Chap. 2: Prenatal Development and Prenatal Care

What will the mesoderm become?

the muscles, bones, reproductive system, and circulatory system

What will the ectoderm become?

the skin, hair, nails, sensory organs, and nervous system

Outline the major milestones of the fetal period and when they take place.

weeks 9-12: genitals form and release sex hormones; fingernails, toenails, and taste buds develop; heartbeat audible with telescope

What structures form during the germinal period?

Zygote divides and forms blastocyst, which implants in uterus and begins forming the amnion, placenta, and umbilical cord.

George's father carries the recessive gene for sickle-cell anemia, and George's mother carries a normal dominant gene. Therefore, George has inherited _______________ from his parents.

a resistance to milaria

What are the three forms of genotype → environment effects?

passive, evocative, and active

Ellen carries the recessive gene for hemophilia, a disorder in which the blood does not clot properly. If Ellen had two children, a boy and a girl, and passed the recessive gene for the disorder to both children, which of her children would develop hemophilia if the father does not have hemophilia himself?

the boy

What will the endoderm become?

the digestive system and the respiratory system

There is a rumor that pregnant women should dramatically increase their caloric intake and "eat for two"; however, it is known that pregnant women need about ____ more calories than those who are not pregnant.

300

Your friend is pregnant and worried that she will gain weight. Having been extremely thin, she is planning to diet to maintain her figure. Considering what you have learned from your text, what is your advice to her?

Avoid dieting. It could lead to her baby being born preterm and having low birth weight.

Low iodine intake during pregnancy increases the risks of miscarriage, stillbirth, and abnormalities in fetal brain development. Since the 1920s the United States has required table salt to have iodine, which is a similar practice to many countries that have economic wealth and resources. In what county is the lack of iodine most likely still an issue for pregnant women?

Cambodia, which is a developing country.

Outline the major milestones of the embryonic period and when they take place.

During the first week of the embryonic period, the third week after conception, the embryonic disk forms three layers. The nervous system develops and by the end of week 3 part of the ectoderm forms the neural tube, which will eventually become the spinal cord and the brain. During week 5 buds for arms and legs appear. Fingers and toes lose their webbing by the end of week 8. By the end of the 8th week all the main body parts have formed and all of the main organs, except for the sex hormones. weeks 3-4: three layers form: the ectoderm, the mesoderm, and the endoderm. Neural tube develops and produces neurons. Heart begins beating. Ribs, muscles, and digestive tract form. weeks 5-8: arms and legs develop, then fingers and toes; placenta and umbilical cord function; digestive system develops; liver produces blood cells; embryo responds to touch.

When does implantation take place?

During the second week after contraception implantation occurs as the blastocyst becomes firmly embedded into the lining of the uterus.

After fertilization, the first 2 weeks of pregnancy is called _____.

Germinal

What is the last major organ system to develop during the fetal period?

Lungs

According to the text, when a pregnant mother becomes highly stressed a fetus may ______.

develop a faster heart rate and move more frequently

James was born with a __________ that included exceptional musical ability, but because he was never exposed to musical instruments or instruction, his musical ability was not apparent in his ____________. Correct Answer genotype; phenotype

genotype, phenotype

The embryonic disk forms from the _____ of the blastocyst and develops to become the embryo.

inner layer

For women who are pregnant, heavy lifting, strenuous physical exertion, and continuous standing can raise the risk of ______.

miscarriages, preterm birth, and stillbirth

Jack and Burton are identical twins, also called ____________ twins, and they were born with _______ of their genes in common.

monozygotic (MZ); 100%

During the embryonic period, the ectoderm develops to become ______.

skin, hair, nails, sensory organs, and nervous system

The _____ form from the outer layer of the embryonic disk.

skin, hair, nails, sensory organs, and nervous system