Chapter 5

Question 1

a thick fibrous lining, made up of several layers,that helps to protect the fetus and forms the inner part of the sac in which the fetus grows.

Answer 1

amnion

Question 2

or conceptus, results when an ovum and a spermatozoon unite. The zygote has the full complement of 46 chromosomes, arranged in 23 pairs.

Answer 2

zygote

Question 3

a clear gelatinous substance that gives support to the cord and helps prevent compression of the cord, which could impair blood flow to the fetus.

Answer 3

Wharton’s jelly

Question 4

from the Greek terato,meaning monster, and genesis,meaning birth; an agent or influence that causes a defect or disruption in the prenatal growth process. The effect of a teratogen depends on when it enters the fetal system and the stage of differentiation of the organs or organ systems at that time. Generally,the fetus is most vulnerable to teratogens during the first trimester.

Answer 4

teratogen

Question 5

the solid cell cluster that forms about 3 days after fertilization, when the total cell count has reached 32.

Answer 5

morula

Question 6

identical twins that are derived from one zygote; one egg and one sperm divide into two zygotes shortly after fertilization.

Answer 6

monozygotic

Question 7

the specialized fluid that fills the amniotic cavity and serves to protect the fetus.

Answer 7

amniotic fluid

Question 8

the structure that forms about 5 days after fertilization when the dividing cell mass develops a hollow, fluid-filled core.

Answer 8

blastocyst

Question 9

a second layer of thick fibrous tissue that surrounds the amnion.

Answer 9

chorion

Question 10

finger-like projections that extend out from the chorion giving it a rough appearance.

Answer 10

chorionic villi

Question 11

the process of mitotic division performed by the zygote.

Answer 11

cleavage

Question 12

the endometrium that has changed to support a pregnancy.

Answer 12

decidua

Question 13

fraternal twins that develop from separate egg and sperm fertilization’s.

Answer 13

dizygotic

Question 14

prenatal blood vessel between the pulmonary artery and the aorta that closes functionally within the first 3 or 4 days of life.

Answer 14

ductus arteriosus

Question 15

prenatal blood vessel between the umbilical vein and the inferior venacava; does not achieve complete closure until the end of the second month of life.

Answer 15

ductus venosus

Question 16

occurs in a fallopian tube is a tubal pregnancy. Usually tubal pregnancies are caused by blockage or scarring of the fallopian tubes, from either infection or trauma, such as a tubal ligation reversal.
As the embryo grows in the confined space of the fallopian tube, it causes the tube to dilate. The tube will eventually rupture if the condition remains undetected.If the tube ruptures, hemorrhage into the peritoneal cavity can lead to maternal death. Surgical removal of the affected tube and the products of conception is the most common treatment.

Answer 16

ectopic pregnancy

Question 17

the developing conceptus, from weeks 2 through 8.

Answer 17

embryo

Question 18

term for the organism after it has reached the eighth week of life and acquires a human likeness.

Answer 18

fetus

Question 19

opening between the left and right atria of the fetal heart that closes with the first breath.

Answer 19

foramen ovale

Question 20

the formation and development of gametes or germ cells by the process of meiosis.

Answer 20

gametogenesis

Question 21

Once a single sperm has penetrated the thick membrane that surrounds the ovum called the ___ _____ a chemical reaction occurs that causes the ovum to become impenetrable to other sperm

Answer 21

Zona pellucida