CH 2 biological beginnings

Regarding the periods of prenatal development, which of the following statements is true? 1. The embryonic period begins in the first trimester and ends in the middle of the second trimester. 2. The germinal period corresponds to the first trimester, the embryonic to the second, and the fetal period occurs during the third trimester. 3. The germinal, embryonic, and fetal periods all begin during the first trimester. 4.The fetal period begins in the second trimester of pregnancy.

3. The germinal, embryonic, and fetal periods all begin during the first trimester.

Which of the following is true of the second stage of birth? The placenta detaches. The cervix stretches and opens. The baby's head moves through the birth canal. It lasts an average of 6 to 12 hours.

The baby's head moves through the birth canal.

In the third stage of birth, the placenta, umbilical cord, and other membranes are expelled from the uterus. This stage of birth is called the

afterbirth

The developing embryo floats in the______, which resembles a bag or an envelope and contains a clear fluid.

amnion

The life-support system that contains a clear fluid in which the developing embryo floats is known as the ______.

amnion

Research indicates that high doses of nonprescription ______ can be harmful during pregnancy.

aspirin

Which of the following are potential causes of infertility? Select all that apply: blocked fallopian tubes the woman does not ovulate ova lack motility low sperm production

blocked fallopian tubes the woman does not ovulate low sperm production

The formation of a connection, especially a physical one, between parent and infant shortly after birth is known as

bonding

The embryo's outermost layer, which will become the nervous system and brain, sensory receptors, and skin parts, is known as the ______.

ectoderm

When couples experience infertility, the problem may lie with ______.

either the man or the woman

After the blastocyst attaches to the uterine wall, the mass of cells is known as the ______.

embryo

Between two and eight weeks post-conception, the developing mass of cells is called a(n)____

embryo

The ______ is the inner layer of embryonic cells, which will develop into the digestive and respiratory systems.

endoderm

The lower layer of embryonic cells, which will develop into the digestive and respiratory system, is called the

endoderm

Which prenatal period lasts about seven months?

fetal

The prenatal period that lasts about seven months in typical pregnancies, beginning two months after conception, is the

fetal period

Interpreting the results of adoption and twin studies is difficult because of the complexities of ______.

heredity-environment correlations

Approximately 11 to 15 days after conception, ______ takes place.

implantation

The attachment of the zygote to the uterine wall is referred to as ______.

implantation

In general, exposure to teratogens has a more serious impact when ______.

it occurs earlier in pregnancy

_______care is a NICU procedure that involves skin-to-skin contact in which the baby, wearing only a diaper, is held upright against the parent's bare chest.

kangaroo

The three stages of birth are not of equal length; the first stage is ______ than the others

longer

The middle layer of the embryo, which will become the circulatory system, bones, and muscles, is called the ______.

mesoderm

The ______ is a disk-shaped group of tissues in which small blood vessels from the mother and the offspring intertwine but do not join.

placenta

The umbilical cord contains two arteries and one vein, and it connects the baby to the ______.

placenta

the_____is a life-support system that consists of blood vessels from the mother and offspring that intertwine but don't join.

placenta

Ultrasound _____uses high-frequency sound waves directed toward the pregnant woman's abdomen to produce a visual representation of the fetus.

sonography

Mothers who drink alcohol heavily during pregnancy can cause their offspring to exhibit fetal alcohol ______disorders, or FASD, a cluster of abnormalities and problems.

spectrum

Any agent that can potentially cause cognitive, behavioral or physical harm to the developing embryo or fetus is a(n) ______.

teratogen

The severity and type of damage to an embryo is influenced by the dose, genetic susceptibility and _____ of exposure to a teratogen.

time

Prenatal development can be described in terms of equal three-month time periods called

trimesters

The outer layer of cells surrounding a blastocyst that eventually provides nutrition and support for the embryo is called the ______.

tropoblast

Normally conducted seven weeks into the pregnancy, ______ is used to detect structural abnormalities in the fetus and when used later in the pregnancy can help determine whether the baby is a boy or a girl.

ultrasound sonography

Consisting of two arteries and one vein, the _____ _____ connects the baby to the placenta.

umbilical cord