prenetal development

prenetal development

chapter 15.1

Multiple Choice

The female sex cell and sex hormones

• egg cell - testosterone

• sperm - testosterone

• egg cell - estrogen

• zygote - estrogen

pregnancy

9 month or 40 weeks

Stages of Prenatal Development

There are three stages of prenatal development: Zygote, Embryo, Fetus

Stage 1: Zygote

• This stage begins at conception and lasts until the zygote is implanted in the mother’s uterus.

• Roots grow from the zygote into the wall of the uterus where they can receive nutrients from the mother’s blood.

• Length of time: First two weeks of pregnancy.

Stage 2: Embryo

• Embryo is attached to the mother by the umbilical cord, which reaches from the embryo’s stomach to the wall of the uterus.

• Length of time: 3rd through the 8th week of development.

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Stage 3: Fetus

• Body parts, organs and systems that were formed during the embryo period will become much more developed and begin to function.

• Length of time: 8th week until term of delivery.

First Trimester

• The most critical and greatest time of risk for birth defects

• Physical feature and organs form, heart beats and brain waves begin

• Gains weight

Second Trimester

• Increased organ development

• Physically the easiest trimester on the mother

Third Trimester

• Mom could feel discomforts of pregnancy

• Builds antibodies the last month to help the baby have a healthier

• Dropping movement of the baby in a head-down position in preparation for delivery

(52) Pregnancy 101 | National Geographic - YouTube

interesting fact

• elephants carry their babies for about 600-660 days

• orangutans are caring their kids for six to seven years

second part

• Female kangaroo has 3 vaginas which lead to 2 uteri. The outer 2 vaginas are for sexual intercourse and collecting sperm and the third one is exclusively meant for giving birth

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• A chipmunk can give birth every 40-45 days

(52) Having a Baby: Stages of Pregnancy - YouTube