation
- Suggested mini, preformed humans lodged inside mothers egg or fathers sperm.
- Some claimed microscopic evidence demonstrating the impact of bias in science.
find more resources at oneclass.com
find more resources at oneclass.com
Chapter 2 – Prenatal devel’ & newborn period PSY 213
JAN 10/18
Conception
- All humans originate from union of two gametes (sperm from father; egg from mother).
- Gametes are produced through meiosis + contain 23 chromo; when united 23 pairs result.
- Almost all eggs are formed prenatally; sperm production con’t throughout life.
Female Reproductive System
- Umbilical cord runs from the fetus to the placenta, which is burrowed deeply into the
wall of the uterus. The fetus is floating in amniotic fluid inside the amniotic sac.
Sex Differences
- Males (Y chromo)
- Faster than X
- 120 to 150 males conceived for every 100 females
- More miscarriages, higher c-sections birth rate
- Higher rate of devel’ disorders
- More birth complications overall
- Females (X chromo)
- Ratio at birth: US 106M, 100 F; CA 105M, 100F
- Higher risk for culturally approxed infanticide + pre-implantation
sorting/selection
Process of repro
- Egg launched from ovary into fallopian tube.
- Triggered by sexual intercourse, egg released + as many as 500m sperm enter vagina.
- Approx 200 near egg 6hrs + 15-17cm later
- High failure rate due to genetics or other defects; survival of the fittest.
Periods of Prenatal Devel’
Conception to 2 weeks – Germinal
- Beings w/conception + lasts until the zygote becomes implanted in the uterine wall.
Rapid division takes place.
3rd to 8th week – Embryonic
- Following implantation, major devel’ occurs in all the organs + systems of the body.
Devel’ takes place through the processes of cell division, cell migration, cell
differentiation, + cell death, as well as hormonal differences.
find more resources at oneclass.com
find more resources at oneclass.com
Chapter 2 – Prenatal devel’ & newborn period PSY 213
JAN 10/18
9th week to birth – Fetal
- Con’t devel’ of physical structures + rapid growth of the body. Increasing levels of b’,
sensory experience, + learning.
Four Developmental processes
- Cell division.
- Cell migration.
- Cell differentiation.
- Cell death (apoptosis)
Hormonal Influence
- Important to cell differentiation.
Embryo Hand Plate
- Fingers emerge from the hand plate of this 7-week-old embryo.
- Fingers are formed as a result of the death of the cells between the ridges you can see in
the plate.
- If these cells did not expire (apoptosis), the baby would be born with webbed rather than
independent fingers.
Early Devel’: Germinal to Embryonic Stages
Day 4: inner cell mass arranged into hollow sphere.
End of week 1: implantation in uterine lining.
During week 2: inner cell mass differentiates into three layers.
After implantation: neural tube created: Brain, spinal cord.
Support system
- Amniotic sac
- Placenta
- Allows baby + mom to exchange nutrients.
- Umbilical cord
- Connects the placenta + baby.
Summary of Prenatal Devel’
Earlier devel’ is faster + follows a cephalocaudal devel’ pattern.
Devel’ begins with the brain/head down.
Embryo at 4 weeks
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Wru not fully committed until umbilical stump falls off; goes be/n wrugbe + earth. Mother attempts to make baby happy + content; body is elaborately decorated to increase pos. attention. Proposed emergence of new structures + functioning during devel". Suggested mini, preformed humans lodged inside mothers egg or fathers sperm. Some claimed microscopic evidence demonstrating the impact of bias in science. All humans originate from union of two gametes (sperm from father; egg from mother). Gametes are produced through meiosis + contain 23 chromo; when united 23 pairs result. Almost all eggs are formed prenatally; sperm production con"t throughout life. Umbilical cord runs from the fetus to the placenta, which is burrowed deeply into the wall of the uterus. The fetus is floating in amniotic fluid inside the amniotic sac. 120 to 150 males conceived for every 100 females. Ratio at birth: us 106m, 100 f; ca 105m, 100f. Higher risk for culturally approxed infanticide + pre-implantation sorting/selection.
