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