Chapter 2: Prenatal Development

Sleeper effects

impact of a given agent may not be apparent for many years

Prenatal Development: Sex Differences Graph

- Beginning at birth, the U.S. male-to-female mortality ratio exceeds 1 across the lifespan - The spike that occurs in adolescence and early adulthood--peaking at 3 male deaths for every female death - Males 3x more likely to die than females due to external causes over internal causes

Fetal

- Continued development of physical structures and rapid growth of the body - Increasing levels of behavior, sensory experience and learning

Embryonic

- 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

How can selective cell death → enhanced learning?

- Less is more - Exuberant learning can be detrimental - Our brain sucks up a ton of energy (i.e. starving after studying)

Maternal teratogens

- aids, chicken pox, herpes, chlamydia, influenza, syphilis - toxoplasmosis- a parasite that is mainly active in cats and rats and goes into the rats system after they eat cat poop and attaches to their brain stem and makes them less afraid of cats so cats eat them and the cycle starts again

Roles of hormones

- huge role in sexual differentiation - genitalia development based on the presence or absence of testosterone

Fetal Rest-Activity Cycles

- it mirrors the mother, if mom is asleep fetus tries to sleep - circadian rythms are apparent - near the end of pregnancy, sleep and wake states are similar to the newborn

Cigarette smoking and pregnancy

- linked to retarded growth and low birth weight - chemicals pass placental barrier - SIDS- sudden infant death syndrome

Placenta

- passes oxygen and nutrients from the mother's blood into the embryo or fetus - removes waste materials from the embryo or fetus

Concept of the wru

- when the baby comes into the world its thinking about it but then the umbilical cord falls off and its committed to being alive - if the baby dies before, not a hard emotional attachment to lose - noncommittal view of infancy because infants are relatively easy to die

What are the four major developmental processes transform a zygote into an embryo and then into a fetus?

1. Cell division 2. Cell migration 3. Cell differentiation 4. Apoptosis

At 20 weeks what does doctor look for?

1. Foreshortened neck = abnormalities 2. Scans for sex of baby

The three periods of prenatal development

1. Germinal (conception-2 weeks) 2. Embryonic (3rd - 8th week) 3. Fetal (9th week - birth)

Examples of sensory structures

1. Tactile (touch) 2. Sounds 3. Visual (negligible)

Male embryos are more likely than female to:

1. miscarried at higher rates 2. more likely to face c-section 3. more vulnerable to developmental disorders

What are some examples of how familiarity breeds preference?

1. recognition of rhymes and stories presented before birth 2. preference of smells, tastes, and sound patterns that are familiar because of prenatal exposure

How does the fetus contribute to its own growth?

1. swallowing of amniotic fluid 2. movement of the chest wall and pulling in and expelling small amounts of amniotic fluid

Around ____ of conceptions result in very early miscarriages

1/3 +

Approx ______ males are conceived for every ____ females

120-150; 100

____% of pregnancies of which women are aware are miscarried

15-20%

What percentage of all viable eggs survive?

> 50%

Meiosis

A specialized cell division that results in each gamete having only half the genetic material of all other normal cells in body

Blastocyst

A structure formed in the early development of mammals. It possesses an inner cell mass (ICM) which subsequently forms the embryo.

Why are mother's food choices important?

Allergies - i.e. small dosing of peanut butter in womb can help child's body build resilience to the allergy

Fetal habituation

At about 30 weeks gestation, fetus decreases responses to repeated or continued stimulation

When does crossing over occur?

Before genetic material goes into sex cells (meiosis)

Miscarriage

By far most common misfortune in prenatal development is spontaneous abortion

Trophoblast

Cells that outer layer of the blastocyst consists of collectively

Fetal face Development from 5 ½ - 8 weeks

Cephalocaudal Development

Teratogens

Environmental agents that have potential to cause harm during prenatal development (crosses placental barrier)

Germinal period

Extremely rapid cell division of zygote (begins approx 36 hours after conception)

Dose-response relation

Increases in exposure to potential teratogens = greater possibilities of fetal defects and with more several problems

Endometrium

Lining of uterine wall that bursts if you don't have an egg implanted into it (period)

Cell migration

Movement of cells from point of origin to somewhere else in embryo

Individual differences

Particular genetic makeup, level of motivation/ability to overcome disability that influence the effects of teratogens

The embryonic support system

Placenta Placental barrier Umbilical cord Amniotic sac

Cell division (mitosis)

Proliferation of cells, egg + sperm → human

Conception

Results from the union of two gametes

Apoptosis

Selective death of certain cells, cell-suicide, enables prenatal development

Gametes

Sex cell that is a sperm in males and egg (oocyte) in females produced in meiosis

Defects associate with neural tube

Spitobipita

T or F? Things that come from inside or outside mother that can affect prenatal development?

TRUE

Crossing over

Takes the chromosome that you have and reorders them → a lot of genetic variation even within sperm

Cell differentiation

Transforms embryo's unspecialized stem cells into roughly 350 different types of cells

Sensitive period in development

When a lot of action in the CNS is happening so the fetus is particularly vulnerable to teratogens

Approximately what is the delay between fertilization and implantation?

about one week

Examples of teratogens

alcohol, smoking, body oils, etc.

_______ helps shape our actual physical shape

apoptosis

Why are there many more males conceived than females?

bc sperm bearing the Y chromosome are lighter and swim faster to the egg (more fragile) than those bearing an X chromosomes

Why do women often get illnesses during pregnancy?

because her immune system will often attack the blastocyst

Inner cell mass

bunched up cells that, once fertilized, will eventually give rise to the definitive structures of the fetus

When do sex differences begin?

conception

As the first stimulus is repeated and becomes familiar, the response to it gradually _______

decreases

Fetal Rest-Activity Cycles become stable when?

during second half of pregnancy

Internal cause

illness, disease, genetic abnormalities

One can get sense of baby's personality through their _______ ________

fetal movement

Habituation window

first instances of response to a compelling stimulus

We develop starting where?

from the head down

By 12 weeks after _____, most of the movements that will be present at birth have appeared

gestation

Fetus's movement of chest wall and expulsion of amniotic fluid

helps the respiratory system become functional

External cause

homicide, suicide, accidents due to recklessness

______ play crucial role in sexual differentiation

hormones

Phylogenetic continuity

idea that that because of our common evolutionary history, humans share many characteristics, behaviors, and developmental processes with other animals, especially mammals

Males more vulnerable to _____ throughout life span

illness

Doula

individual trained to assist women in terms of both emotional and physical comfort during labor and pregnancy

If testosterone is present = _____; otherwise default is _____ genitalia

male; female

Fetal alcohol syndrome

maternal alcoholism that is associated with mental retardation, facial deformity and other problems; incurable

Prenatal habituation

measure movement or heart rate (how fetus indicate interest, minor excitement)

What is the kick off of the growth of an embryo?

once the zygote becomes implanted in uterus

Monozygotic

one zygote (egg)

Sensory structures

present relatively early in prenatal development and play a vital role in fetal development and learning

Fetus's swallowing of amniotic fluid

promotes the normal development of the palate and aids in the maturation of the digestion system→ toughens and hardens palette, so when they come out, they're ready to nurse

When a novel (new, unfamiliar) stimulus occurs, the response _______

recovers

Identical twins (monozygotic)

result from a splitting in half of the inner cell mass, have the same genetic makeup

Neural tube

the groove formed in the layer of the differentiated cells int he embryo that eventually become the brain and spinal cord (central nervous system)

_____ dictates whether one is male or female

sperm

Zygote

sperm + egg

_____ can lead to spontaneous abortion or miscarriage

teratogens

All human fetuses can develop either male or female genitalia, depending on the presence or absence of _________

testosterone

After implantation, inner cell mass becomes what?

the embryo

What do the rest of the cells that don't become the embryo develop into?

the embryo's support system

Epigenesis

the emergence of new structures and functions in the course of development

What makes identifying teratogens difficult?

the existence of sleeper effects

Decreased response to the repeated stimulus indicates what?

the formation of memory for it; the increased response to the novel stimulus indicates discrimination of it from the familiar one, as well as a general preference for novelty

Placental barrier

the interface between the amniotic sack and the uterus, acts as a semipermeable membrane between the mother and the baby, letting good shit in and bad shit out

Umbilical cord

the interface between the placenta and the baby, it's how the baby is nourished

Implantation

the process in which the balls of cells (germinal period) starts to become embedded in the wall of the uterus

Gestation

the process of carrying or being carried in the womb between conception and birth

Habituation occurs in response to what?

the repeated presentation of a stimulus

_____ marks the beginning of the three periods of prenatal development

the zygote

Near end of pregnancy, the fetus's sleep and wake states are similar to whose?

those of a newborn

_____ is a crucial factor in the severity of the effects of potentially harmful agents

timing

Dizygotic

two zygotes (eggs)

Amniotic fluid takes the predominance spice or food of particular mother's culture

wTransmits her love of curry → amniotic fluid can smell like curry

Spitobipita

when neural tube doesn't close properly and leakage of spinal fluid, prevented with folic acids

Fraternal twins (dizygotic)

when two eggs happen to be released from the ovary into the fallopian tube and both are fertilized

Amniotic sac

where baby is floating, has a lot less room towards end of pregnancy than beginning, amniotic fluid related to baby's development of taste and smell