Chapter 29 Development
What term refers to the fusion of two haploid gametes, each containing 23 chromosomes, producing a zygote that contains 46 chromosomes? fertilization ovulation differentiation cleavage
fertilization
The inner cell mass of the blastocyst will A) form the placenta. B) form the morula. C) form the embryo. D) form blood vessels of the placenta. E) provide nutrients for early growth.
form the embryo.
What is the developmental fate of "9"? forms the placenta forms the chorion forms the embryo forms the parietal decidua forms the trophoblast
forms the embryo
At what stage of embryogenesis do the three germ layers form? extraembryonic stage gastrulation neural tube formation blastocyst
gastrulation
The term ________ refers to the time spent in prenatal development. micturition transformation cleavage parturition gestation
gestation
A blastocyst is a(n) A) extraembryonic membrane. B) solid ball of cells. C) hollow ball of cells. D) portion of the placenta. E) origin of the urinary bladder.
hollow ball of cells.
Sperm release ________ to break down the bonds between adjacent follicle cells surrounding the oocyte. hyaluronidase glucose relaxin calcium zonal inhibiting proteins
hyaluronidase
The uterine epithelium is broken down by the enzyme, relaxin. urase. proteoglycan. acrosin. hyaluronidase.
hyaluronidase.
Identify the process occurring at the structure labeled "13." gastrulation fertilization implantation migration ovulation
implantation
The penetration of the endometrium by the blastocyst is referred to as embryogenesis. implantation. fertilization. cleavage. placentation.
implantation.
During early development, the Y chromosome produces a substance called "testis determining factor" (TDF) that causes the indifferent gonad to become a testis. This would be an example of differentiation. induction. capacitation. predilection. activation.
induction
The transfer of genetically determined characteristics from generation to generation is termed phylogeny inheritance differentiation development maturity
inheritance.
What is found in the area indicated by the arrow? maternal blood yolk fetal blood amniotic fluid
maternal blood
Which embryonic germ layer forms connective tissues such as bone and cartilage? trophoderm mesooderm endoderm ectoderm epiderm
mesooderm
The region known as the primitive streak is the site of migration of mesodermal cells to form the endoderm. endoderm formation. migration of ectodermal cells to form the mesoderm. amnion formation. ectoderm formation.
migration of ectodermal cells to form the mesoderm.
After three days of cleavage divisions, the pre-embryo is a solid ball of blastomeres. What is the name of the pre-embryo at this stage? morula blastocyst inner cell mass zona pellucida
morula
The solid ball of cells that has been likened to a mulberry is called a blastocyst. morula. blastula. gastrula. chorion.
morula.
The mesoderm forms the brain. respiratory epithelium. epidermis. muscle. the lining of the digestive tract.
muscle.
Ectoderm is to ________ as mesoderm is to ________. muscle tissue; neural tissue neural tissue; muscle tissue mesoderm; endoderm cardiovascular system; neural tissue neural tissue; epithelial tissue
neural tissue; muscle tissue
The ectoderm forms the lining of the digestive tract. neural tissues. muscle. blood. the urinary system.
neural tissues.
The site where fertilization normally occurs is in the fimbrae. outer one-third of the uterine tube. uterine wall near the fundus. union of the vagina and uterus. cervix.
outer one-third of the uterine tube.
Fertilization stimulates the oocyte to enter meiosis II and the fertilized oocyte is called a(n) primary oocyte. ovum. polar body. oogonium. secondary oocyte.
ovum
The ________ is the portion of the endometrium not in contact with the chorion. trophoblast parietal decidua capsular decidua functional decidua allantois
parietal decidua
During embryonic development, which structure temporarily takes on the function of the lungs? yolk sac placenta endometrium myometrium
placenta
Identify the structure labeled "4." basal decidua endometrium chorion placenta amnion
placenta
The processes that occur in the embryonic period are cleavage and placentation. placentation and embryogenesis. implantation and embryogenesis. implantation and placentation. cleavage and implantation.
placentation and embryogenesis.
The period of gestation when organs and organ systems complete most of their development and the fetus looks distinctly human is the ________ trimester. first second third
second
Which of these pairs of terms is mismatched? third trimester - largest size gain first trimester - formation of trachea and lungs first trimester - placentation second trimester - embryogenesis
second trimester - embryogenesis
Which of the following is not part of oocyte activation? release of calcium ion from smooth ER membrane depolarization influx of sodium iondischarge of exocytotic vesicles adjacent to the oocyte membrane softening of the zona pellucida
softening of the zona pellucida
Which of the following oocyte processes is NOT activated by sperm penetration? completion of meiosis IImembrane depolarization discharge of exocytotic vesicles softening of the zona pellucida
softening of the zona pellucida
The uterine epithelium is broken down by which structure of the blastocyst? blastocoele amnion cytotrophoblast syncytiotrophoblast allantois
syncytiotrophoblast
The embryo becomes a fetus at the end of the eighth week. the end of the first week. the end of the second trimester. the end of the second week. the end of the third trimester.
the end of the eighth week.
The developmental period that is the period of all embryological and early fetal development is the first trimester. the third trimester. the second trimester. adolescence. infancy.
the first trimester
During amphimixis... the male and female pronuclei fuse. the ovum finishes meiosis II. gametes are formed. sperm become haploid. meiosis occurs.
the male and female pronuclei fuse
The zygote forms when __________. sperm penetrates the oocytethe male and female pronuclei fuse the spermatozoan contacts the oocytethe female pronucleus completes meiosis II
the male and female pronuclei fuse
The endoderm forms blood. skin. muscle. the urinary bladder. neural tissue.
the urinary bladder.
The period of gestation that is characterized by rapid fetal growth and fat deposition is the ________ trimester. first second third
third
The period of gestation that is characterized by rapid growth and fat accumulation is the __________ trimester. third postnatal first second
third
During gastrulation, cells from the hypoblast move to the epiblast. the neural tube closes. the blastomeres fuse. the placenta penetrates the endometrium. three germ layers are formed.
three germ layers are formed.
The human gestation period consists of two trimesters of 2 months each. three trimesters of 3 months each. two trimesters of 1 month each. fertilization and one trimester. three trimesters of 1 month each.
three trimesters of 3 months each.
During implantation, the A) trophoblast erodes a path through the endometrium. B) inner cell mass begins to form the placenta. C) maternal blood vessels in the endometrium are walled off from the blastocyst. D) entire trophoblast becomes syncytial. E) inner cell mass is temporarily deprived of nutrients.
trophoblast erodes a path through the endometrium.
The outer layer of the blastocyst that can penetrate the endometrium is the blastula. archegonium. gastrula. trophoblast. chorion.
trophoblast.
Shortly after gastrulation, the body and organs of the embryo begin to form. This process is called cleavage. placentation. germination. embryogenesis. implantation.
embryogenesis.
The process by which a viable embryo is formed is called morphogenesis. blastogenesis. embryogenesis. gametogenesis. organogenesis.
embryogenesis.
Which embryonic germ layer forms the linings of the respiratory and digestive tracts? ectoderm trophoderm endoderm epiderm mesoderm
endoderm
Which of the given cells represents the earliest stage after fertilization? A B C D
A
Which of the images shows the third week of gestation? A B C D
A
Which of the labels in the figure indicates the growing population of mesoderm cells? A B C D
A
Which of these processes occurs after oocyte activation and the completion of meiosis II? The nucleus of the sperm cell swells. The nuclear material within the ovum reorganizes into a female pronucleus. The head, neck, and middle pieces of the sperm cell break down. All of the listed processes occur after oocyte activation and the completion of meiosis II.
All of the listed processes occur after oocyte activation and the completion of meiosis II.
________ are nearly identical cells that are produced by early cleavages. Blastomeres Gastrulas Blastulas Morulas Amnions
Blastomeres
Which of the following statements concerning development is false? Differences in a cell's cytoplasmic makeup affect the cell's genetic activity. Cells release molecules that affect the developmental process of neighboring cells. Each blastomere in the blastocyst receives exactly the same cytoplasmic composition. The developing oocyte receives molecules that affect development from the surrounding granulosa cells. The term induction refers to the chemical interplay between developing cells.
Each blastomere in the blastocyst receives exactly the same cytoplasmic composition.
Which of the following is false concerning the allantois? It projects into the umbilical cord. It acts as the fetal bone marrow. It stores nitrogenous wastes. Part will develop as the urinary bladder. It derives partly from endoderm.
It acts as the fetal bone marrow.
During development, the placenta secretes several hormones, including progesterone and estrogen. But what would happen if the fetus is male? Placental secretion of estrogen and progesterone would cause the male fetus to become feminized. Placental secretion of estrogen and progesterone would cause the male fetus to be sterile. Placental secretion of estrogen and progesterone would have no effects on the developing fetus. Placental secretion of estrogen and progesterone would cause the male fetus to develop smaller than normal external genitalia.
Placental secretion of estrogen and progesterone would have no effects on the developing fetus.
Which of the following statements about the first trimester is false? The events that occur during the first trimester are very complex. During this trimester, cleavage, implantation, placentation and embryogenesis occur. It consists of 10 developmental weeks. Only about 40 percent of conceptions survive the first trimester. The fetus gains the most weight during the first trimester.
The fetus gains the most weight during the first trimester.
Polyspermy results in Polyspermy results infetuses with different fathers. chimeric adults. a nonfunctional zygote. haploid individuals. twins.
a nonfunctional zygote.
After fertilization, the first cell division is completed within the hour. in 12 hours. within a few seconds. about 6 hours later. about 30 hours later.
about 30 hours later.
How many days after fertilization will it take the pre-embryo to reach the point indicated by the red arrow? 1 day 2-3 days about 5 days 7-10 days
about 5 days
Identify the stage labeled "8." early morula trophoblast blastomere advanced morula zygote
advanced morula
The umbilical cord contains the yolk sac, the placental blood vessels and the chorionic villi. allantois. amnion. chorion. decidua.
allantois.
The extraembryonic membrane that forms a fluid-filled sac is the decidua. amnion. yolk sac. chorion. allantois.
amnion.
The fetus develops within a membranous cavity called the __________. allantois amniotic cavity chorion decidua parietalis
amniotic cavity
A space opens within the inner cell mass that will form the chorion. lacunae. allantois. blastocoele. amniotic cavity.
amniotic cavity.
The separation between the inner cell mass and the trophoblast forms a fluid-filled chamber called the placenta. allantois. chorion. amniotic cavity. yolk sac.
amniotic cavity.
The inner cellular layer of trophoblast that remains intact inside the blastocyst is termed the morula. synctiotrophoblast. cytotrophoblast. lacunae. amnion.
cytotrophoblast.
Placental functions are concentrated in a disc-shaped area in the endometrium called the capsular decidua. trophoblast. allantois. basal decidua. parietal decidua
basal decidua.
Where in the embryo does mesoderm first appear? around the trophoblast above the epiblast in the chorionic villi between the cell layers of the inner cell mass within the blastocoele
between the cell layers of the inner cell mass
The hollow cavity within the blastocyst is the blastocoele. blastula. gastrula. ootid. trophoblast.
blastocoele.
Identify the stage labeled "12." trophoblast late morula blastocyst early morula zygote
blastocyst
Implantation of the __________ occurs about seven days after __________. blastocyst; fertilization zygote; fertilization zygote; ovulation blastocyst; ovulation
blastocyst; fertilization
Identify the structures labeled "6." polar bodies cytotrophoblast blastomeres syncytiotrophoblast trophoblast
blastomeres
The almost identical cells produced by cleavage divisions are called blastomeres. telomeres. centromeres. myosomes. somal cells.
blastomeres.
Which of the following events does NOT occur during the third trimester of prenatal development? accumulation of adipose tissue organ systems fully functional blood formation begins in the liver large weight gain
blood formation begins in the liver
The trophoblast induces endometrial capillaries to __________. invade the inner cell mass penetrate the chorion invade the trophoblast break down and form lacunae
break down and form lacunae
Under the influence of the trophoblast, maternal blood vessels in the endometrium break down and form sinuses or lacunae. attach to the inner cell mass. increase in size and penetrate the blastocyst. form a capillary network in the trophoblast.disappear.
break down and form sinuses or lacunae.
In ________, implantation occurs somewhere other than in the uterus. placenta previa ectopic pregnancy hydramnios abortion spontaneous abortion
ectopic pregnancy
Identify the structure labeled "8." amnion placenta capsular decidua basal decidua chorion
capsular decidua
The part of the endometrium that covers the implanted embryo and lacks chorionic villi is the albicans decidua. capsular decidua. functional decidua. parietal decidua. basal decidua.
capsular decidua.
The extraembryonic membrane that forms the fetal portion of the placenta is the decidua. amnion. yolk sac. chorion. allantois.
chorion.
The mesoderm and the trophoblast combine to form the amnion. inner cell mass. amniotic sac. allantois. chorion.
chorion.
The process that divides different portions of the zygote's cytoplasm among blastomeres is called __________. embryogenesis placentation fertilization cleavage
cleavage
The processes that occur in the pre-embryonic period are cleavage and implantation. placentation and embryogenesis. implantation and placentation. implantation and embryogenesis. cleavage and placentation.
cleavage and implantation
The process of cell division that divides the cytoplasm of the zygote among blastomeres is called blastulation. embryogenesis. cleavage. placentation. implantation.
cleavage.
The layer of follicle cells that surround the unfertilized egg is called the zona pellucida. tunica follicularis. functional zone. Graafian follicle. corona radiata.
corona radiata.
Block to polyspermy is prevented by the ________ reaction. gamete gollumina metabolic cortical polarity
cortical
The gradual modification of an organism from conception to maturity is called __________. fertilization differentiation development embryonic development
development
The gradual modification of anatomical structures and physiologic characteristics from fertilization to maturity is termed ontogeny transformation gametogenesis disablement development
development
The formation of different types of cells required in development, or ________, occurs through selective changes in genetic activity. deployment differentiation cupellation gametogenesis phylogeny
differentiation
The process that results in the formation of different cell types occurring through selective changes in genetic activity that causes some genes to be turned off, while others are turned on is called __________. development conception fertilization differentiation
differentiation
Which of these is NOT a stage in development? embryonic development prenatal development differentiation postnatal development
differentiation
During gastrulation the three germ layers are formed. Which germ layer will ultimately give rise to all of the neural system? mesoderm endoderm ectoderm allantois
ectoderm
The epidermis and accessory structures of skin form from which germ layer? mesoderm epiderm ectoderm trophoderm endoderm
ectoderm
Which embryonic germ layer forms the brain and spinal cord? ectoderm trophoderm endoderm mesooderm epiderm
ectoderm
Blood flows from the fetus to the placenta through paired uterine arteries. iliac veins. umbilical arteries. uterine veins. umbilical vein.
umbilical arteries.
The ________ is formed by the allantois, blood vessels, and yolk sac. umbilical cord chorioallantoic membrane trophoblast amnion chorion
umbilical cord
Which of the following is not one of the extraembryonic membranes? allantois umbilical cord yolk sac amnion chorion
umbilical cord
Oxygenated blood from the placenta returns to the fetus in the allantois. umbilical arteries. umbilical vein. umbilical capillaries. decidua capsularis.
umbilical vein
Sperm cannot fertilize an oocyte until they undergo capacitation.are in the vagina for 3 days. undergo meiosis. are activated by sustentacular cells of the vagina. lose their flagellum.
undergo capacitation.
The extraembryonic membrane that forms blood is the allantois. decidua. amnion. yolk sac. chorion.
yolk sac.
The primary nutrient source for early embryonic development that later becomes an important site for blood formation is the yolk sac. placenta. amniotic fluid. basal decidua. umbilical vein.
yolk sac.
The cell that directly results from the fusion of a secondary oocyte and a single sperm is called a(n) ootid. gastrula. zygote. blastula. morula.
zygote.