develop 1 - unit 3

Question 1

What are the three main periods of prenatal development?

Answer 1

Germinal Period, Embryonic Period, Fetal Period

Question 2

What marks the start of the germinal period?

Answer 2

Fertilisation

Question 3

How long does the germinal period last?

Answer 3

First 2 weeks after conception

Question 4

What is a zygote?

Answer 4

The union of a sperm and egg cell

Question 5

What is the blastocyst?

Answer 5

A structure formed from the zygote after about 4-5 days post-fertilisation

Question 6

What are the two main components of the blastocyst?

Answer 6

• Trophoblast (shell) * Embryoblast (nucleus)

Question 7

What does the trophoblast become?

Answer 7

Structures responsible for nutrition and protection of the developing embryo

Question 8

What does the embryoblast develop into?

Answer 8

The embryo

Question 9

When does the germinal period end?

Answer 9

When the blastocyst is implanted in the wall of the uterus

Question 10

What begins after the germinal period?

Answer 10

The embryonic period

Question 11

How long does the embryonic period last?

Answer 11

From the 3rd through the 8th week after conception

Question 12

What are the support structures formed by the trophoblast?

Answer 12

• Amnion * Yolk sac * Allantois * Chorion

Question 13

What does the amnion become?

Answer 13

A fluid-filled sac surrounding the embryo

Question 14

What is the primary function of the placenta?

Answer 14

To facilitate metabolic transactions between mother and embryo

Question 15

What does the umbilical cord do?

Answer 15

Carries oxygen and nutrients to the embryo and removes carbon dioxide and metabolic waste

Question 16

What are the three layers of cells formed from the embryoblast?

Answer 16

• Ectoderm * Mesoderm * Endoderm

Question 17

What does the ectoderm develop into?

Answer 17

The nervous system, skin, and hair

Question 18

What develops from the mesoderm?

Answer 18

Muscles, bones, and the cardiovascular system

Question 19

What does the endoderm become?

Answer 19

The digestive system, lungs, urinary tract, and other internal organs

Question 20

When does the primitive streak form?

Answer 20

In the third week post-fertilisation

Question 21

What develops from the neural tube?

Answer 21

The central nervous system (brain and spinal cord)

Question 22

What is the average weight of the embryo by the end of the embryonic period?

Answer 22

~1 gram

Question 23

What characterizes the fetal period?

Answer 23

Development from the 9th week post-fertilisation until birth

Question 24

What happens to the indifferent gonad in the fetal period?

Answer 24

It differentiates into male or female sex organs

Question 25

What is the role of the SRY gene?

Answer 25

Triggers the indifferent gonad to produce testes in male embryos

Question 26

How much does the brain increase in size during 4 to 6 months?

Answer 26

6 times

Question 27

What is the age of viability for a fetus?

Answer 27

Around the end of the 6th month (~22 to 24 weeks)

Question 28

What happens to babies born before 27 weeks?

Answer 28

They need intensive care to survive

Question 29

What does the fetus respond to in the last 3 months of pregnancy?

Answer 29

Noises, tastes of food, and behavioral patterns

Question 30

What is the sleeper-effect principle?

Answer 30

Some teratogens cause effects that may not be apparent until later in life

Question 31

What are teratogens?

Answer 31

Non-genetic agents that increase the risk of prenatal abnormalities and birth complications

Question 32

What is the sensitive-period principle?

Answer 32

The effects of a teratogen are more severe when they occur during the rapid growth of a specific anatomy

Question 33

What does the Individual Difference Principle state?

Answer 33

Not all embryos and fetuses are affected by a teratogen; susceptibility varies

Question 34

What is the Dosage Principle?

Answer 34

The longer the exposure to or higher the dose of a teratogen, the more likely it will cause harm

Question 35

What can result from a single teratogen?

Answer 35

A variety of defects

Question 36

What are some examples of teratogens?

Answer 36

* Drugs (e.g., alcohol, cocaine) * Infections (e.g., AIDS, rubella) * Environmental hazards (e.g., lead, mercury)

Question 37

What is a potential effect of thalidomide?

Answer 37

Birth defects in some mothers

Question 38

What can contracting rubella during the first trimester lead to?

Answer 38

Severe birth defects such as blindness and cardiac abnormalities

Question 39

What is the effect of syphilis during pregnancy?

Answer 39

Can cause miscarriage or severe damage to the child

Question 40

True or False: Most pregnancies result in normal births.

Answer 40

True

Question 41

What are spirochetes?

Answer 41

Micro-organisms that can cause disease and cannot cross the placental barrier until the 18th week of pregnancy.

Question 42

What can spirochetes cause if transmitted after the 18th week of pregnancy?

Answer 42

Miscarriage or a child with eye, ear, bone, heart, and brain damage.

Question 43

How does genital herpes affect newborns?

Answer 43

Results in mortality of 30% of infected newborns, and can cause blindness and mental retardation.

Question 44

What is advised for pregnant women with active herpes?

Answer 44

To undergo cesarean delivery to avoid increasing the risk of infecting the baby.

Question 45

What was the purpose of thalidomide in the 1960s?

Answer 45

To treat nausea and vomiting experienced in the first 3 months of pregnancy.

Question 46

When was thalidomide found to cause severe birth defects?

Answer 46

When taken during the first 2 months of pregnancy.

Question 47

What birth defect can occur if thalidomide is taken around the 21st day post-fertilization?

Answer 47

Child likely born without ears.

Question 48

What birth defect can occur if thalidomide is taken around the 25-27th day post-fertilization?

Answer 48

Deformed arms or no arms.

Question 49

What is the impact of alcohol consumption during pregnancy?

Answer 49

Disrupts the function of the placenta, affecting oxygen and nutrient supply.

Question 50

What is Fetal Alcohol Syndrome (FAS)?

Answer 50

A condition affecting children of alcoholic mothers, characterized by microcephaly, deformed heart, and below average intelligence.

Question 51

True or False: There is a well-defined sensitive period for the effects of alcohol on development.

Answer 51

False.

Question 52

What substances pass from the mother to the embryo/fetus during cigarette smoking?

Answer 52

Nicotine and carbon monoxide.

Question 53

What are some effects of cigarette smoking during pregnancy?

Answer 53

Cleft lip, abnormal lung function, increased risk of miscarriage, below average birth weight.

Question 54

What is recommended for prenatal nutrition?

Answer 54

Healthy, high-protein, high-calory diet with specific weight gain recommendations.

Question 55

What vitamins and minerals are important during prenatal development?

Answer 55

Magnesium, zinc, and folic acid.

Question 56

What can folic acid prevent when taken during the first 8 weeks of pregnancy?

Answer 56

Down’s syndrome, spina bifida, and anencephaly.

Question 57

What is the safest age range for pregnancy?

Answer 57

Between 16 and 35 years of age.

Question 58

What are the risks associated with pregnancies in women older than 35?

Answer 58

Increased risk of miscarriage and chromosome abnormalities.

Question 59

How does maternal stress affect fetal development?

Answer 59

Increased stress can influence fetal physiological state, potentially leading to developmental abnormalities.

Question 60

What is amniocentesis?

Answer 60

A prenatal screening technique to detect chromosome abnormalities by sampling amniotic fluid.

Question 61

What is chorionic villus sampling (CVS)?

Answer 61

A technique to extract fetal cells from the chorion for testing chromosome abnormalities.

Question 62

What is the primary advantage of CVS over amniocentesis?

Answer 62

CVS can be performed earlier (8-9 weeks) and analyzed within 24 hours.

Question 63

What is the main disadvantage of CVS compared to amniocentesis?

Answer 63

Higher risk of miscarriage (1/50 vs 1/150).

Question 64

What is ultrasound imaging used for in prenatal diagnostics?

Answer 64

Detecting gross abnormalities, multiple pregnancies, and guiding other procedures.

Question 65

What are the three periods of prenatal development?

Answer 65

Germinal period (zygote), embryonic period (embryo), fetal period (fetus).

Question 66

What factors can increase the risk of abnormalities during prenatal development?

Answer 66

Teratogens, diet, stress, and timing of exposure.

Question 67

True or False: Most pregnancies result in healthy babies.

Answer 67

True.