Human Development

Question 1

The developing embryo becomes a solid ball of 16+ cells called…

Answer 1

a morula (day 4)

Question 2

The ball of cells hollows out to form a ______ on day 5.

Answer 2

blastocyst

Question 3

Late blastocyst (day 10)

Answer 3

pre-embryo with the embryonic disk, two layers of cells that become the embryo proper

Question 4

Gastrula (day 16)

Answer 4

Embryo with three primary germ layers

Question 5

What are the three primary germ layers?

Answer 5

ectoderm(outer), mesoderm(middle), endoderm(inner)

Question 6

Endoderm forms…

Answer 6

Digestive tract, lungs, liver, and pancreas

Question 7

Mesoderm forms…

Answer 7

muscle, connective tissue(bone), internal reproductive organs, and kidneys

Question 8

Ectoderm forms…

Answer 8

Nervous system and skin

Question 9

Supportive structures

Answer 9

structures that support and protect the embryo

Question 10

Umbilical cord

Answer 10

has stem cells

Question 11

Amniotic sac

Answer 11

• fluid maintains constant temperature and pressure
• contains fetal urine and cells

Question 12

Placenta (fully formed at 10 weeks)

Answer 12

• secretes hormones that maintain pregnancy
• sends nutrients to fetus

Question 13

Multiple Births

Answer 13

Dizygotic twins (fraternal)
Monozygotic twins (identical)

Question 14

When does oogenesis start?

Answer 14

when the neural tube develops

Question 15

Spina bifida

Answer 15

Neural tube defect

Question 16

By 4 weeks…

Answer 16

Heart, CNS, arms and legs start to extend, immature lungs and kidneys start to develop

Question 17

By 7 weeks…

Answer 17

Large head, eyes opened by no lids, cartilage skeleton forms

Question 18

By week 8…

Answer 18

Prenatal human has tiny versions of all structures that will be present at birth

Question 19

A prenatal human is considered a _____ for the first 8 weeks.

Answer 19

embryo

Question 20

Why are the first 8 weeks so important?

Answer 20

Critical period

Question 21

What is the critical period?

Answer 21

The time during pregnancy when teratogens have the most effect on a prenatal human.

Question 22

What is a prenatal human considered from 9 weeks till birth?

Answer 22

fetus

Question 23

During fetal period…

Answer 23

body proportions approach those of a newborn, bone replaces soffter cartilage, nerve and muscle functions become coordinated

Question 24

By 12 weeks…

Answer 24

sucks thumb, kicks, makes fists and faces, and has the beginnings of teeth

Question 25

18 weeks…

Answer 25

vocal cords formed

Question 26

Final trimester…

Answer 26

fetal brain cells link into networks as organs elaborate and grow, and fat fills out the skin

Question 27

Last…

Answer 27

digestive and respiratory system matures

Question 28

Teratogens

Answer 28

chemical or other agents that cause birth defects

Question 29

3 categories of teratogens

Answer 29

1. Vitamins
2. Viruses
3. Drugs

Question 30

Drug teratogens

Answer 30

Thalidomide- limb defects
Alcohol- fetal alcohol syndrome (FAS)
Accutane- birth defects, miscarriage
Cocain- stroke, nervous system

Question 31

Vitamin teratogens

Answer 31

Folic acid deficiency- neural tube defects
Vitamin C excess- immune effects

Question 32

Virus teratogens

Answer 32

Rubella, herpes, HIV, hepatitis B

Question 33

Thalidomide

Answer 33

Many mothers took during early stages of pregnancy to help with morning sickness

Question 34

FAS

Answer 34

Learning and mental disabilities, behavior problems, lack social and communication skills, growth slowed before and after birth