Chapter 21
Which of the following statements about the notochord is NOT correct?
The notochord gives rise to the spinal cord.
Which of the following is a correct statement?
The placenta secretes hormones including HCG and progesterone.
__________ stimulates the production of milk, whereas __________ causes ejection of milk from the breast.
Prolactin; oxytocin
Which of the following would be detrimental to the health of a neonate?
The ductus arteriosus stays open.
At __________, the circulatory, respiratory, and digestive systems function independently for the first time.
Birth
Which of the following terms describes the embryonic cell divisions that occur without cell growth in mammals?
Cleavage
By week eight of development, __________.
all the organs and organ systems are established
The placenta __________.
allows for the exchange of nutrients, gases, and antibodies between maternal and embryonic circulations
Possible activities of telomerase could be __________.
both stopping the aging process by rebuilding the telomeres and contributing to cancer by allowing tumor cells to continue dividing indefinitely
Which of the following is a critical organ system whose failure will very quickly lead to death?
cardiovascular
Brain growth is nearly complete (95% of its final size) by the end of __________.
childhood
Which of the following processes is the first to occur as a fertilized egg begins its journey down a uterine tube toward the uterus?
cleavage
Which is the correct order of events in embryonic development?
cleavage stage, morula formation, blastocyst formation, gastrulation, neurulation
Which of the following lists the correct order of structures through which a sperm must pass to accomplish fertilization?
corona radiata, zona pellucida, secondary oocyte plasma membrane
All of the following are theories regarding causes of aging, EXCEPT that __________.
cortisol production increases, and the stress response contributes to aging a decline in one critical body system induces parallel declines in others cells run out of telomeres and stop dividing cells can no longer repair themselves properly, and damage accumulates .....cortisol production increases, and the stress response contributes to aging
Which process is best described as individual cells taking on specialized forms and functions?
differentiation
True or false. Early animal development progresses through distinct stages: first the production of the zygote through fertilization, then cleavage, then the formation of the gastrula, and then the formation of the blastula.
false...The formation of a gastrula is the last stage in early animal development; the zygote undergoes cleavage to form a blastula, which eventually forms a gastrula.
Fertilization is most likely to occur if intercourse occurs during a time period __________.
from 2 days before ovulation to 1 day after ovulation
The aging of which organ or organ system is LEAST problematic during the normal aging process?
kidneys
Which of the following are MISMATCHED?
mesoderm: gastrointestinal tract lining neural groove: spinal cord placenta: chorion and endometrium urogenital groove: urethra.....mesoderm: gastrointestinal tract lining
Which of the following indicates the correct order of pre-embryonic developmental stages?
morula, blastocyst, embryonic disk
From the three primary germ layers, __________ is derived from the mesoderm.
muscle tissue
Which hormone plays a critical role in both childbirth and breast-feeding?
oxytocin
A sperm with a defective acrosome would NOT be able to __________.
penetrate the egg
Research on __________ supports the hypothesis that timing of cell death results from an internal cellular program that counts cell divisions
telomeres
Which of the following will result in fraternal twins?
the fertilization of two eggs by two different sperm
When discussing neurulation, we can say that ________.
the neural plate folds inward, forming the neural groove. The edges of the groove fuse to form the neural tube, which in turn gives rise to the brain and spinal cord
The ultimate human stem cell that divides mitotically to give rise to all adult tissues and organs is called the __________.
zygote
Mice with two X chromosomes who are also genetically engineered to express the SRY (Sex-determining Region Y) gene develop male genitalia. This demonstrates which of the following?
Gender is determined by the presence or absence of the SRY gene.
Which of the following occurs during days 7-14 of development?
Implantation occurs in the endometrium (inner lining) of the uterus.
Which of the following statements about the germ layers is NOT correct?
The endoderm gives rise to the nervous system.
A blastocyst is a large cluster of cells with a fluid-filled cavity. It consists of two parts: one that develops into the embryo and one that gives rise to part of the placenta. Name these two parts, and identify which part is which.
The inner cell mass develops into the embryo proper; the trophoblast develops into the placenta.
Which fetal hormone plays a role in initiating labor?
ACTH
Which of the following occurs first to begin labor?
ACTH is released by the mature fetal pituitary gland.
