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PSCI 101D > Chapter 2 > Flashcards

Chapter 2 Flashcards

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1
Q

Gamete

A

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

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2
Q

Zygote

A

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

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3
Q

Genome

A

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

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4
Q

Allele

A

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.

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5
Q

Epigenetics

A

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

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6
Q

Genotype

A

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

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7
Q

Phenotype

A

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

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8
Q

Micro biome

A

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

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9
Q

Carrier

A

A person whose genotype includes a gene that is not expressed in the phenotype. The carried gene occurs in half of the carrier’s gametes and thus is passed on to half of the carrier’s children. If such a gene is inherited from both parents, the characteristic appears in the phenotype.

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10
Q

Polygenic

A

Many genes

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11
Q

X-linked

A

A gene carried on the X chromosome. If a male inherits an X-linked recessive trait from his mother, he expresses that trait because the Y from his father has no counteracting gene. Females are more likely to be carriers of X-linked traits but are less likely to express them.

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12
Q

Monozygotic twins

A

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.

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13
Q

Dizygotic twins

A

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

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14
Q

How is the sex of a zygote determined?

A

The 23rd pair of chromosomes is crucial. Every zygote has an X from the mother and either an X or Y from the father. If the zygote has a Y, it usually becomes male

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15
Q

What is the influence of methylation on genes?

A

Methylation is the effect of methyl that surrounds each gene, and “enhances, transcribes, connects, empowers, silences, and alters genetic instructions”

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16
Q

What is the influence of the microbiome?

A

The microbes that live within each person affect almost every function of the human body, influencing moods, digestion, diseases, and the immune system

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17
Q

How do monozygotic twins, dizygotic twins, and single-born siblings differ genetically?

A

Monozygotic twins are from one zygote, and hence are genetically identical, where dizygotic twins come from two ovarian that were fertilized by two sperm at about the same time. They share prenatal influences and birth date, but genetically they are no more alike than single-born siblings from the same parents

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18
Q

How could a child inherit a disease neither parent has?

A

Both parents could carry the same recessive gene, or the alleles from each parent could combine in unfortunate ways

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19
Q

What is the difference between additive genes and recessive genes?

A

Additive genes add up their influence on the future person, with each contributing to the phenotype, whereas recessive genes are hidden and don’t affect the phenotype unless the zygote inherited a recessive gene from both parents

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20
Q

How are boys more likely to inherit disorders from their mother rather than their father?

A

Sone inherit a Y from their fathers, and an X from their mothers. If a recessive gene is on the mother’s X, it may have no dominant gene on the Y to counteract it, so it alone affects the trait

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21
Q

Germinal period

A

The first two weeks of prenatal development after conception, characterized by rapid cell division and the beginning of cell differentiation.

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22
Q

Embryonic period

A

The stage of prenatal development from approximately the third week through the eighth week after conception, during which the basic forms of all body structures, including internal organs, develop.

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23
Q

Fetal period

A

The stage of prenatal development from the ninth week after conception until birth, during which the fetus gains about 7 pounds (more than 3,000 grams) and organs become more mature, gradually able to function on their own.

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24
Q

In vitro fertilization

A

when a sperm and an ovum join to form a zygote using a laboratory dish

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25
Embryo
The name for a developing human organism from about the third week through the eighth week after conception.
26
primitive streak
appears down the middle of the cell mass at day 14; it forms the neural tube 22 days after conception
27
cephalocaudal
head forms first and the extremities last
28
Fetus
The name for a developing human organism from the start of the ninth week after conception until birth.
29
Age of viability
The age (about 22 weeks after conception) at which a fetus might survive outside the mother’s uterus if specialized medical care is available.
30
apoptosis
A process that occurs in the final months of pregnancy — cell death
31
fontanels
which are areas on the top of newborn head where the skull bones have not fused yet
32
What must happen before the developing organism is called an embryo?
Not until 8 weeks after conception does the developing reason have all the body parts of the person (except sex organs). At that point it is called an embryo.
33
When is an embryo about 3 inches long?
About 3 months after conception
34
When and how do sex organs develop?
Sex organs appear about eight or nine weeks after conception, when hormones from the XX or XY propel their growth
35
What brain growth occurs during prenatal development?
The brain grows more rapidly in prenatal development that the brain of any other creature, with the cortex growing so much in the final months that the surface of the brain is bumpy, with hills and valleys
36
What must happen before a fetus is viable?
Brain, lung and heart maturation are crucial, with survival possible (but unlikely) at 22 weeks after conception. Extremely low body weight, below 2 pounds of 1,000 grams, is likely for the fetus born before 30 weeks, but organ maturation is a better indicator of viability than weight
37
Why is the age of viability unlikely to fall below 22 weeks?
Mechanical and surgical intervention, and specialized newborn care, are unable to produce the brain maturation necessary for the organs to function
38
What happens to the fetus in the final trimester?
Weight gain and maturation of all the organs, with lungs and heart the most crucial. In addition, in male fetuses the testicles descend, and in all babies, the skin, skull, and muscles mature, protecting the brain and thus reflexes that foster breathing, sucking, and digestion
39
Spontaneous abortion
Miscarriage
40
Down syndrome
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).
41
Turner syndrome
occurs when only one sex chromosome is present
42
Fragile X syndrome
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
43
Teratogen
An agent or condition, including viruses, drugs, and chemicals, that can impair prenatal development and result in birth defects or even death.
44
Fetal alcohol syndrome
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.
45
spina bifida
the tail of the spine is not enclosed properly (enclosure normally occurs at about week 7
46
anencephaly
when part of the brain is missing.
47
Low birthweight
A body weight at birth of less than 2,500 grams
48
Very low birthweight
A body weight at birth of less than 1,500 grams (3 pounds, 5 ounces).
49
Extremely low birthweight
A body weight at birth of less than 1,000 grams (2 pounds, 3 ounces).
50
Preterm
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
51
Small for gestational age
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.)
52
Immigrant paradox
The surprising, paradoxical fact that low-SES immigrant women tend to have fewer birth complications than native-born peers with higher incomes.
53
What chromosomal miscounts might result in a surviving child?
The most common are a third chromosome at the 21St site, or a missing or extra chromosome at the 23rd site
54
What is the cause and consequence of Down Syndrome?
Down Syndrome is caused by three, not two, chromosomes at the 21St site. That extra chromosome causes many atypical characteristics in appearance, organs, and the brain
55
How likely are you to be a carrier of recessive conditions?
Very likely. Everyone carries several recessive genes
56
Why is sickle-cell disease very common in some parts of Africa?
Sickle-cell is recessive, with carriers more likely to survive is they contracted malaria. In malaria prone regions, carriers were likely to survive and have many children. If two carriers mated, half of their children would inherit the advantageous single recessive, and only one in four would die young
57
What is the role of the genetic counselor?
Genetic counselors analyze family history and bio markers (blood , chromosomes, and so on) to predict genetic conditions in a future child. They explain possibilities; they do not tell prospective parents what to do with the facts they learn.
58
What are the main causes of low birthweight?
Among the most common causes are malnutrition, drug abuse, and multiple births
59
Are there important differences in low birthweight from one nation to another?
Yes. In some nations in Africa and Asia, the most common cause of low birth weight is maternal malnutrition, because food is scarce for everyone. In North America, addiction to cigarettes, alcohol, or illegal drugs is more common than maternal malnutrition
60
What hormone signals the start of labor?
Oxytocin
61
Doula
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.
62
Cesarean section
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.
63
Apgar scale
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.
64
Brazelton Neonatal Behavioral Assessment Scale (NBAS)
A test that is often administered to newborns, which measures responsiveness and records 46 behaviors, including 20 reflexes.
65
breathing reflex
begins even before the umbilical cord, with its supply of oxygen, is cut.
66
sucking reflex
causes newborns to suck whatever touches their lips—fingers, toes, blankets, and rattles, as well as nipples of various textures and shapes
67
rooting reflex
babies turn their mouths toward anything brushing against their cheeks—a reflexive search for a nipple—and start to suck
68
Babinski reflex
When a newborn’s feet are stroked, the toes fan upward.
69
Stepping reflex
When newborns are held upright, feet touching a flat surface, they move their legs as if to walk.
70
Swimming reflex
When held horizontally on their stomachs, newborns stretch out their arms and legs.
71
Palmar grasping reflex
When something touches newborns’ palms, they grip it tightly
72
Moro reflex
When someone bangs on the table they are lying on, they fling their arms out and then bring them together on their chests, crying with wide-open eyes.
73
Kangaroo care
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.
74
Couvade
Symptoms of pregnancy and birth experienced by fathers.
75
What is the typical birth process?
Most babies are born vaginally, when contractions gradually push the fetus past the cervix, through the vagina
76
Who was Virginia Apgar and what did she do?
She was an anesthesiologist who invented the Apgar scale, a quick and easy way to measure the health of the newborn
77
What are the immediate and long-term results of a cesarean birth?
The immediate result is a quicker labor, avoiding the necessity of the fetal head squeezing through the vagina. The long-term results are led breast-feeding and greater likelihood of obesity later in life
78
Why do cesarean rates vary internationally?
Nations differ in how often cesareans are recommended, in how many doctors can perform them, and in how many women want them. The range is from about 1 to 58 percent
79
What are the advantages and disadvantages of a hospital birth versus a home birth?
The advantages of home birth include less stress for the pregnant parent, more involvement of other family members, and less medical intervention (fewer drugs, less surgery). The disadvantage is that, in nations with many doctors and advances hospitals, home births risk medical complications that are best addressed within a hospital
80
How are newborns socially interactive?
All the newborn senses are alert to people, and the sucking reflex is usually strong
81
What causes postpartum depression?
Both biological and social causes, including hormonal fluctuations, reactions to anesthesia, other people (father, friends, medical professionals), and life circumstances (poverty, unwanted child)
82
How are fathers affected by birth?
Typically, they are supportive of the pregnant parent and welcoming of their newborn. In couvade, they may share some of the physical sensations of labor and birth
83
Why is kangaroo care beneficial?
The body warmth and close contact reduce stress in parent and babe, facilitating bonding
84
When does the parent-infant bond form?
The bond can begin before birth, or it may for gradually after birth. Often the birth process itself includes hormones that increase the bond

PSCI 101D (17 decks)

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