prenatal development

Question 1

down syndrome

Answer 1

caused by the presence of an extra copy of chromo 21 - failure to separate during meiosis
causes physical abnormalities e.g. flattened skull, short limbs & a protruding tongue
causes disabilities in motor & intellectual development

Question 2

klinefelter syndrome

Answer 2

males have an extra X = XXY
causes undeveloped testes, enlarged breasts
impairments in language, academic, attentional & motor abilities
1/700 male births

Question 3

Fragile X syndrome

Answer 3

results from abnormality in X chromo - becomes constricted & often breaks
causes prominent ears, long face, high-arched palate & soft skin
intellectual/learning disabilities & short attention span
more common in males

Question 4

Turner syndrome

Answer 4

either an X is missing or part of one X is deleted in females
causes short, webbed neck, infertile
difficulty in math but verbal ability is good
1/2000 female births

Question 5

Poly X

Answer 5

triple X pattern - XXX
normal in appearance
1/1000 female births

Question 6

poly Y

Answer 6

triple Y pattern (YYY)
1/1000 male births

Question 7

phenylketonuria (PKU)

Answer 7

individual cannot properly metabolize an amino acid
easily detected but if left untreated results in intellectual disability & hyperactivity
results from a recessive gene
1/10,000-20,000 births

Question 8

sickle cell anemia

Answer 8

genetic disorder that affects RBC
occurs most often in people of African descent
recessive gene cause RBC to become ‘sickle’ shaped = cannot carry oxygen properly = body cells don’t receive enough oxygen = anemia & early death
1/500 african american children

Question 9

Huntington’s disease

Answer 9

dominant disease that causes CNS to deteriorate
causes muscle coordination problems & mental deterioration
symptoms only appear after 35 years
1/18,000-25,000 births

Question 10

germinal period / zygote stage

Answer 10

begins at conception & ends when zygote is implanted - first 2 weeks
creation of zygote, cell division & attachment of zygote to wall
blastocyst & trophoblast develop

Question 11

what is a blastocyst

Answer 11

a cluster of dividing cells made by a fertilized egg
the early stage of an embryo

Question 12

what is a trophoblast

Answer 12

the outer layer of cells that later provides nutrition & support for the embryo

Question 13

the embryonic period

Answer 13

begins when implantation is complete - 3-8 weeks
rate of cell differentiation intensifies
organs appear
3 layers of cells form
life support system for embryo develop

Question 14

what are the 3 layers of cells (embryonic period)

Answer 14

endoderm - inner - develops into digestive & respiratory systems

mesoderm - middle - develops into circulatory, excretory & reproductive systems system, bones and muscles

ectoderm - outer - become NS, brain, sensory receptors & skin parts

Question 15

life support systems for embryo

Answer 15

amnion - an envelop that contains amniotic fluid in which embryo floats & provides temp & humidity controlled env

umbilical cord - contains 2 arteries & 1 vein - connects embryo to placenta

placenta - a disk-shaped group of tissues - small blood vessels from the mother & offspring intertwine but don’t join

Question 16

what happens between weeks 3 - 8

Answer 16

week 3: neural tube forms, eyes begin to appear, heart cells differentiate

week 4: urogenital system becomes apparent, arm & leg buds emerge, 4 heart chambers, blood vessels

week 5-8: arms & legs diff further, face & facial structures, intestinal tract

Question 17

the fetal period

Answer 17

from 2 months - birth
3 months: becomes more active, face & limbs are distinguishable & genitals identifiable
4 months: growth spurt in lower body, mom can feel movements
5 months: skin structures, more active
6 months: eyes & eyelids, hair, grasping reflex, irregular breathing
last 2 months: fatty tissues, function of organs

Question 18

what is a teratogen

Answer 18

any agent that can potentially cause a birth defect or neg alter cog & behavioral outcomes

Question 19

factors of teratogens that influence severity & type of influence

Answer 19

dose - greater the dose, greater the effect
genetic susceptibility - type or severity or abnormality is linked to genotype of both mother & child
time of exposure - damage caused depends on the point in development - embryonic period is more vulnerable

Question 20

effects of alcohol

Answer 20

fetal alcohol spectrum disorders (FASD)
- body malformations e.g. defective limbs, face & heart
- learning problems & intellectual disabilities

no specific time window when alc affects baby the most - causes problems at any stage of develop

Question 21

effects of nicotine

Answer 21

preterm births, low birth weights, fetal & neonatal deaths, respiratory problems & SIDS
ADHD

Question 22

effects of meth

Answer 22

high infant mortality, low birth weight
developmental & behavioral problems

Question 23

effects of marijuana

Answer 23

lower intelligence
prenatal exposure to weed linked to use at 14

Question 24

effects of heroin

Answer 24

withdrawal symptoms e.g. tremors, irritability, abnormal crying, etc.
behavioral problems & attention deficits

Question 25

sensitive period for each body part

Answer 25

CNS: 3-38
Heart: 3- 8
Arms: 4-8
Legs: 4-8
Ear: 4 - 16
Eyes: 4-38
Palete: 7-9
Teeth: 7-16
external Genitalia: 7-38

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