Phys Embryo & Fetal Dev

Question 1

production of birth defects

Answer 1

teratogenesis

Question 2

non-reversible morphological defects present at birth (internal, external, and microscopically)

Answer 2

malformations

Question 3

what is the leading cause of infant mortality?

Answer 3

birth defects

Question 4

which organ system is the major cause of death in infants?

Answer 4

congenital heart defects; can lead to life-long risks

Question 5

which nutrient is especially important to consider during pre-conception status? why?

Answer 5

folate; up to 70% of neural tube defects have been attributed to folate deficiency

Question 6

what is the organogenic period?

Answer 6

Day 17-57

critical growth period in which cells start to organize into different cell types

aka teratogenic period bc embryo is most vulnerable to developing birth defects

Question 7

distinguish between hyperplasia and hypertrophy

Answer 7

hyperplasia = increasing cell #
hypertrophy = increasing cell size

Question 8

day 17 to 8 weeks = what kind of growth?

Answer 8

hyperplasia

Question 9

after 8 weeks = what kind of growth?

Answer 9

hypertrophy

Question 10

sperm + egg = ?

Answer 10

zygote

Question 11

what kind of factors can influence fertilization?

Answer 11

• alcohol (even in males)
• toxins
• medications

Question 12

process in which the fertilized egg divides and the zygote cleaves (increase in cell #)

Answer 12

blastogenesis

Question 13

morula

Answer 13

egg with a mass of cells; forms a cavity to result in a blastocyst

Question 14

blastocyst

Answer 14

has a space w/cells inside called embryoblasts (embryo); outer called trophoblasts (placenta)

penetrates endometrium and releases proteolytic enzymes and enable implantation

Question 15

time span of pre-implantation period

Answer 15

<1 week

Question 16

what happens during the pre-implantation period

Answer 16

• increase in cell number but no increase in cell size

- potential exposure to toxicants: no effect, slight decrease in growth, or lethality

Question 17

time span of gastrulation phase

Answer 17

2-3 weeks

Question 18

what happens during the gastrulation phase?

Answer 18

• cell migration through primitive streak
• formation of 3 germ layers (ecto, meso and endoderm)
• very susceptible to teratogens

Question 19

which derm comprises brain, CNS, and skin?

Answer 19

ectoderm

Question 20

which derm comprises voluntary muscles, CV and excretory systems?

Answer 20

mesoderm

Question 21

which derm comprises the digestive and respiratory systems and glandular organs?

Answer 21

endoderm

Question 22

when is the general shape of the embryo beginning to manifest?

Answer 22

days 27-29 post-ovulation

Question 23

time span of organogenesis

Answer 23

3-8 weeks

Question 24

what happens during the organogenesis phase?

Answer 24

• organs and body structures established
• cell proliferation, cell migration, cell-cell interactions and tissue re-modeling
• extremely susceptible to teratogenesis
• periods of maximum susceptibility for each forming structure

Question 25

time span of fetal/neonatal phase?

Answer 25

8 weeks to birth

Question 26

what happens during the fetal/neonatal phase?

Answer 26

• tissue differentiation, growth and physical maturation
• toxic exposure –> effects on growth and functional maturation
• CNS and reproductive abnormalities, behavioral and motor deficits

Question 27

what happens during the 8th week of gestation?

Answer 27

accelerated development of placenta