Chapter 2

Question 1

how many chromosomes do people have (those without an abnormality)

Answer 1

46chromosomes

23 from mom and 23 from dad

Question 2

Three stages of Prenatal Development

Answer 2

first 2 weeks - Germinal stage
weeks 3-8- Embryonic stage
weeks 9-birth- Fetal stage

Question 3

germinal stage

Answer 3

zygote forms within 36hours; cells divide every 12-15hrs and make way down fallopian tube; cells differentiate into layers; implantation happens when the 100cell blastocyst embeds into the uterine wall; placenta develops

Question 4

embryonic stage

Answer 4

most fast paced period of development; the circulatory system forms; neural tube develops; by day 26 arm buds develop; legs, rudimentary feet, elbows, wrists, precursors of fingers can be seen; by week 8 all internal organs are in place

Question 5

fetal stage

Answer 5

development occurs at a more leisurely pace; eyebrows, fingernails, etc.
neurons migrate and begin stages themselves in different areas (the brain doubles in size from month 4to 7); at 6mos hearing and at 7mons sight

Question 6

age of viability

Answer 6

22-23 weeks

Question 7

gestational period

Answer 7

38-40weeks

Question 8

principles of development

Answer 8

Proximodistal (interior to exterior ie: heart before arms)
Cephalocaudal (head to feet ie: crawl before walk)
Mass-to-Specific (larger to complex ie: arms before fingernails)

Question 9

Down Syndrome

Answer 9

extra chromosome on 21 pair (therefore have 47)
flat facial profile; upward slant to eyes; stocky; enlarged tongue; risk of having heart defects and childhood leukemia
can cause MR and is higher risk for older mothers

Question 10

Klinefelter syndrome

Answer 10

usually results in a male with an extra X chromosome (XXY); smaller genitalia, enlarged breasts, tall stature and often infertile

Question 11

Turner syndrome

Answer 11

usually occurs dot to missing X chromosome in females (XO)

small stature, webbed neck, heart defects and often infertile

Question 12

Teratogens

Answer 12

substances that may cross the placenta and cause harm to the developing embryo or fetus

1. most likely to cause major structural damage during the embryonic stage
2. can affect the developing brain throughout pregnancy
3. have a threshold above which damage occurs
4. exert their damage unpredictably, depending on fetal and maternal vulnerabilities

Question 13

critical period

Answer 13

when a specific organ or system is coming “on line”

Question 14

Categories of teratogens (there are 5)

Answer 14

Infectious diseases 
medications 
recreational drugs 
environmental toxins 
Vitamin deficiencies

Question 15

Thalidomide

Answer 15

given to pregnant women from 1957-1962 in Europe and Japan and more than 12k children had limb malformations and organ system difficulties

Question 16

Rubella effects on embryos

Answer 16

can cause blindness, deafness, and MR (if mother contracts Rubella later in pregnancy there may be minimal to no side effects)

Question 17

Tobacco effects on embryos

Answer 17

premature birth, low birth weight, cleft palate and higher risk of miscarriage

Question 18

Alcohol effects on embyros

Answer 18

most common cause of MR in the united states; causes Fetal Alcohol Spectrum Disorders
ETOH should NEVER be had during pregnancy

Question 19

Why is gestational diabetes dangerous to a baby

Answer 19

because it can affect neurobehavioral development and cognitive abilities

Question 20

Can men’s sperm be effected? And if so, what should they avoid

Answer 20

Yes
Lead, tobacco, THC, Cocaine, ETOH, radiation, pesticides and low vitamin C have been linked to teratogens within men. And smoking near a pregnant woman has a greater risk of low birthweight, SIDS, and childhood cancer