Basics of Prenatal Development

Question 1

What are the three stages of prenatal development?

Answer 1

Fertilization (germinal) stage
Embryonic stage
Fetal stage

Question 2

Time frame for the fertilization/germinal stage

Answer 2

2 wks. after conception

Question 3

Time frame for the embryonic stage

Answer 3

Weeks 3-8

Question 4

Time frame for the fetal stage

Answer 4

Weeks 9 to birth

Question 5

What occurs during the fertilization/germinal stage?

Answer 5

Cellular division and implantation

Question 6

What occurs during the embryonic stage?

Answer 6

Major organ system formation

Question 7

What occurs during the fetal stage?

Answer 7

Final growth and functional maturation

Question 8

Define fertilization

Answer 8

Sperm meets egg (forms zygote)

Question 9

Define cell division

Answer 9

Rapid mitosis

Question 10

What is created after rapid mitosis?

Answer 10

Blastocyst

Question 11

Define implantation

Answer 11

When the blastocyst embeds in uterine wall (by day 10)

Question 12

What are the key events that occur during the fertilization/germinal stage?

Answer 12

Fertilization - Zygote formation
Cell division - Rapid mitosis (forms blastocyst)
Implantation - Blastocyst embeds in uterine wall

Question 13

What are the key events that occur during the embryonic stage?

Answer 13

Gastrulation
Musculoskeletal/Nervous System development
Organogenesis (other major system development)

Question 14

When does gastrulation occur?

Answer 14

Weeks 3-4

Question 15

What does gastrulation consist of?

Answer 15

Development of the ectoderm, mesoderm, and endoderm

Question 16

What is the purpose of ectoderm formation?

Answer 16

Development of nervous system, skin, and other sensory organs

Question 17

What is the purpose of mesoderm formation?

Answer 17

Development of muscle, bone, and the circulatory system

Question 18

What is the purpose of endoderm formation?

Answer 18

Development of digestive tract, lungs, and liver

Question 19

When does the primitive heart tube begin pulsating?

Answer 19

Around day 20

Question 20

When does development of the musculoskeletal and nervous system occur?

Answer 20

Weeks 5-6

Question 21

What are the important components of musculoskeletal formation?

Answer 21

Somites (segment along neural tube)
Limb buds emerge
Cartilage templates form

Question 22

What are the important components of neural development?

Answer 22

Neural tube closes (eventually become the spinal cord and brain; starts differentiating)
Formation of brain vesicles (different regions of the brain)

Question 23

When does organogenesis and major system development occur?

Answer 23

Weeks 6-8

Question 24

What is organogensis?

Answer 24

Stage of development where the body’s organs begin to form (differentiate into major systems of body)

Question 25

What other body systems develop during the embryonic stage (weeks 6-8)?

Answer 25

Cardiovascular system Respiratory system Urinary system Digestive system

Question 26

What forms during cardiovascular system development?

Answer 26

Heart chambers (regular beating begins soon after)

Question 27

What forms during respiratory system development?

Answer 27

Branching of lung buds (further airway development)

Question 28

What forms during urinary system development?

Answer 28

Kidneys Urogenital separation (urinary and genital tracts become distinct features)

Question 29

What forms during digestive system development?

Answer 29

Liver Pancreas Intestines

Question 30

What are the three periods that occur during the fetal stage?

Answer 30

Early fetal period Mid fetal period Late fetal period

Question 31

Time frame for the early fetal period

Answer 31

Weeks 9-12

Question 32

Time frame for the mid fetal period

Answer 32

Weeks 13-24

Question 33

Time frame for the late fetal period

Answer 33

Weeks 25 to birth

Question 34

What occurs during the early fetal period (weeks 9-12)?

Answer 34

First movements appear Limbs begin to elongate Differentiation of external genitalia

Question 35

What occurs during the mid fetal period (weeks 13-24)?

Answer 35

Rapid growth Lanugo covers body of fetus (fine soft hair) Development of muscle tone Mother begins to feel movement

Question 36

What occurs during the late fetal period (weeks 25 to birth)?

Answer 36

Organ system maturation (lungs) Rapid brain growth Sensory development completes

Question 37

What are some examples of congenital conditions?

Answer 37

Neural tube defects Clubfoot Hip dysplasia Torticollis

Question 38

What movement foundations develop during the prenatal period?

Answer 38

Primitive reflexes Muscle tone Joint mobility

Question 39

What is a teratogen?

Answer 39

Any agent that can cause harm to the developing embryo or fetus (drugs, infections, medications)

Question 40

What does fetal viability mean?

Answer 40

The point at which a fetus can survive outside the womb

Question 41

What is the outermost germ layer of the embryo?

Answer 41

Ectoderm

Question 42

What is the middle germ layer of the embryo?

Answer 42

Mesoderm

Question 43

What is the innermost germ layer of the embryo?

Answer 43

Endoderm

Question 44

What do somites give rise to?

Answer 44

Vertebrae Ribs

Question 45

What structure connects the fetus to the placenta and carries oxygen and nutrients to the fetus?

Answer 45

Umbilical cord

Question 46

What structure is a fluid-filled sac that cushions/protects the fetus?

Answer 46

Amniotic sac

Question 47

What is an oocyte?

Answer 47

An immature egg cell