Prenatal Development Week 4

Prenatal Development 3 Trimester’s: 1 st, 2 nd & 3 rd 3 Periods (stages): Germinal, embryonic & fetal 38 weeks

Milestones of Prenatal Dev. Table 2.2 (p. 61) 1 st Trimester – weeks 1 to 12 (germinal/zygote, embryonic, & early part of fetal period) 2 nd Trimester - weeks 13 to 24 (fetal period) 3 rd Trimester - weeks 25 to 38 (fetal period)

Part 2

Stages of Prenatal Development Gestation- lasts about 38 wks Germinal Stage (zygote): First 14 days of the pregnancy Zygote implants into the uterus lining…

Stage of the Embryo 1)The endoderm layer- will develop into internal organs & glands

2) The ectoderm layer- become the parts of the body that maintain contact w/ the outside world: the nervous system;

3) The mesoderm layer- muscles, cartilage, bone, sex organs (reproductive sys), & the heart (circulatory sys).

The Prenatal Environment Amniotic sac- watertight membrane filled w/ fluid… The placenta-organ through which the organism/mother exchange materials.

The umbilical cord-links the organism to the placenta; it serves as a filter…

Stage of the fetus The main changes for the fetus are to develop further the already formed organ structures & increase in size & weight From 3- 4 mos., By 4 th mos. mother produces colostrum …

By 4 th mos. lanugo and covers the body and vernix is secreted.

Conception to Birth Start at 2 min; STOP at 5:52

Small Group Discussion How has your culture influenced the way a woman/man, experiences pregnancy (i.e. – beliefs, practices, traditions, etc.)? What about the father/partner?

The 9 th month- Pregnancy around the World pregnant-and-still-working-fields pregnant-and-still-working-fields Stop at 5 min 10 seconds

Teratogens  Non-genetic agents that can cause malformation in the embryo / fetus.  1930’s:  Mid 1940’s:  1960’s: