Chapter 2: From Conception to Birth

Question 1

Zygote

Answer 1

The single cell formed from the union of two gametes, a sperm and an ovum.

Question 2

Gamete

Answer 2

A reproductive cell. In humans it is a sperm or an ovum.

Question 3

Genome

Answer 3

The full set of genes that are the instructions to make an individual member of a certain species.

Question 4

Allele

Answer 4

A variation that makes a gene different in some way from other genes for the same characteristics. Many genes never vary; others have several possible alleles.

Question 5

Epigenetics

Answer 5

The study of how environmental factors affect genes and genetic expression — enhancing, halting, shaping, or altering the expression of genes.

Question 6

Genotype

Answer 6

An organism’s entire genetic inheritance, or genetic potential.

Question 7

Phenotype

Answer 7

The observable characteristics of a person, including appearance, personality, intelligence, and all other traits.

Question 8

Methylation

Answer 8

• From birth to death
• egulating gametogenesis, embryonic and placental growth, as well as imprinting and epigenesis

Question 9

Methyl

Answer 9

surrounding each gene enhances, transcribes, connects, empowers, silences, and alters genetic instructions

Question 10

Microbiome

Answer 10

All the microbes (bacteria, viruses, and so on) with all their genes in a community; here the millions of microbes of the human body.

-most microbes are helpful, enhancing life, not harming it.

Question 11

Monozygotic (MZ) twins

Answer 11

Twins who originate from one zygote that splits apart very early in development. (Also called identical twins.) Other monozygotic multiple births (such as triplets and quadruplets) can occur as well.

Question 12

Dizygotic (DZ) twins

Answer 12

Twins who are formed when two separate ova are fertilized by two separate sperm at roughly the same time. (Also called fraternal twins.)

Question 13

Vulnerability During Prenatal Development

The Germinal Period

Answer 13

An estimated 65 percent of all zygotes do not grow or implant properly and thus do not survive the germinal period.

Question 14

Vulnerability During Prenatal Development

The Embryonic Period

Answer 14

About 20 percent of all embryos are aborted spontaneously. This is usually called an early miscarriage, a term that implies something wrong with the woman when in fact the most common reason for a spontaneous abortion is a chromosomal abnormality.

Question 15

Vulnerability During Prenatal Development

The Fetal Period

Answer 15

About 5 percent of all fetuses are aborted spontaneously before viability at 22 weeks or are stillborn, defined as born dead after 22 weeks. This is much more common in poor nations

Question 16

Vulnerability During Prenatal Development

Birth

Answer 16

Because of all these factors, only about 27 percent of all zygotes grow and survive to become living newborn babies.

Question 17

Germinal: First 14 Days

Answer 17

• Conseption
• occurs when a sperm and an ovum join to form a zygote, the only time when two cells become one. This usually occurs in one of the woman’s fallopian tubes, which connects the ovary to the uterus, but it can also occur in a laboratory dish, through in vitro fertilization (IVF)

Question 18

Embryo: Third week through Eighth week

Answer 18

After second week
- thin line called the primitive streak appears down the middle of the cell mass; it forms the neural tube 22 days after conception
- develops into the central nervous system, that is, the brain and spinal column
- head appears, as eyes, ears, nose, and mouth start to form and a minuscule blood vessel that will become the heart begins to pulsate

After fifth week
- buds that will become arms and legs emerge. Upper arms and then forearms, palms, and webbed fingers grow. Legs, knees, feet, and webbed toes, in that order, appear a few days later, each with the beginning of a skeleton

End of eighth week
-mbryo weighs just one-thirtieth of an ounce (1 gram) and is about 1 inch (½
centimeters) long. It moves frequently, about 150 times per hour, imperceptible to the woman

Question 19

Cephalocaudal

Answer 19

Head-to-Tail

Up until adolsence, then reverse

Question 20

Proximodistal

Answer 20

Near-to-far

Up until adolsence, then reverse

Question 21

Fetus: From ninth week till birth

Answer 21

• encompasses dramatic change, the transformation of a tiny, sexless creature smaller than the final joint of your thumb to a newborn boy or girl about 20 inches (51 centimeters) long
• At end of embryonic period, 23rd pair of chromosomes usually produce hormones that cause the reproductive organs to develop inside (ovaries) or outside (testicles and penis) the body, also develop brain and body

Question 22

3 - 6 months

Answer 22

• active
• heartbeat becomes stronger and faster when the fetus is awake and moving
• Digestion and elimination develop
• Fingernails, toenails, and buds for teeth form, and hair grows, including eyelashes

Question 23

Age of Viability

Answer 23

The age (about 22 weeks after conception) at which a fetus might survive outside the mother’s uterus if specialized medical care is available.

-Birth before 22 weeks = certain death

Question 24

Final Three Months

Answer 24

• benefits the fetal brain and body
• the neurological, respiratory, and cardiovascular systems all develop
• various lobes and areas of the brain are also established, and pathways between one area and another are forged

Question 25

Down Syndrome (characteristics)

Answer 25

a thick tongue, round face, and slanted eyes, as well as distinctive hands, feet, and fingerprints. The hippocampus (important for memory) is usually smaller.

• may have hearing problems, heart abnormalities, muscle weakness, and short stature. They are slow to develop intellectually, especially in language, with a notable deficit in the ability to rhyme

Question 25

Down Syndrome

Answer 25

A condition in which a person has 47 chromosomes instead of the usual 46, with 3 rather than 2 chromosomes at the 21st site. People with Down syndrome typically have distinctive characteristics, including unusual facial features, heart abnormalities, and language difficulties. (Also called trisomy-21.)

Question 26

Fragile X Syndrome

Answer 26

A genetic disorder in which part of the X chromosome seems to be attached to the rest of it by a very thin string of molecules. The cause is a single gene that has more than 200 repetitions of one triplet.

Question 27

Teratogen

Answer 27

drugs, viruses, pollutants, malnutrition, stress, and more — that increases the risk of prenatal abnormalities and birth complications

Question 28

Times during pregnancy most critical for body formation

Answer 28

germinal and embryonic periods, teratogens can affect the fetal brain at any time

Question 29

Fetal Alchol Syndrome (FAS)

Answer 29

A cluster of birth defects, including abnormal facial characteristics, slow physical growth, and reduced intellectual ability, that may occur in the fetus of a woman who drinks alcohol while pregnant.

Question 30

LBW

Answer 30

A body weight at birth of less than 2,500 grams (5.5 pounds)

Question 31

VLBW

Answer 31

A body weight at birth of less than 1,500 grams (3 pounds, 5 ounces).

Question 32

ELBW

Answer 32

A body weight at birth of less than 1,000 grams (2 pounds, 3 ounces).

Question 33

Preterm

Answer 33

A birth that occurs two or more weeks before the full 38 weeks of the typical pregnancy — that is, at 36 or fewer weeks after conception.

Question 34

SGA

Answer 34

A term for a baby whose birthweight is significantly lower than expected, given the time since conception. For example, a 5-pound (2,265-gram) newborn is considered SGA if born on time but not SGA if born two months early. (Also called small-for-dates.)

Question 35

Reasons for LBW

Answer 35

-Malnutrition
Drug use
-Multiple births

Question 36

Consequences of LBW

Answer 36

• Every developmental milestone — smiling, holding a bottle, walking, talking
• ates of cognitive, visual, and hearing impairments increase
• may cry often, pay attention less, and disobey more

Question 37

Immigrant paradox

Answer 37

The surprising, paradoxical fact that low-SES immigrant women tend to have fewer birth complications than native-born peers with higher incomes.

Question 38

Oxytocin

Answer 38

After 38 weeks, starts labor

Question 39

Birth Positions

Answer 39

standing, squatting, or sitting, and give birth upright

Question 40

Doula

Answer 40

A woman who helps with the birth process. In Latin America, traditionally a doula was the only professional who attended childbirth. Now doulas are likely to arrive at the woman’s home during early labor and later work alongside a hospital’s staff.

Question 41

Ceserean Section

Answer 41

A surgical birth in which incisions through the mother’s abdomen and uterus allow the fetus to be removed quickly instead of being delivered through the vagina.

Question 42

APGAR scale

Answer 42

A quick assessment of a newborn’s health, from 0 to 10. Below 5 is an emergency — a neonatal pediatrician is summoned immediately. Most babies are at 7, 8, or 9 — almost never a perfect 10.

color, heart rate, cry, muscle tone, and breathing

Question 43

Kangaroo care

Answer 43

A form of newborn care in which mothers (and sometimes fathers) rest their babies on their naked chests, like kangaroo mothers that carry their immature newborns in a pouch on their abdomen.

Question 44

Postpartum depression

Answer 44

A new mother’s feelings of inadequacy and sadness in the days and weeks after giving birth.

Question 45

Couvade

Answer 45

Symptoms of pregnancy and birth experienced by fathers.