Chapter 4 - Prenatal development

Question 1

when is the germinal period or period of the zygote

Answer 1

from conception to implantation in uterine wall

Question 2

when is the period of the embryo

Answer 2

from week 3 to week 8

Question 3

when is the period of the fetus

Answer 3

from week 9 to birth

Question 4

when do support structures develop

Answer 4

once implantation has occurred

Question 5

what are examples of support structures in pregnancy

Answer 5

• amnion
• chorion
• placenta
• umbilical cord

Question 6

what three cell layers form during the period of the embryo

Answer 6

• ectoderm
• mesoderm
• endoderm

Question 7

what is the ectoderm

Answer 7

will become nervous system, skin, hair

Question 8

what is the mesoderm

Answer 8

will become muscles, bones circulatory system

Question 9

what is the endoderm

Answer 9

• will become digestive system, lungs, urinary tract, other vital organs
• portion of endoderm forms neural tube

Question 10

what happens during the second month of pregnancy

Answer 10

• ears are formed
• rudimentary skeleton
• limbs develop
• brain develops rapidly
• indifferent gonad appears
• about 2.5 cm long and 7 g

Question 11

what happens during the third month of pregnancy

Answer 11

• able to kick, twist, but not felt by mother
• can swallow, digest, urinate
• testosterone secreted by testes of males
• ultrasound can detect sex
• 7.5 cm long and under 28 g

Question 12

what happens during months 4 through 6 of pregnancy (second trimester)

Answer 12

• more refined motor action
• kicking may be felt by mother
• heartbeat can be heard with stethoscope
• eyebrows, eyelashes, scalp hair appear
• covered with vernix (white, cheesy covering to prevent chapped skin)
• covered with lanugo (fine layer of body hair)

Question 13

what happens during months 7 through 9 (third trimester)

Answer 13

• the “finishing phase”
• organ systems mature
• weight gain
• moves to head-down position in ninth month
• 48 to 53 cm long and 3.2 to 3.6 kg

Question 14

what is the age of viability

Answer 14

22 to 28 weeks
- survival outside uterus possible

Question 15

what is a teratogen

Answer 15

environmental agents such as viruses, drugs, chemicals, radiation that can harm developing fetus

Question 16

maternal influences on prenatal development

Answer 16

• nutrition
• emotional well-being
• age

Question 17

what is a sensitive period during development

Answer 17

a time when it is particularly susceptible to damage from teratogens

Question 18

what is rubella

Answer 18

a maternal disease
- most dangerous in first trimester
- effects include blindness, deafness, cardiac abnormalities, intellectual disability

Question 19

what is toxoplasmosis

Answer 19

a maternal disease
- caused by a parasite acquired from undercooked meat or handling feces from cats
- effects include brain damage in first trimester; miscarriage thereafter

Question 20

sexually transmitted diseases/infections from mother

Answer 20

• syphilis
• genital herpes
• HIV/AIDS

Question 21

how does syphilis effect baby

Answer 21

• not dangerous until 18th prenatal week
• effects include eye, ear, bone, heart defects, brain damage, miscarriage

Question 22

how does genital herpes effect baby

Answer 22

• most infectious at birth
• effects include death, blindness, brain damage, neurological disorders

Question 23

how does HIV/AIDS effect baby

Answer 23

screening and antiretroviral treatment have reduced prenatal transmission to 2% (in NA and europe)
- effects of exposure to HIV in developing countries include low birth weight, impaired early growth, impaired psychomotor and cognitive development, and immune issues

Question 24

what is thalidomide and its effects

Answer 24

originally marketed to relieve morning sickness
- harmful when taken early in human pregnancy
- many babies born with severely deformed eyes, ears, noses, hearts, and phocomelia (missing or shortened arms/legs)

Question 25

what is diethylstilbestrol (DES) and its effects

Answer 25

originally used to prevent miscarriages
- effects not apparent until early adulthood

Question 26

what is fetal alcohol syndrome caused by and its effects

Answer 26

caused by heavy drinking
- effects include microencephaly, facial malformation, hyperactivity, seizures, below average intelligence

Question 27

what are fetal alcohol effects caused by and its effects

Answer 27

caused by moderate, social drinking
- effects include poor motor skills, attention problems, below average intelligence

Question 28

effects of cigarette smoking on baby during prenatal development

Answer 28

• low birth weight
• risk of cleft lip with or without cleft palate
• increased risk of miscarriage or SIDS

Question 29

effects of cocaine on babies during prenatal development

Answer 29

• premature birth
• lower IQ

Question 30

effects of heroin on babies during prenatal development

Answer 30

• increased neonatal death
• born addicted
• may recover

Question 31

effects of marijuana on babies during prenatal development

Answer 31

• emotional, behavioural and academic problems

Question 32

effects of radiation on babies during prenatal development

Answer 32

high exposure can result in serious physical deformities, intellectual disabilities, death

Question 33

effects of chemicals and pollutants on babies during prenatal development

Answer 33

can cause physical deformities and intellectual disabilities

Question 34

effects of maternal diet on babies during prenatal development

Answer 34

• malnutrition results in small babies
• adequate protein-calorie intake crucial to brain development
• folic acid (folate) is crucial for neural tube development

Question 35

spina bifida

Answer 35

a defect occurring during neural tube development

Question 36

what are the effects of stress on mother during prenatal development

Answer 36

more stress = lower birth weight = more birth complications

Question 37

what percent of newborns are healthy

Answer 37

95%