Mastering A&P 2
Review the sequence of events involved in sperm penetration of the secondary oocyte in Focus Figure 28.1. Place the events of sperm penetration leading to fertilization in the correct sequence, from left to right and without overlapping any steps.
Correct After sperm penetration, the secondary oocyte completes meiosis II, forming the ovum. Fertilization occurs in the uterine tube when chromosomes of the sperm (male) and ovum (female) pronuclei combine to form a zygote.
Drag and drop the labels onto the figure to identify the structures in the fetus.
Correct The umbilical vessels transport blood between the fetus and placenta, whereas the ductus arteriosus and ductus venosus help blood bypass the fetal lungs and liver, respectively. The foramen ovale is located in the heart and serves to shunt blood from the right atrium to the left atrium, bypassing the lungs.
__________ occurs when a woman has a deformed or male-like pelvis, resulting in prolonged and difficult labor; this condition can lead to fetal brain damage, ultimately causing cerebral palsy or epilepsy. Dyspnea Parturition Preeclampsia Dystocia
Dystocia If a woman has a deformed or male-like pelvis, labor may be prolonged and difficult. This condition is called dystocia. Besides extreme maternal fatigue, another possible consequence of dystocia is fetal brain damage, resulting in cerebral palsy or epilepsy.
After DNA replication, each individual chromosome becomes a homologous pair. -True -False
False Correct After DNA replication, each chromosome is composed of two sister chromatids.
What is the role of the granulosa cells in the ovarian cycle? -Granulosa cells become the secondary oocyte once the antrum is formed. -Granulosa cells guide the development of the oocyte. -Granulosa cells release LH to trigger ovulation. -Granulosa cells produce progesterone. Submit
Granulosa cells guide the development of the oocyte. Correct Granulosa cells are directly connected to the oocyte by gap junctions, allowing for direct communication between the oocyte and granular cells. These cells guide each other's development.
Which of the following statements about the foramen ovale is FALSE? It is one of the shunt systems encountered by blood entering and leaving the heart before birth. It is an opening in the interatrial septum. It allows blood to pass directly from the right atrium into the left ventricle. It serves to bypass the nonfunctional lung.
It allows blood to pass directly from the right atrium into the left ventricle. The foramen ovale allows blood to pass from the right atrium into the left atrium.
What is the fate of the corpus luteum if pregnancy occurs? -It secretes progesterone and some estrogen for about three months. -It produces progesterone and some estrogen for about 10 days and then degrades. -It continues to stimulate the development of the oocyte until ovulation can occur. -It implants into the uterine wall to begin pregnancy. Submit
It secretes progesterone and some estrogen for about three months. Correct It implants into the uterine wall to begin pregnancy. Submit
What is the function of the hormone hCG (human chorionic gonadotropin)? It inhibits the production of estrogen and progesterone by the ovary. It stimulates the production of FSH by the pituitary. It increases to high levels near birth, helping initiate the birth process. It causes the uterine lining to slough off or shed to maintain pregnancy. It signals the corpus luteum to continue producing estrogen and progesterone to maintain the pregnancy.
It signals the corpus luteum to continue producing estrogen and progesterone to maintain the pregnancy. right answer feedback:hCG from the fetal trophoblast cells signals the corpus luteum of the ovary to continue producing estrogen and progesterone, which maintains the endometrium and prevents menstruation.
__________ and __________ are both hormones and powerful uterine muscle stimulants that cause contractions to become more frequent and more vigorous. Relaxin; oxytocin Estrogen; progesterone Human chorionic gonadotropin; relaxin Oxytocin; prostaglandins
Oxytocin; prostaglandins As birth nears, certain fetal cells begin to produce oxytocin, which causes the placenta to release prostaglandins. Both hormones are powerful uterine muscle stimulants that cause contractions to become more frequent and more vigorous.
Which of the following is FALSE regarding the vagina of an adult female? -The vagina is also called the birth canal. -The pH of the adult vagina is alkaline. -The vaginal mucosa lacks glands. -The mucosa of the vagina is stratified squamous epithelium.
The pH of the adult vagina is alkaline. Correct The pH of the vagina is acidic
An Apgar score of 8 to 10 indicates a healthy baby. True False
True An Apgar score of 8 to 10 indicates a healthy baby.
A weight gain of approximately 13 kg (about 28 lb) usually occurs during pregnancy. True False
True Because some women are over- or underweight before pregnancy begins, it is almost impossible to state the ideal or desirable weight gain. However, summing up the weight increases resulting from fetal and placental growth, increased size of the maternal reproductive organs and breasts, and greater blood volume during pregnancy, a weight gain of approximately 13 kg (about 28 lb) usually occurs
By the end of the third month of pregnancy, the placenta is usually fully functional as a nutritive, respiratory, excretory, and endocrine organ. True False
True The placenta is usually fully functional as a nutritive, respiratory, excretory, and endocrine organ by the end of the third month of pregnancy.
Human chorionic gonadotropin (hCG) levels spike within the first two months of pregnancy and then sharply decline by four months. True False
True Usually detectable in the mother's blood one week after fertilization, blood levels of human chorionic gonadotropin (hCG) continue to rise until the end of the second month. Then blood levels decline sharply to reach a low value by four months, a situation that persists for the remainder of gestation.
The heart begins to beat in the developing offspring __________. at about 3 ½ weeks at 3 to 4 months at birth at conception when it becomes a fetus
at about 3 ½ weeks right answer feedback:The heart begins to beat at about 3 ½ weeks. All organ systems are laid down in the embryonic period.
Implantation is completed after the __________. yolk sac forms nervous system forms amnion has formed blastocyst is entirely surrounded by endometrium corpus luteum deteriorates
blastocyst is entirely surrounded by endometrium right answer feedback:Implantation, which takes about a week, is completed after the blastocyst is entirely surrounded by endometrium (typically 12 days after ovulation).
Which of the following structures is/are formed from ectodermal tissues? gonads cartilage brain bones muscles right answer feedback:
brain right answer feedback:The ectoderm develops into many neural structures, including the central nervous system, as well as several integumentary structures.
The function of the ductus arteriosus is to __________. deliver oxygen-rich blood to the placenta bypass the coronary circuit deliver oxygen-poor blood to the placenta deliver oxygen-rich blood to the liver bypass the pulmonary circuit
bypass the pulmonary circuit right answer feedback:The function of the ductus arteriosus is to bypass the pulmonary circuit in order to help prevent congestion in the developing lungs.
The development of the primary germ layers is called __________. gastrulation organogenesis blastulation placentation cleavage
gastrulation right answer feedback:The development of the primary germ layers is called gastrulation. The three layers that form are the ectoderm, endoderm, and mesoderm.
Which hormone is required to maintain the corpus luteum and prevent menstruation? -estrogen -progesterone -human placental lactogen -hCG
hCG Correct Human chorionic gonadotropin (hCG) secreted by the placenta is required to maintain the corpus luteum and prevent menstruation.
During prophase I of meiosis, -chromosome pairs are positioned in the middle of the cell. -there are two daughter cells, each with 23 chromosomes. -there are four haploid daughter cells. -the homologous chromosomes separate and move towards opposite poles. -homologous chromosomes stick together in pairs. Submit
homologous chromosomes stick together in pairs. Correct Homologous chromosomes stick together in pairs during prophase I.
A cell preparing to undergo meiosis duplicates its chromosomes during -meiosis II -prophase I -interphase -metaphase I -anaphase I
interphase Correct Chromosomes are duplicated during interphase.
In males, which of the following includes the correct atrget and result of LH stimulation -sustentocytes: increased testosterone -sustentocytes: increased spermatogenesis -interstitial cells: increased androgen-binding protein (ABP) secretions -interstitial cells: increased androgen secretions
interstitial cells: increased androgen secretions Correct In males, LH targets interstitial cells. As a result of LH stimulation of interstitial cells, the levels of androgens, such as testosterone, increase.
Sperm are known to bear __________ that respond to chemical stimuli that help them locate the oocyte. tails hydrolytic enzymes olfactory receptors acrosomes
olfactory receptors Sperm are known to bear olfactory receptors that respond to chemical stimuli that help them locate the oocyte. The sperm has a tail that allows it to be motile, but it does not play a role in helping it locate the oocyte. The hydrolytic enzymes help the sperm penetrate the layers around the oocyte during fertilization, but they do not play a role in locating the oocyte. Acrosomes contain hydrolytic enzymes that help the sperm penetrate the membrane around the secondary oocyte, but they do not play a role in locating the oocyte.
If a male undergoes a vasectomy, which of the following can no longer take place? -passage of sperm cells from the rete testes to the epididymis duct -passage of sperm cells from the seminiferous tubules to the rete testes -passage of sperm cells from the epididymis duct to the epididymis tail -passage of sperm cells from the epididymis to the urethra
passage of sperm cells from the epididymis to the urethra Correct Since the ductus (vas) deferens is severed during a vasectomy, sperm cells can no longer pass from the epididymis to the penis.
The correct order of events during meiosis is -metaphase I, prophase I, telophase I, anaphase I, cytokinesis, meiosis II. -prophase I, anaphase I, metaphase I, telophase I, meiosis II, cytokinesis. -prophase I, anaphase I, telophase I, metaphase I, meiosis II. -prophase I, metaphase I, anaphase I, telophase I, cytokinesis, meiosis II. -metaphase I, prophase I, anaphase I, telophase I, cytokinesis, meiosis II.
prophase I, metaphase I, anaphase I, telophase I, cytokinesis, meiosis II. Correct Meiosis starts with prophase I and continues with metaphase I, anaphase I, telophase I, and cytokinesis. This is followed by meiosis II.
Which hormone produced by the placenta causes the mother's pubic symphysis to loosen and widen? estrogen progesterone hCG FSH relaxin
relaxin right answer feedback:Relaxin relaxes pelvic ligaments and joints. This increased flexibility eases birth passage.
What is the testicular target for follicle-stimulating hormone (FSH) -sustentocytes (Sertoli cells) -spermatozoa -interstitial endocrine cells (Leydig cells) -spermatogonia
sustentocytes (Sertoli cells) Correct Sustentocytes in the walls of the seminiferous tubules respond to FSH by releasing androgen-binding protein, which maintains high testosterone levels near developing sperm cells.
What is the function of the blood testis barrier? -to prevent activation of the immune system of the male against the developing sperm -to provide only select nutrients to the developing sperm -to ensure that semen contains only sperm and seminal fluid -to filter out male sex hormones Submit
to prevent activation of the immune system of the male against the developing sperm Correct: A male's immune system would identify sperm as foreign bodies. The blood testis barrier formed by sustentocytes in seminiferous tubules prevents that interaction.
What is the function of meiosis? to produce four cells, each with identical chromosomes to produce cells with double the chromosome number of the original cell to produce cells with half the chromosome number of the original spermatogonium or oogonium to produce genetically identical cells through the two nuclear divisions
to produce cells with half the chromosome number of the original spermatogonium or oogonium Correct Sperm and egg cells have half the chromosome number of the spermatogonium or oogonium. This is necessary so that they can combine to form a 2n zygote.
The only 100% effective method of birth control is __________. total abstinence Depo-Provera vasectomy MAPs right answer feedback:
total abstinence Total abstinence is the only 100% effective method of birth control.
Which of the following is NOT a function of the placenta? respiratory gas transfer nutrient transfer urine formation waste elimination hormone production
urine formation right answer feedback:Urine formation is not a function of the placenta.
Which of the following is NOT a change in female anatomy or physiology during pregnancy? -A tightening of pelvic ligaments to help bear the extra weight of the growing fetus -An increase in blood volume by as much as 40% -Nasal stuffiness and difficulty breathing -Increased urine output because of increased metabolic wastes generated by the mother and fetus
-A tightening of pelvic ligaments to help bear the extra weight of the growing fetus Correct The hormone relaxin relaxes pelvic ligaments and the pubic symphysis, allowing the pelvis to widen in preparation for birth.
Focus your attention on part (2) of Focus Figure 28.1. Which of the following statements about the acrosomal reaction is correct? -The acrosomal reactions of many sperm expose the sperm membrane. -The acrosomal enzymes released from many sperm digest holes through the zona pellucida. -Binding of sperm to the sperm-binding receptors in the corona radiata causes the Ca2+ levels within the sperm to increase. -The decrease of Ca2+Ca2+ levels
-The acrosomal enzymes released from many sperm digest holes through the zona pellucida. Correct After penetrating the corona radiata, sperm bind to ZP3 (zona protein 3) glycoprotein receptors found within the zona pellucida to trigger the acrosomal reaction. The acrosomal reaction involves release of acrosomal enzymes from the sperm to digest holes in the zona pellucida. Hundreds of sperm must release acrosomal enzymes that digest the zona pellucida and clear a path that enables the fertilizing sperm to reach the oocyte plasma membrane receptors.
Focus your attention on parts (3) and (4) of Focus Figure 28.1. Which statement best describes the result of binding and fusion of the sperm's membrane to the oocyte plasma membrane? =They cause an increase in Ca2+levels within the sperm. -They block multiple sperm from entering the oocyte. =They make the sperm's membrane more fragile. -They allow the contents of the sperm to enter the oocyte cytoplasm.
-They allow the contents of the sperm to enter the oocyte cytoplasm. Correct The sperm's membrane binds to the oocyte's sperm-binding receptors. This binding causes the sperm and oocyte plasma membranes to fuse together, allowing the contents of the sperm to enter the oocyte cytoplasm.
The small blue circles in the figure just inside the oocyte membrane represent vesicles containing calcium ions that are spilled into the extracellular space to prevent polyspermy. When does this take place? -just after the sperm head penetrates the corona radiata -just after the sperm head enters the intermembrane space -just after the sperm head penetrates the zona pellucida -just after the sperm's head enters the oocyte membrane
-just after the sperm's head enters the oocyte membrane Correct The release of calcium into the extracellular space occurs just after the sperm head enters the oocyte. The calcium effectively blocks sperm receptors in the zona pellucida.
Meconium is __________. -the hormone that causes a positive feedback mechanism to continue milk production -sloughed-off epithelial cells, bile, and other substances -the hormone that is termed "the natural birth control" and inhibits the release of GnRH -a fluid initially secreted by the mammary glands before true milk is produced
-sloughed-off epithelial cells, bile, and other substances right answer feedback:Meconium is a tarry green-black paste containing sloughed-off epithelial cells, bile, and other substances.
Focus your attention on part (5) of Focus Figure 28.1. Drag and drop the terms to the appropriate blanks in the sentences. Terms may be used once, more than once, or not at all.
1. Entry of the sperm's contents causes Ca2+Ca2+ levels Entry of the sperm's contents causes C a 2 + levels in the oocyte's cytoplasm to rise, triggering the cortical reaction. in the oocyte's cytoplasm to rise, triggering the cortical reaction. 2. The cortical reaction The cortical reaction involves the exocytosis of cortical granules near the oocyte plasma membrane. involves the exocytosis of cortical granules near the oocyte plasma membrane. 3. Polyspermy occurs when multiple Polyspermy occurs when multiple sperm enter the oocyte. Monospermy occurs when a single sperm enters the oocyte. sperm enter the oocyte. Monospermy occurs when a single sperm enters the oocyte. 4. In humans, after a single sperm enters the cytoplasm In humans, after a single sperm enters the cytoplasm, further sperm entry is prevented. , further sperm entry is prevented. 5. Zonal inhibiting proteins (ZIPs), enzymes from the cortical granules, cause the zona pellucida Zonal inhibiting proteins (ZIPs), enzymes from the cortical granules, cause the zona pellucida to harden and the zona pellucida to be clipped off. to harden and the sperm receptors Zonal inhibiting proteins (ZIPs), enzymes from the cortical granules, cause the zona pellucida to harden and the zona pellucida to be clipped off. to be clipped off. 6. The block of polyspermy The block of polyspermy occurs as a result of the cortical reaction, by detaching any sperm bound to the receptors and preventing additional sperm from entering. occurs as a result of the cortical reaction, by detaching any sperm bound to the receptors and preventing additional sperm from entering.
Focus your attention on part (1) of Focus Figure 28.1. Drag and drop the terms to the appropriate blanks in the sentences. Terms may be used once, more than once, or not at all.
1. Sperm freshly deposited in the vagina are incapable of penetrating an oocyte. 2. As sperm travel through the female reproductive tract, secretions of the cervix, uterus and uterine tubes capacitate the sperm by making their membranes more fragile and capable of releasing enzymes. 3. When capacitated sperm approach a secondary oocyte, they are able to weave past granulosa cells of the corona radiata with the aid of hyaluronidase enzymes present on their surface.
The number of chromosomes in a human gamete is __________; this is referred to as a __________ chromosome number. -23;haploid -23; diploid -46; haploid -46; haploid
23; haploid
Implantation of the blastocyst begins __________ after ovulation. 1 day 3 days 6 to 7 days 3 weeks 1 month
6 to 7 days right answer feedback:It takes about 3 to 4 days after fertilization for the egg to travel to the uterus, where it floats for 2 to 3 days before it begins implantation.
The Apgar score range that indicates a healthy baby is __________. 0 to 2 2 to 4 4 to 6 6 to 8 8 to 10
8 to 10 right answer feedback:An Apgar score of 8 to 10 indicates a healthy baby. Lower scores indicate one or more physiological problems.
During the preschool examination of a 4-year-old boy, you are unable to palpate his testes within the scrotal sac. His parents state that previous exams have been normal, and that the testes are clearly visible during baths. What is the most likely explanation? -A chilly examination room or your cold hands have activated the cremasteric reflex. -The testes may have migrated back up into the boy's abdomen since the last examination. -Because he does not trust you, the boy is deliberately causing his testes to retract close to his body. -The parents' observations are probably incorrect.
A chilly examination room or your cold hands have activated the cremasteric reflex. Correct The cremaster muscles elevate the testes, pulling them higher in the scrotum in response to cold temperatures.
Drag and drop the labels into the appropriate blanks in the sentences. Each term will be used once.
After birth, the ductus arteriosus becomes the ligamentum arteriosum. In the newborn, the foramen ovale transitions to a wall-like depression called the fossa ovalis. After birth, the umbilical vein will become the ligamentum teres. The fetal ductus venosus will form the ligamentum venosum in the newborn. The umbilical arteries in the fetus become the median umbilical ligaments in the newborn. Correct The various adaptations in the fetus transition to specific structures in the newborn; several of these adaptations are ligamentous structures, including the ligamentum teres, median umbilical ligaments, ligamentum arteriosus, and the ligamentum venosus. The fetal foramen ovale will become the fossa ovalis in the newborn
Which statement about maternal hormones during pregnancy is accurate? Estrogen levels increase throughout gestation. hCG levels remain stable throughout gestation. hCG levels increase throughout gestation. Progesterone levels decline throughout gestation. Estrogen levels decline throughout gestation.
Estrogen levels increase throughout gestation. right answer feedback:Estrogen and progesterone levels increase throughout pregnancy.
Coitus interruptus is among the most effective birth control methods. True False
False Coitus interruptus, or withdrawal of the penis just before ejaculation, is unreliable because control of ejaculation is never ensured. Additionally, sperm may be present in the pre-ejaculatory fluid secreted by the bulbourethral glands.
The ectoderm is the primary germ layer from which the digestive, respiratory, and urogenital systems and the associated glands form. True False
False Ectoderm fashions the structures of the nervous system and the skin epidermis.
The first major event in organogenesis is gastrulation. True False
False Gastrulation lays down the basic structural framework of the embryo and sets the stage for the rearrangements that occur during organogenesis. The first major event in organogenesis is neurulation.
__________ refers to events that occur from the time of fertilization (conception) until the infant is born. Gestation period Conceptus Embryo Pregnancy
Pregnancy Pregnancy refers to the events that occur from the time of fertilization (conception) until the infant is born. Gestation period extends by convention from the last menstrual period until birth.
Which of the following occurs 17-20 weeks into pregnancy, during the fetal period? Quickening occurs. The head of the fetus is nearly as large as the body. Sex is readily detected by observing the genitals. The eyes open.
Quickening occurs. At 17-20 weeks (month 5) quickening occurs (the mother feels spontaneous muscular activity of the fetus).
Why are the male testes located in the scrotum, outside the abdominopelvic cavity? -The testes begin their development outside of the abdominopelvic region. -Spermatogenesis is temperature sensitive. -Their external location is necessary for penile development. -Their external location influences the development of male secondary sexual characteristics.
Spermatogenesis is temperature sensitive. Correct Spermatogenesis, the production and maturation of sperm, requires a temperature lower than core body temperature.
Which of the following differentiates the follicular and luteal phases of the ovarian cycle? -The luteal phase occurs directly before ovulation while estrogen levels are high, and the follicular phase occurs directly after ovulation when estrogen levels drop. -The follicular phase is the period during which the follicle secretes estrogen, and the luteal phase is when the follicle secretes luteinizing hormone. -The follicular phase occurs directly before ovulation, and the luteal phase occurs directly after ovulation. -The follicular phase ends with a peak in progesterone production that triggers ovulation and the start of the luteal phase.
The follicular phase occurs directly before ovulation, and the luteal phase occurs directly after ovulation. Correct The follicular phase is the period in which the dominant follicle prepares for ovulation and secretes large amounts of estrogen. The luteal phase occurs after ovulation as the corpus luteum secretes progesterone and some estrogen.
Which of the following occurs eight weeks into pregnancy? Sex is readily detected by observing the genitals. The eyes open. Quickening occurs. The head of the fetus is nearly as large as the body.
The head of the fetus is nearly as large as the body. At eight weeks (end of embryonic period) the head is nearly as large as the body, all major brain regions are present, and the first brain waves are generated in the brain stem. Question
Which of the following does NOT describe a function of trophoblast cells? They secrete hCG. They take part in placental formation. They display L-selectin molecules on their surface after blastocyst hatching. The inner layers of trophoblasts lose their plasma membranes and invade the endometrium.
The inner layers of trophoblasts lose their plasma membranes and invade the endometrium. right answer feedback:The outer layers of trophoblasts lose their plasma membranes and invade the endometrium.
What is the main difference between oogenesis and spermatogenesis in terms of meiosis? -Oogenesis produces three polar bodies, while spermatogenesis produces only one. -Oogenesis does not include a second meiotic division. -Oogenesis takes place in the uterus, while spermatogenesis takes place in gonadal tissue. -The number of functional gametes produced is different.
The number of functional gametes produced is different. Correct In spermatogenesis, four functional gametes are produced, while oogenesis produces only one functional gamete because of the loss of three polar bodies.
Why does only one egg, rather than four eggs, develop during oogenesis, given that spermatogenesis results in four sperm formed from one stem cell? -Once formed, spermatids, but not oocytes, undergo additional rounds of division by mitosis. -Only one egg can be fertilized at a time. -Unequal cytoplasmic division ensures that a fertilized egg has ample nutrients for its journey to the uterus. -The egg does not go through the meiotic division processes that the sperm undergo.
Unequal cytoplasmic division ensures that a fertilized egg has ample nutrients for its journey to the uterus. Correct The unequal cytoplasmic division that results in one egg and three polar bodies ensures that a fertilized egg has ample nutrients for its journey to the uterus. Lacking nutrient-containing cytoplasm, the polar bodies degenerate and die. This is very different than the result of sperm formation.
The outermost extraembryonic membrane is the __________. chorion placenta allantois amnion yolk sac
chorion right answer feedback:The outermost extraembryonic membrane is the chorion, which is part of the placenta.
Which of the following does NOT prevent polyspermy? the zona reaction a decrease in zonal inhibiting proteins the release of enzymes into the extracellular space beneath the zona pellucida the release of Ca2+ after the sperm has entered the ovum the cortical reaction
a decrease in zonal inhibiting proteins right answer feedback:There is an increase in zonal inhibiting proteins after the sperm enters the ovum, which destroy sperm receptors on the ovum, preventing polyspermy.
What is the name for the period of time that extends from the last menstrual period until birth, which is approximately 280 days? a gestation period an embryo pregnancy the conceptus
a gestation period Correct The gestation period is the 40 week period of time that includes oocyte maturation, ovulation, fertilization, and embryonic and fetal development.
Which of the following is NOT produced by meiosis? - a sperm cell -a liver cell -an egg, or ovum - all of the given choices are produced by meiosis
a liver cell Correct Liver cells are somatic cells, and they are all produced by mitosis, not by meiosis.
Which portion of the sperm contains the enzymes needed to penetrate the oocyte? -midpiece -acrosome -head -tail
acrosome Correct The acrosome contains the hydrolytic enzymes needed to digest the zona pellucida on the oocyte.
Which of the following might be reported by a man with benign prostatic hypertrophy (BPH)? -feeling of the bladder is full, even just after urinating -having to strain to urinate -pain after ejaculation or during urination -All of the above
all of the above Correct Use your textbook to review the anatomy of the prostate gland, bladder and urethra to understand how the function of these organs can be impacted by BPH.
In humans, the extraembryonic membrane that composes the structural base for the umbilical cord is the __________. yolk sac chorion allantois amnion
allantois In humans, the allantois is the structural base for the umbilical cord that links the embryo to the placenta.
Which of these is the innermost (closest) structure that completely surrounds the embryo? -placenta -amnion -yolk sac -chorion
amnion Correct The amniotic fluid, found in the amnion and intimate with the embryo, protects the embryo from physical trauma and maintains a constant homeostatic temperature.
The disc-shaped placenta is formed from the __________. yolk sac chronic villi and the decidua capsularis inner cell mass chronic villi and the decidua basalis
chronic villi and the decidua basalis The chronic villi and the decidua basalis form the placenta. The inner cell mass is not involved in the formation of the placenta. The chronic villi and the decidua basalis form the placenta. The decidua capsularis is not involved in the formation of the placenta. The chronic villi and the decidua basalis form the placenta. The yolk sac is not involved in the formation of the placenta. The chronic villi and the decidua basalis form the placenta.
After fertilization, the zygote goes through a rapid period of cell divisions called __________. blastulation implantation organogenesis cleavage teratogenesis
cleavage right answer feedback:After fertilization, the zygote goes through a rapid period of cell divisions called cleavage, resulting in the blastocyst, which has many smaller cells.
Which of the following is NOT a common metabolic/physiological change that occurs in pregnant women? increased urine production glucose sparing hypermetabolism increased respiratory rate decreased blood pressure
decreased blood pressure right answer feedback:Decreased blood pressure is atypical in pregnant women. Both heart rate and blood pressure increase during pregnancy.
Which sequence shows the correct order of the stages of labor? dilation, expulsion, placental expulsion, dilation, placental dilation, placental, expulsion placental, dilation, expulsion expulsion, placental, dilation
dilation, expulsion, placental right answer feedback:The stages of labor are dilation, expulsion, and placental. The dilation stage is the longest period, lasting up to 12 hours on average.
When does the total number of chromosomes get reduced from 46 pairs to 23 individual chromosomes? during mitosis during metaphase II during meiosis I during interphase
during meiosis I Correct Chromosome pairs are separated during anaphase I, and this first division is called the "reduction division."
An implantation that takes place in a site other than the uterus is called __________. amniotic ectopic metopic hyadatic phytid right answer feedback:
ectopic right answer feedback:Most ectopic pregnancies occur in the uterine tubes.
Which structure represents the remnants of the atrial fetal shunt? ligamentum teres ductus arteriosus fossa ovalis ligamentum venosum foramen ovale
fossa ovalis right answer feedback:The fossa ovalis represents the remnants of the atrial fetal shunt.
Meiosis starts with a single diploid cell and produces -eight haploid cells -two haploid cells -four diploid cells -two diploid cells -four haploid cells
four haploid cells Correct Meiosis produces four haploid cells.
Which of the following is a likely result of meiosis? -two eggs, each with 23 chromosomes -two eggs, each with 46 chromosomes -four sperm, each with 23 chromosomes -four sperm, each with 46 chromosomes
four sperm, each with 23 chromosomes Correct In males, meiosis produces four sperm, each with 23 chromosomes.
Which of the following factors is NOT considered to be a teratogen? alcohol iron nicotine sedatives anticoagulants
iron right answer feedback:Iron is not a teratogen. Teratogens are substances that can cause severe congenital abnormalities.
Which hormone is most responsible for triggering ovulation? -progesterone -estrogen -follicle-stimulating hormone (FSH) -luteinizing hormone (LH)
luteinizing hormone (LH) Correct Estrogen levels increase during the follicular phase, which triggers a surge of LH. This surge of LH triggers ovulation.
Which of these meiosis stages is functionally the most similar to mitosis? -meiosis I -meiosis II -meiosis I with II -neither meiosis I nor II
meiosis II Correct Meiosis II is fundamentally identical to mitosis. Prophase II, anaphase II, metaphase II, and telophase II have the same events as their corresponding stages in mitosis.
Prolactin causes __________. myometrial contractions and let-down reflex milk production by the breast tissue uterine contractions only increased hCG excretion during the first month of pregnancy
milk production by the breast tissue right answer feedback:Prolactin stimulates milk production.
All of the following structures are derived from mesoderm EXCEPT __________. the liver nails cardiac muscle smooth muscle bone
nails right answer feedback:Mesoderm specializes into numerous structures located throughout the body. Nails, hair and the epidermis, however, are derived from ectoderm.
The first major event of organogenesis is __________. mesenchyme production amnion formation sporulation neurulation
neurulation Neurulation is the first event of organogenesis. Sporulation does not take place in humans. Neurulation is the first event of organogenesis. Amnion formation is not the first event in organogenesis. Neurulation is the first event of organogenesis. The formation of mesenchyme is not the first event in organogenesis. Neurulation is the first event of organogenesis.
The umbilical vein carries blood that is rich in __________ from the placenta to the fetus. -metabolic wastes -carbon dioxide -oxygen -nitrogen
oxygen Correct The umbilical cord is comprised of the umbilical vein and two umbilical arteries. Lending to knowledge from the cardiovascular system and a comparison of veins and arteries: Arteries take blood away from the heart and veins return blood back to the heart. Here, the umbilical vessels are in relationship to the fetus; therefore, the umbilical vein transports oxygenated and nutrient-rich blood to the fetus, and the umbilical arteries carry deoxygenated, nutrient-poor blood from the fetus to the placenta.
Which maternally derived hormone induces and controls labor via a positive feedback mechanism? oxytocin progesterone estrogen hCG ADH right answer feedback:
oxytocin right answer feedback:Oxytocin induces and controls labor via a positive feedback mechanism. Oxytocin is produced in the mother's hypothalamus and is secreted by the posterior pituitary.
Which portion of the penis is removed during circumcision? -prepuce (foreskin) -bulb of the penis -glans penis -crus of the penis
prepuce (foreskin) Correct The prepuce, or foreskin, forms a covering of the glans penis and is removed during circumcision. This procedure may confer some health benefits, particularly in cases of chronic infection, and is also a common religious practice.
During early gastrulation, what structure(s) appear(s) on the dorsal aspect of the embryonic disc and establish(e)s the longitudinal axis of the embryo? coelom notochord primitive streak somites
primitive streak Gastrulation begins when a groove with raised edges called the primitive streak appears on the dorsal aspect of the embryonic disc and establishes the longitudinal axis of the embryo. Somites are derived from mesoderm and specialize into sclerotome, myotome, and dermatome. The notochord is a rod that provides axial support of the embryo and is derived from mesoderm. The coelom is ventral body cavity.
Genetic variation of individual chromosomes occurs during __________. -metaphase I -anaphase I -prophase I -prophase II
prophase I Correct During prophase I, genetic recombination can occur as arms of homologous chromosomes become spliced with one another.
Chromosomes can exchange genetic information during a process called "crossing over." This occurs when homologous chromosomes are lined up in pairs. When does this happen? -metaphase II -prophase I -anaphase I anaphase II
prophase I Correct During prophase I, homologous chromosomes align with each other and undergo crossing over.
During meiosis, segments of nonsister chromatids can trade places. This recombination of maternal and paternal genetic material is a key feature of meiosis. During what phase of meiosis does recombination occur? -prophase I -Metaphase I -anaphase I -telophase I -meiosis II
prophase I Correct Segments of nonsister chromatids trade places during prophase I, resulting in recombination.
At what point during meiosis do homologous chromosomes pair up? -metaphase I -anaphase I -prophase II -prophase I
prophase I Correct The key event in meiosis, the pairing of homologous chromosomes, happens in prophase I. This sets the stage for halving the amount of DNA during the first cellular division.
Although effective in treating erectile dysfunction, Viagra has the side effect of reducing systemic blood pressure by causing ______. -a reduction in cardiac output -a reduction in parasympathetic stimulation of penile arterioles -relaxation of muscle tissue in arteries -decreased blood flow to the ventricular walls
relaxation of muscle tissue in arteries Correct Smooth muscle relaxation would lead to vasodilatation of arteries. Remember that blood pressure is directly affected by blood vessel diameter.
Which of the following structures produces the greatest amount of the secretions found in semen? -prostate -seminal glands -bulbo-urethral glands -epididymis
seminal glands Correct The secretions of the seminal glands account for some 70% of semen volume and function to increase sperm motility and fertilizing ability.
Which of the following shows the correct pathway for sperm cells as they leave the testes? -seminiferous tubule, rete testis, epididymis, ductus deferens -ductus deferens, epididymis, rete testis, seminiferous tubule, -ductus deferens, epididymis, seminiferous tubule, rete testis -rete testis, seminiferous tubule, epididymis, ductus deferens
seminiferous tubule, rete testis, epididymis, ductus deferens Correct This is the correct pathway. Sperm are stored in the tail of the epididymis until they are ejaculated. If they are not ejaculated, they will eventually break down and be phagocytized.
Sperm is produced in the __________. -ejaculatory duct -epididymis -ductus deferens -seminiferous tubules
seminiferous tubules Correct Sperm are made in the seminiferous tubules. Rather, fluid flow in the seminiferous tubules carries sperm as they are made toward an exit point from the testis.
The process of implantation generally begins __________ and is usually completed by __________. the day before ovulation; the third day after ovulation the day after ovulation; the third day after ovulation six to seven days after ovulation; the twelfth day after ovulation two to three days after ovulation; the sixth or seventh day after ovulation
six to seven days after ovulation; the twelfth day after ovulation Six to seven days after ovulation, given a properly prepared endometrium, implantation begins. Implantation, when successful, takes about five days; it is usually completed by the twelfth day after ovulation.
Which layer of the uterus is the site for implantation of a fertilized egg? -stratum functionalis of the endometrium -myometrium -stratum basalis of the endometrium -perimetrium
stratum functionalis of the endometrium Correct Implantation occurs at the stratum functionalis, the innermost layer of the uterus.
For successful fertilization to occur, coitus must occur NO more than __________ and NO later than __________. 24 hours before ovulation; two days after two days before ovulation; 24 hours after three days before ovulation; two days after two days before ovulation; two days after
two days before ovulation; 24 hours after The oocyte is viable for 12 to 24 hours after it is cast out of the ovary. The chance of pregnancy drops to almost zero the next day. Most sperm retain their fertilizing power for 24 to 48 hours after ejaculation. Consequently, for successful fertilization to occur, coitus must occur no more than two days before ovulation and no later than 24 hours after.
What part of the female system is the usual site of fertilization of the ovulated oocyte? -cervical canal -uterine (fallopian tube) -vagina -uterus
uterine (fallopian) tube Correct Eggs that successfully implant in the uterus are first fertilized in the uterine tube. This does not imply a "tubal pregnancy," where the zygote implants in the uterine tube.
Which of the following is an incorrect matching of female reproductive structures with their functions? -vagina; birth control -ovarian follicle: ovum (egg) production -uterus: fertilization of ovum by sperm -uterine tube; transport ovum to uterus
uterus: fertilization of ovum by sperm Correct The uterine tube is the location where fertilization generally occurs. The uterus (womb) is the organ that receives, retains, and nourishes the fertilized ovum during pregnancy.
With respect to their role in fetal circulation, the ductus venosus, foramen ovale, and ductus arteriosus are examples of a(n) _________________. -vascular shunt -hilum -anastomosis -vascular plexus
vascular shunt Correct The concept of a vascular shunt is one that routes materials from one point to another, bypassing a particular area. In this case, the ductus venosus, foramen ovale, and ductus arteriosus function to bypass blood from the developing fetal liver and lungs.
