Development
Conception Prenatal to Birth Influences on Prenatal Development Birth The Newborn
Theories of Child Development
In the beginning...
Aristotle (4th century B.C.) How does life begin? His answer: Epigenesis epigenesis Ex. fertilized chicken eggs
Modern day thoughts...
Let's study physical and behavior development in the womb embryology
Gametes
Conception
egg and sperm contain half of the chromosomes present in all other cells almost all the eggs a female will have are formed during her own prenatal development men produce vast numbers of new sperm continuously
Did you know...
Conception
the egg is the largest cell in the human body every ejaculation carries as many as 500 million sperm and only about 200 ever get near the egg sperm must travel for at least 6 hrs, approximately 6-7 inches to reach the fallopian tubes where conception takes place
Conception- Is it a boy or is it a girl?
Round 1: The Amazing Race...
the sperm determines the sex sperm possessing a Y chromosome (genetic makeup for a boy) are lighter and swim faster about 120-150 males : 100 females
Round 2: Survivor...
about 106 males : 100 females - what happened?
miscarriages are higher with males birth is more challenging - 50% result in Cesarean delivery tend to suffer disproportionately from developmental disorders
Round 3: Audience Participation... boys are more highly valued over females in some cultures (ex.
Inuit tribes in Alaska) government constraints on family size (ex. China) selective abortions due to early prenatal sex determination
Conception- Is it a boy or is it a girl?
Round 1: The Amazing Race...
the sperm determines the sex sperm possessing a Y chromosome (genetic makeup for a boy) are lighter and swim faster about 120-150 males : 100 females
Round 2: Survivor...
about 106 males : 100 females - what happened?
miscarriages are higher with males birth is more challenging - 50% result in Cesarean delivery tend to suffer disproportionately from developmental disorders
Round 3: Audience Participation... boys are more highly valued over females in some cultures (ex.
Inuit tribes in Alaska) government constraints on family size (ex. China) selective abortions due to early prenatal sex determination
Conception- Is it a boy or is it a girl?
Round 1: The Amazing Race...
the sperm determines the sex sperm possessing a Y chromosome (genetic makeup for a boy) are lighter and swim faster about 120-150 males : 100 females
Round 2: Survivor...
about 106 males : 100 females - what happened?
miscarriages are higher with males birth is more challenging - 50% result in Cesarean delivery tend to suffer disproportionately from developmental disorders
Round 3: Audience Participation... boys are more highly valued over females in some cultures (ex.
Inuit tribes in Alaska) government constraints on family size (ex. China) selective abortions due to early prenatal sex determination
Prenatal Development
Conception to 2 weeks
Zygote - Begins with conception and lasts until zygote becomes implanted in the uterine wall. Rapid cell division takes place.
Prenatal Development
3rd to 8th week
Embryo - Following implantation, major development occurs in all the organs and systems of the body. Development takes place through the processes of cell division, cell migration, cell differentiation, and cell death, as well as hormonal influences.
Prenatal Development
Zygote Embryo Fetus Cell Division - Begins 12 hours after fertilization and continues
throughout fetal development.
Cell Migration - Cells move from point of origin to elsewhere in
the embryo.
Cell Differentiation - Cells begin to specialize, fulfilling the
needs of separate bodily structures and functions. Ex. Frog (Wolpert, 1991)
Cell Death (apoptosis) - The selective death of certain cells
as they are no longer needed. Ex. hand
Prenatal Development
3rd to 8th week At 4 weeks, the four folds in the front of the head will become facial features. A heart is visible and is beating and circulating blood. At 5-6 weeks, rapid brain development is occurring. The beginning of an eye is seen, and movement spontaneous is occurring.
Prenatal Development
3rd to 8th week At 8 weeks, the umbilical cord connects the fetus to the placenta. All the internal organs are present and sexual differentiation has started. At 8 weeks gestation, this fetus is able to kick and straighten his legs, turn them round and move his arms up and down.
Prenatal Development
9th week to birth
Fetus - Continued development of physical structures and rapid growth of the body. Increasing levels of behavior, sensory experience, and learning. Fetal breathing
Prenatal Development
9th week to birth At 11-12 weeks, external genitalia have developed and the legs, arms, and fingers can be seen. The chest makes breathing movements. Some reflexes, such as grasping, swallowing, and sucking are present.
Prenatal Development
9th week to birth At 16 weeks, growth of the lower extremities accelerates. The fetus will begin kicking. At 20 weeks, the fetus begins rapidly putting on weight. As it fills the space in the amniotic sac, movements begin to diminish.
Prenatal Development
9th week to birth At 28 weeks, the brain and lungs are sufficiently developed. The eyes can open and they move during REM sleep. The auditory system is functioning, and the fetus hears and reacts to a variety of sounds.
Prenatal Development
Zygote Embryo Fetus
Prenatal Behavior
1. Fetal Behavior
A fetus can swallow, move its arms and legs, yawn, and suck, as early as 11 weeks. A fetus gets ready to breathe outside the womb by "fetal breathing," moving its chest wall in and out, taking in and expelling small amounts of amniotic fluid.
2. Fetal Experiences
Touch Taste (Ex. Sweet flavor, DeSnoo, 1930's) Smell Hearing Sight -
Prenatal Behavior
3. Fetal Learning Learning and memory begin to occur during the fetal period (from 32 weeks) Research indicates that fetuses can recognize familiar smells and sounds Lecanuet et al. (1995) - speech sounds Fetuses heard speech sounds-- "babi." initial presentation increased heart rate decreased heart rate with habituation new sound increased heart rate again DeCasper & Spence (1986) read Dr. Seuss book during last 6 weeks listen to same patterns of speech infants sucked more to familiar than unfamiliar story
Influences on Prenatal Development
1. Maternal Influence
Age Nutrition -
Disease -
Stress -
Influences on Prenatal Development
1. Maternal Influence
Age - too young vs. too old? Nutrition - specific nutrients or vitamins Disease - physical vs. mental Stress - links to hyperactivity in children
2. Environmental Influences (Teratogens)
Drugs
Cigarettes Alcohol
Environmental pollutants
Influences on Prenatal Development
Teratogens - Cigarettes (Moore & Persaud, 1993)
Maternal smoking causes low birth weight and possible cognitive impairments. Secondhand smoking is also harmful.
Influences on Prenatal Development
Teratogens - Alcohol
Drinking can cause fetal alcohol syndrome (FAS), which leads to mental retardation, hyperactivity attention problems, and various organ defects.
Influences on Prenatal Development
Teratogens - Alcohol
Drinking can cause fetal alcohol syndrome (FAS), which leads to mental retardation, hyperactivity attention problems, and various organ defects. Increases in daily consumption produced decreases in IQ scores.
Influences on Prenatal Development
Teratogens - Environmental Pollutants
Newland & Rasmussen (2003) - mercury in Minamata Bay in Japan Unknowingly injected leading to children born with Cerebral Palsy, mental retardation, and other neurological disorders
Influences on Prenatal Development
Impact of Teratogens
Influences on Prenatal Development
Impact of Teratogens
1. depends on the genotype of the organism 2. changes over the course of prenatal development effects are worse when organs and systems are developing (esp. embryonic period) 1. affects a specific aspect of development 2. depends on the dosage 3. damage is not always evident at birth but may appear later in life sleeper effects that show up later in life sometimes make identification of teratogens difficult