mastering A&P ch. 27 group 1 modules 27.1-27.6

the extra-embryonic membranes that develop from from the endoderm and the mesoderm are the _________. yolk sac and the allantois. yolk sac and the amnion. allantois and the chorion. amnion and the chorion.

yolk sac and the amnion

the umbilical cord, or umbilical stalk, contains _________. the allantois, blood vessels, and yolk stalk the amnion, allantois, and chorion paired umbilical arteries and the amnion a single umbilical vein and the chorion

the allantois, blood vessels, and yolk stalk.

Gastrulation produces three germ layers. Which of the following is not one of those layers? the cells that will develop into the amnion. the cells that will develop into the embryo. the cells that will develop into the placenta. the cells will develop into chorion

the cells that will develop into the embryo.

Exchange between the embryonic and the maternal circulations occurs by diffusion across the syncytial and cellular trophoblast layers via __________. the chorionic blood vessels the allantois the yolk sac the umbilicus

the chorionic blood vessels

the chorion develops from the ____________. endoderm and the mesoderm mesoderm and the trophoblast trophoblast and the endoderm ectoderm and the mesoderm

mesoderm and the trophoblast

Gastrulation produces three germ layers. Which of the following is not one of those layers? endoderm blastocele mesoderm ectoderm

blastocele

a hollow ball of cells created by cleavage is called a morula gastrula blastocyst fetus

blastocyst

Which of the following is the term for the events that occur during the first two months of development after fertilization? fetal development gametogenesis embryological development postnatal development

embryological development

what event marks the onset of development? implantation meiosis fertilization embryo formation

fertilization

The term for what occurs when the blastocyst touches and grows into the endometrium is __________. implantation gastrulation placentation cleavage

implantation

Throughout embryonic and fetal development, metabolic wastes generated by the fetus are eliminated by their transfer to the __________. chorion amniotic fluid maternal circulation allantois

maternal circulation

what happens during the process of hatching? the fertilized egg becomes the new baby. the blastocyst contacts the uterine lining. the zygote begins to divide. the zona pellucida is shed from the blastocyst.

the zona pellucida is shed from the blastocyst.

which of the following is NOT one of the germ layers formed during gastrulation? trophoderm mesoderm endoderm ectoderm

trophoderm

Fertilization usually occurs in the uterine tube uterus vagina ovary

uterine tube

what is the meaning of the term gestation? first trimester development only second trimester development only all of prenatal development third trimester development only

all of prenatal development

what is the extra-embryonic membrane that gives rise to the urinary bladder? chorion placenta amnion allantois

allantois

the fusion of male and female pronuclei is termed _______. polyspermy oocyte activation fertilization amphimixis

amphimixis

which of the following forms the placenta? amnion chorion allantois yolk sac

chorion

a sequence of cell divisions that begin after fertilization is called cleavage gastrulation implantation placentation

cleavage

Which of the following is the term for the developmental events events that occur between the ninth week and birth? embryological development gastrulation fetal development postnatal development

fetal development

what is the "moment of conception"? fusion of the male and female pronuclei penetration of the sperm nucleus into the secondary oocyte. fusion of the sperm and oocyte membranes. binding of the sperm to the sperm receptors.

fusion of the male and female pronuclei.

what triggers the activation of the secondary oocyte? the presence of the sperm nucleus in the cytoplasm of the secondary oocyte. fusion of the sperm and secondary oocyte membranes. penetration of the sperm head through the oocyte membrane. multiple sperm contacting the membrane of the secondary oocyte.

fusion of the sperm and secondary oocyte membranes.

Germ-layer formation results from the process of __________. gastrulation embryogenesis parturition organogenesis

gastrulation

which of the following does NOT happen during oocyte activation? Cortical reaction prevents polyspermy. Enzymes are activated to increase the ovum's metabolic rate. Meiosis II is completed. The first cleavage is completed.

the first cleavage is completed