Ch. 18 Human Biology Review Q's

If a fetus contains an X and a Y chromosome but a defective SRY gene, they will develop into an anatomical female because testosterone is not present. into an anatomical male because testosterone is not present. into an anatomical female because testosterone is present. into an anatomical male because testosterone is present. into a hermaphrodite due to the presence of estrogen and testosterone.

A defective SRY gene would not allow the production of testosterone and the fetus would develop into a female.

Which of the following is not involved in the increase in blood volume in a pregnant woman? progesterone artery expansion renin-angiotensin-aldosterone mechanism an increase in blood oxygen levels sodium and water retention

All of these have an effect on increasing blood volume except the blood oxygen levels, which change little during pregnancy.

Which of the following is involved in the prevention of polyspermy? acrosome of the sperm depolarization of the egg's plasma membrane fusion of the sperm and egg nucleus changes within the corona radiata the number of chromosomes contained within the sperm

As soon as a sperm touches an egg, the egg's plasma membrane depolarizes. This prevents the binding of any other sperm.

The nervous system develops enough to permit reflex actions during which period of development? pre-embryonic embryonic, weeks 6-8 fetal, months 3-4 embryonic, weeks 2-3 embryonic, weeks 4-5

At 6-8 weeks, the nervous system is developed well enough to permit reflex actions. During the pre-embryonic stage there is no nervous system. During the embryonic weeks 2-3 and weeks 3-4, the nervous system is not developed enough to permit the reflex actions.

Which of the following is not true concerning the fetus during the third month of development? Bone begins to be replaced with cartilage in certain areas of the skeleton. The nose, eyes, and ears are present. Fingernails, nipples, eyelashes, eyebrows, and hair on the head appear. Head growth slows down as the rest of the body increases in length. It is possible to distinguish males from females.

At the beginning of the third month, cartilage begins to be replaced by bone as ossification centers appear.

Does a woman ovulate during pregnancy? Why or why not? No, because she doesn't have any more follicles in the ovaries. No, because negative feedback on the hypothalamus prevents new follicles from maturing. No, because the developing embryo prevents any new blastulas from implanting. Yes, because the uterine cycle continues to function. Yes, because the ovarian cycle continues to function.

B. No, because negative feedback on the hypothalamus prevents new follicles from maturing.

How are the pulmonary veins and the umbilical veins similar? They are both present in an adult human. They both carry blood to the lungs. They both connect to the superior vena cava. They both carry oxygen-rich blood. They both connect to the placenta.

Both the umbilical vein and the pulmonary veins carry oxygen-rich blood (which is unusual for veins).

Why would you predict that the blood carbon dioxide levels in a pregnant woman would fall? She has trouble breathing due to the expanding uterus. The fetus is removing carbon dioxide from her blood. The maternal oxygen levels are also falling. Pregnancy creates a favorable concentration gradient between the fetal and maternal blood. The bronchial tubes relax.

D. Pregnancy creates a favorable concentration gradient between the fetal and maternal blood.

Which of the following would be considered a poor health practice for a woman planning to get pregnant or already pregnant? updating all vaccinations treating all sexually transmitted diseases obtaining more folic acid eating enough to feed two people moderate exercise

D. eating enough to feed two people

When cells take on specific structure and function, this is called cleavage. growth. morphogenesis. differentiation. fertilization.

Differentiation occurs when cells take on a specific structure and function. Cleavage is when the zygote begins to divide. Growth is the increase in size of the cells. Morphogenesis is the shaping of the embryo. Fertilization is the union of the sperm and egg to form the embryo.

When does the mother first begin to feel the fetus move? 1-2 months 3-4 months 5-7 months 7-9 months 1-4 weeks

During the fifth through seventh months the mother begins to feel movement.

Which of the following develops into the male genital ducts? epididymis urogenital groove cloaca Mullerian ducts Wolffian ducts

E. Wolffian ducts The male genital ducts develop from the Wolffian ducts.

Which of the following problems is not associated with pregnancy? lordosis lower back pain gastrointestinal reflux incontinence impotence

E. impotence Impotence is a male problem and is not associated with pregnancy.

The ________ is the first embryonic membrane to appear, and it is the first site of ________. amnion, umbilical cord formation yolk sac, placenta development chorion, neural system development allantois, amniotic fluid formation yolk sac, blood cell formation

E. yolk sac, blood cell formation The yolk sac is the first embryonic membrane to appear and it is the first site of blood cell formation.

Embryonic development begins with fertilization. the first cell division. the development of the blastocyst. implantation. gastrulation.

Embryonic development begins at implantation.

An embryo at the 4-cell stage of development is almost twice the size of an embryo at the 2-cell stage of development. True False

FALSE Cleavage results in an increase in the number of cells without an increase in size of the embryo.

Most birth defects are due to the inheritance of an abnormal number of chromosomes. True False

FALSE Most birth defects are the result of poor health practices during pregnancy.

Estrogen is responsible for the onset and continuation of labor. True False

FALSE Oxytocin is responsible for the onset and continuation of labor.

The blood of the mother and the fetus mix in the placenta. True False

FALSE The blood of the mother and the fetus never mix because exchange takes place across the villi.

The embryonic disk becomes the inner cell mass after gastrulation. True False

FALSE The inner cell mass becomes the embryonic disk after gastrulation.

When the uterus begins to contract, it is almost time for the baby to be born. True False

FALSE The uterus has contractions throughout pregnancy.

At what point during development does the embryo form three germ layers? when it begins cleavage when the nervous system develops when it forms the gastrula when it forms the inner cell mass when it becomes recognizable as human

Gastrulation involves morphogenesis and the formation of three germ layers.

Which of the following is not a chief effect of progesterone? increased uterine blood flow relaxation of smooth muscle reduced uterine motility reduced maternal immune response to fetus low blood pressure

Increased uterine blood flow is a chief effect of estrogen

When cells begin to move in the embryo in relation to other cells, this is called cleavage. growth. morphogenesis. differentiation. fertilization.

Morphogenesis is the shaping of the embryo, and is first evident when certain cells move in relation to other cells. Cleavage is the division of the cells. Growth is the increase in size of the cells. Differentiation is when cells take on specific structures. Fertilization is the union of the sperm and egg.

Summarize the events that occur during each stage of birth

Stage 1 is when the uterine contractions of labor begin. The cervical canal slowly disappears as the uterus is pulled upward. The baby's head acts as a wedge to assist cervical dilation. The amniotic membrane will rupture during this stage. Stage 2 is when the uterine contractions increase in frequency and force. The baby's head will descend into the vagina. As the head is delivered the rest of the baby will follow. Stage 3 is when the placenta is delivered. Uterine muscular contractions shrink the size of the uterus and cause the placenta to be dislodged and expelled through the vagina

Fetal development includes the third through ninth months of development. True False

TRUE Fetal development follows embryonic development and lasts from the third through the ninth month of development.

The sex of an individual is determined at the moment of fertilization. True False

TRUE Sex is determined by the chromosomal make up (XX for females, XY for males) which is determined at the moment of fertilization.

The names of the extraembryonic membranes are derived from their function in animals that produce shelled eggs. True False

TRUE The names of these membranes are derived from their functions in birds

The amnion is to the amniotic fluid as the allantois is to the blood cell precursors. chorionic villi. umbilical blood vessels. amniotic cavity. yolk.

The amnion contains the amniotic fluid while the allantois contains the umbilical blood vessels.

The yolk sac of the chick provides nutrients to the developing embryo. What structure serves the same role in humans? chorion allantois yolk sac amnion zona pellucida

The chorion develops into the fetal half of the placenta and provides the embryo with nourishment and oxygen. The allantois develops into the umbilical arteries and veins. The yolk sac contains food for the developing embryo. The amnion contains protective fluid that cushions the embryo. The zona pellucida is the surrounding membrane of the egg prior to fertilization.

Which of the following is present in the fetus but not in an adult human? ductus arteriosus pulmonary vein left atrium superior vena cava internal iliac artery

The ductus arteriosus enables the blood to bypass the lungs, and closes at birth.

When does the heart begin to develop? week 1 week 3 week 5 week 7 week 9

The heart begins to develop in the third week and continues into the fourth week.

Which of these is associated with pre-embryonic development? morula embryonic disk gastrulation primary germ layers formation of the umbilical cord

The morula, a ball of cells, forms early during pre-embryonic development.

The nervous system is to the ectoderm as the skeleton is to the mesoderm. endoderm. chorion. allantois. blastula.

The nervous system develops from ectoderm and the skeleton develops from mesoderm

The first system in the body to become visibly differentiated during development is the digestive system. cardiovascular system. respiratory system. nervous system. reproductive system.

The nervous system is the first system to become visibly differentiated

Which of the following occurs during the embryonic stage of development? Chorion appears. Nose, eyes, and ears become noticeable. Testes descend into the scrotum. Heartbeat can be heard. Fingernails appear.

The nose, eyes, and ears are noticeable at about the 5th week

What occurs during stage 3 of labor? The cervix dilates. The baby is born. Effacement occurs. The amniotic sac ruptures. The placenta is expelled.

The placenta is expelled. The afterbirth is expelled during the third stage of birth

What structure produces progesterone and estrogen during pregnancy? placenta hypothalamus anterior pituitary posterior pituitary ovaries

The placenta is the source of progesterone and estrogen during pregnancy.

The umbilical arteries carry oxygen-rich blood to the developing fetus. oxygen-rich blood to the placenta. oxygen-poor blood to the developing fetus. oxygen-poor blood to the placenta. oxygen-rich blood to the mother.

The umbilical arteries carry oxygen-poor blood to the placenta. The umbilical veins carry the oxygen-rich blood to the fetus

Which of the following is not derived from the endoderm? epithelial lining of the digestive tract epithelial lining of the respiratory tract glands of the digestive tract lining of the urinary bladder urinary system

The urinary system forms from mesoderm.

The white, greasy, cheeselike substance that covers the fetus's skin is called lanugo. fontanels. vernix caseosa. foramen ovale. ductus arteriosus.

The vernix caseosa is a white, greasy, cheeselike substance that probably protects the skin from the amniotic fluid.

Which of the following is not associated with the egg? corona radiata acrosome zona pellucida cortical granule fertilization membrane

acrosome

The adhering follicular cells that surround the egg are called the pronuclei. zona pellucida. corona radiata. cortical granule cells. outer cell mass.

corona radiata

Which of the following gives the correct order of layers the sperm crosses when entering the egg? corona radiata, zona pellucida, oocyte plasma membrane zona pellucida, oocyte plasma membrane, corona radiata oocyte plasma membrane, corona radiata, zona pellucida corona radiata, oocyyte plasma membrane, zona pellucida zona pellucida, corona radiata, oocyte plasma membrane

corona radiata, zona pellucida, oocyte plasma membrane

Which of the following does not occur prior to or during stage 1 of labor? bloody show effacement uterine contractions breaking water dislodging of the placenta

dislodging of the placenta The disloding of the placenta does not occur until stage 3 of labor

At the end of the embryonic period, the embryo is about 12 inches long. True False

false At the end of the embryonic period, the embryo is approximately 1.5 inches long

Which part of the sperm contains the chromosomes? tail middle piece head cell membrane flagella

head

Where are the mitochondria located in the sperm? tail middle piece head nucleus cell membrane

middle piece

During fertilization, several sperm penetrate the corona radiata. True False

true