(1) the ovum passes through the oviduct by beating action of epithelial cilia (2) muscular
contractions of the tubal wall assist the ovum passage (3) it takes the oocyte 25 minutes to
reach the ampulla (4) the ovum is viable during 24 hours after ovulation
15. The following statements regarding the fertilization are true:
(1) occurs in the oviduct ampulla (2) is part of progenesis (3) requires about 24 hours (4)
completes the initial period
16. The following statements regarding the sperm capacitation are true:
(1) is removal of the glycoprotein coat from the plasma membrane over the acrosome (2)
spermatozoa are capacitated by substances of the female genital tract (3) lasts for 7 hours
(4) acrosome reaction occurs after capacitation
17. The following statements regarding the cortical reaction are true:
(1) cortical granules open and release their enzymes (2) physiochemical characteristics of
the zona pellucida change, and the zona reaction is formed (3) zona reaction is
impermeable to spermatozoa (4) zona reaction facilitates oocyte penetration
18. The following statements regarding the events of fertilization after penetration
are true:
(1) the second meiotic division is completed (2) the sperm head enlarges to form the male
pronucleus (3) male and female pronuclei approach, contact, and lose their membranes
(4) chromosomes intermingle at metaphase of the first zygote division
19. The following statements regarding the cleavage are true:
(1) blastomeres do not differentiate (2) through the first divisions blastomeres retain
totipotentiality (3) initially, cleavage is under control of maternal macromolecules (4) later,
development depends on the embryonic genome
20. The following statements regarding the neurulation are true:
(1) includes the formation of the neural plate, neural groove, neural tube, and neural crest
(2) the neural tube is the primordium of the central nervous system (3) the neural crest
gives rise to spinal and autonomic ganglia, Schwann cells, meningeal covering of the
brain, pigment cells, and the adrenal medulla (4) dermotome induces overlying ectoderm
to form the neural plate
21. The following statements regarding the mesoderm differentiation are true:
(1) paraxial mesoderm divides into somites (2) intermediate mesoderm forms the somite
cord (3) lateral mesoderm is divided into somatopleure and splanchnopleure (4)
somatopleure and splanchnopleure surround the coelom
22. The following statements regarding the germ layer differentiation are true:
(1) some mesoderm cells migrate to form the mesenchyme (2) mesenchyme gives rise to
blood, all types of connective tissue, smooth muscle cells, blood vessels, microglia, and
the endocardium (3) surface ectoderm differentiates into the epidermis, hair, nails, skin
glands, mammary glands, salivary glands, and tooth enamel (4) endoderm gives rise to
the digestive tract epithelium, liver, pancreas, and lung epithelium
23. The following statements regarding the folding of the human embryo are true:
(1) longitudinal and transverse folds are formed in the early embryonic period (2) folds
convert the flat embryonic disk to a C-shaped cylindrical embryo (3) folding separates the
embryo body from the yolk sac and closes the primitive gut (4) folding results in the
formation of the human amnion
24. Differentiation is:
(1) the choice of a cell’s particular fate (2) development of specialized cell types from stem
cells (3) cell capabilities have not yet been realized (4) changes in the cell structure and
biochemistry for the cell to perform distinctive functions
25. The following statements regarding the cell potentialities are true:
(1) the zygote is totipotential (2) stem cells are pluripotential (3) immature descendants of
stem cells are usually oligopotential (4) mature cells are unipotential