1.
The dartos and cremaster muscles are important to the integrity of the male reproductive system. Which of the following is true about the role they play?
Correct Answer
D. They regulate the temperature of the testes
Explanation
The dartos and cremaster muscles are responsible for regulating the temperature of the testes. These muscles are located in the scrotum and help to control the position and tension of the testes. When it is cold, these muscles contract, bringing the testes closer to the body to keep them warm. Conversely, when it is warm, these muscles relax, allowing the testes to hang further away from the body to cool down. This temperature regulation is crucial for maintaining the proper environment for sperm production and overall reproductive function.
2.
The ability of sperm cells to move along the ductus deferens is due to ________________________.
Correct Answer
C. Peristaltic contractions
Explanation
Peristaltic contractions refer to the rhythmic muscular contractions that occur in the walls of the ductus deferens. These contractions help propel the sperm cells forward, allowing them to move along the ductus deferens. Therefore, the ability of sperm cells to move along the ductus deferens is due to peristaltic contractions.
3.
The ability of a male to ejaculate is due to the action of __________________.
Correct Answer
C. The bulbospongiosus muscles
Explanation
The bulbospongiosus muscles are responsible for the ability of a male to ejaculate. These muscles are located in the pelvic region and play a crucial role in the ejaculation process. When these muscles contract, they help propel semen out of the penis during ejaculation. Therefore, the action of the bulbospongiosus muscles is essential for the male reproductive system to function properly and for ejaculation to occur.
4.
The most important risk for testicular cancer in young males is ______________________.
Correct Answer
A. Non descent of the testes
Explanation
The most important risk for testicular cancer in young males is non descent of the testes. This refers to the condition where one or both testicles do not move down into the scrotum before birth. This condition increases the risk of testicular cancer because the undescended testicle(s) may be more prone to developing abnormal cells. It is important for parents and healthcare providers to monitor and address this condition early on to reduce the risk of testicular cancer in young males.
5.
Which of the following glands are responsible for 60% of the synthesis of semen?
Correct Answer
D. The seminal vesicles
Explanation
The seminal vesicles are responsible for 60% of the synthesis of semen. Seminal vesicles produce a fluid that makes up a significant portion of semen. This fluid contains various substances, including fructose, prostaglandins, and enzymes, which provide nourishment and energy for sperm. Therefore, the seminal vesicles play a crucial role in semen production and contribute to its overall composition.
6.
Which of the following hormones controls the release of anterior pituitary gonadotropins?
Correct Answer
A. GnRH
Explanation
GnRH (gonadotropin-releasing hormone) is responsible for controlling the release of anterior pituitary gonadotropins. It stimulates the release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from the anterior pituitary gland. These hormones play a crucial role in regulating reproductive functions such as the development of ovarian follicles and the production of testosterone. Testosterone, on the other hand, is not involved in controlling the release of anterior pituitary gonadotropins.
7.
Development of male reproductive structures depends on which of the following events?
Correct Answer
C. Secretion of male hormones prenatally and lasting into the first few months after birth
Explanation
The development of male reproductive structures depends on the secretion of male hormones prenatally and lasting into the first few months after birth. These hormones, such as testosterone, are responsible for the differentiation and growth of the male reproductive organs, including the testes, penis, and prostate gland. Without the proper secretion of these hormones during critical periods of development, the male reproductive structures may not develop properly, leading to various abnormalities or disorders.
8.
The primary function of the uterus is to ____________________________.
Correct Answer
D. Receive, retain, and nourish a fertilized ovum
Explanation
The primary function of the uterus is to receive, retain, and nourish a fertilized ovum. After fertilization, the fertilized egg implants itself into the lining of the uterus, where it is protected and provided with nutrients for development. This process is essential for pregnancy and the continuation of the species. The uterus plays a crucial role in supporting the growth of the fetus until birth.
9.
Why is the blood-testis barrier important?
Correct Answer
B. Because spermatozoa and developing cells produce surface antigens that are recognized as foreign by the immune system
Explanation
The blood-testis barrier is important because spermatozoa and developing cells produce surface antigens that are recognized as foreign by the immune system. Without this barrier, the immune system would attack and destroy the sperm cells, leading to infertility. The barrier prevents the entry of immune cells and antibodies into the testes, allowing for the development and maturation of sperm cells without interference from the immune system.
10.
The structures that receive the ovulated oocyte, providing a site for fertilization, are called the ________________________________
Correct Answer
A. Fallopian tubes
Explanation
The structures that receive the ovulated oocyte, providing a site for fertilization, are called the fallopian tubes. These tubes serve as a pathway for the oocyte to travel from the ovary to the uterus. It is in the fallopian tubes where fertilization typically occurs, as the sperm can meet and fertilize the oocyte in this location.
11.
If gametes were diploid like somatic cells, how many chromosomes would the zygote contain?
Correct Answer
B. Twice the diploid number, and with every succeeding generation, the chromosome number would continue to double and normal development could not occur
Explanation
If gametes were diploid like somatic cells, the zygote would contain twice the diploid number of chromosomes. This means that the chromosome number would double in each generation, leading to an abnormal increase in chromosome number. This abnormal chromosome number would prevent normal development from occurring.
12.
Human egg and sperm are similar in that ________________________.
Correct Answer
B. They have the same number of chromosomes
Explanation
The correct answer is that human eggs and sperm have the same number of chromosomes. This is because during fertilization, the egg and sperm combine to form a zygote, which contains the full set of chromosomes necessary for the development of a human being. Each egg and sperm cell contains 23 chromosomes, and when they combine, the resulting zygote will have a total of 46 chromosomes.
13.
The constancy of the chromosome number from one cell generation to the next is maintained through ____________________.
Correct Answer
D. Meiosis
Explanation
The correct answer is meiosis. Meiosis is a type of cell division that occurs in sexually reproducing organisms. It involves two rounds of division, resulting in the production of four genetically unique daughter cells. During meiosis, the chromosomes are replicated once, followed by two rounds of division, resulting in the halving of the chromosome number. This ensures that the chromosome number remains constant from one cell generation to the next in sexually reproducing organisms. Cytokinesis is the process of cell division where the cytoplasm divides, DNA synthesis is the replication of DNA, and mitosis is a type of cell division that produces two genetically identical daughter cells.
14.
Fertilization generally occurs in the _________________.
Correct Answer
D. Fallopian tubes
Explanation
Fertilization generally occurs in the fallopian tubes. This is where the sperm and egg meet and the fertilized egg implants itself in the uterus for further development. The fallopian tubes provide the necessary environment for successful fertilization to take place by allowing the sperm to travel towards the egg and providing a suitable site for the egg to be fertilized. The uterus, vagina, and ovary do not typically serve as the site for fertilization, making the fallopian tubes the correct answer.
15.
Spermiogenesis involves the __________________________________.
Correct Answer
C. Formation of a functional sperm by the stripping away of superfluous cytoplasm
Explanation
Spermiogenesis is the process by which spermatids, which are immature cells, undergo a series of changes to become mature, functional sperm. During this process, the excess cytoplasm is removed, leaving behind only the essential structures needed for fertilization. This stripping away of superfluous cytoplasm allows the sperm to become streamlined and more efficient in their movement. Therefore, the correct answer is "formation of a functional sperm by the stripping away of superfluous cytoplasm."
16.
All of the following can be considered male secondary sex characteristics except the ___________________________.
Correct Answer
B. Development of testes as opposed to ovaries
Explanation
The development of testes as opposed to ovaries is not considered a male secondary sex characteristic because it is a primary sex characteristic. Secondary sex characteristics are traits that develop during puberty and are not directly involved in reproduction, such as increasing mass of the skeleton, lowering of the voice, and development of body hair. Testes and ovaries are primary sex organs that determine an individual's biological sex.
17.
In humans, separation of the cells at the two-cel state following fertilization may lead to the production of twins, which in this case would be ____________________.
Correct Answer
A. Identical
Explanation
When cells separate at the two-cell stage following fertilization, it can lead to the production of identical twins. Identical twins occur when a single fertilized egg splits into two separate embryos, each with the same genetic makeup. This means that the twins will share the same sex and have very similar physical characteristics. Fraternal twins, on the other hand, occur when two separate eggs are fertilized by two different sperm, resulting in siblings with different genetic makeup and potentially different sexes. Therefore, the correct answer is "identical."
18.
Characteristics of the mature sperm include the _________________________________.
Correct Answer
D. Presence of Y chromosomes in approximately half the sperm
Explanation
The presence of Y chromosomes in approximately half the sperm is a characteristic of mature sperm. This is because sperm cells carry either an X or Y chromosome, which determines the sex of the offspring. If a sperm cell carries an X chromosome, it will result in a female offspring, while a sperm cell with a Y chromosome will result in a male offspring. Therefore, the presence of Y chromosomes in approximately half the sperm is a normal characteristic of mature sperm.
19.
How do the testes respond to exposure to excessive body warmth?
Correct Answer
D. They move away from the pelvic cavity
Explanation
Excessive body warmth can have a negative impact on the testes. In order to protect themselves from the high temperature, the testes move away from the pelvic cavity. This movement helps to maintain a cooler temperature for sperm production, as the testes need to be slightly cooler than the body's core temperature for optimal sperm production. This response is crucial for the overall health and functionality of the testes.
20.
Effects of estrogen include ________________________________.
Correct Answer
C. Growth of the breasts at puberty
Explanation
Estrogen is a hormone that plays a crucial role in the development of secondary sexual characteristics in females. During puberty, estrogen stimulates the growth of breast tissue, leading to the development of breasts. This is a normal part of female sexual development and is one of the primary effects of estrogen. The other options, such as increased oiliness of the skin, deepening of the voice, and growth of the larynx, are not directly associated with the effects of estrogen.
21.
Secretion of progesterone stimulates _________________________________.
Correct Answer
B. Preparation of the mammary glands for lactation
Explanation
Secretion of progesterone stimulates the preparation of the mammary glands for lactation. Progesterone is a hormone that is primarily involved in preparing the body for pregnancy and supporting the development of the uterus. One of its important functions is to prepare the mammary glands for breastfeeding. It promotes the growth and development of the glands, as well as the production of milk. This is essential for the nourishment of the baby after birth.
22.
Which of the following statements about sperm is not true?
Correct Answer
B. They are sluggish in an alkaline environment
Explanation
Sperm are not sluggish in an alkaline environment. In fact, they are adapted to survive and swim in the alkaline environment of the female reproductive tract. The alkaline environment helps to neutralize the acidity of the vaginal environment, allowing the sperm to reach the egg for fertilization.
23.
The cells that produce testosterone in the testis are called _________________.
Correct Answer
C. Interstitial cells
Explanation
The cells that produce testosterone in the testis are called interstitial cells. These cells are located in the spaces between the seminiferous tubules in the testis. They are responsible for the production and secretion of testosterone, which is the primary male sex hormone. Testosterone plays a crucial role in the development and maintenance of male reproductive tissues, as well as secondary sexual characteristics such as muscle mass, bone density, and facial hair growth.
24.
The testicular cells that construct the blood-testis barrier are the ____________________________.
Correct Answer
A. Sustentacular cells
Explanation
The sustentacular cells, also known as Sertoli cells, are responsible for constructing the blood-testis barrier. This barrier is essential for maintaining the unique microenvironment of the testes, protecting developing sperm cells from harmful substances, and allowing for proper sperm development. Sustentacular cells provide physical support, regulate the movement of substances between the blood and the seminiferous tubules, and also play a role in nourishing and nurturing developing sperm cells.
25.
Which of the following occurs as a result of undescended testes?
Correct Answer
A. Inadequate or nonviable sperm will be produced
Explanation
Undescended testes, also known as cryptorchidism, refers to a condition where one or both testes fail to descend into the scrotum. This can lead to inadequate or nonviable sperm production because the testes need to be in a cooler environment (scrotum) for proper sperm development. If the testes remain in the abdomen or inguinal canal, the higher temperature can impair sperm production. Therefore, the correct answer is that inadequate or nonviable sperm will be produced as a result of undescended testes.
26.
Erection of the penis results from _______________________.
Correct Answer
B. A parasympathetic reflex
Explanation
Erection of the penis results from a parasympathetic reflex. The parasympathetic nervous system is responsible for promoting relaxation and increased blood flow to the penis. When the parasympathetic nerves are activated, they cause the smooth muscles in the walls of the blood vessels in the penis to relax, allowing blood to flow into the erectile tissues and causing an erection. This reflex is triggered by sexual stimulation and is essential for the physiological process of achieving and maintaining an erection.
27.
Which is not a part of the proliferative phase of the female menstrual cycle?
Correct Answer
C. Corpus luteum
Explanation
The corpus luteum is not a part of the proliferative phase of the female menstrual cycle. The proliferative phase is characterized by the development of endometrial cells and the growth of vesicular follicles. During this phase, cervical mucus becomes thin and crystalline. The corpus luteum, on the other hand, is formed after ovulation and is responsible for the production of progesterone, which prepares the uterus for possible implantation of a fertilized egg.
28.
Which of the choices below is not a function of the vagina?
Correct Answer
C. Serves as a passageway from the primary oocyte
Explanation
The vagina does not serve as a passageway from the primary oocyte. The primary oocyte is released from the ovary during ovulation and travels through the fallopian tubes towards the uterus. The vagina is not directly involved in this process.
29.
Select the correct statement about male sexual response.
Correct Answer
C. Erection is the result of vascular spaces in the erectile tissues filling with blood
Explanation
Erection is the result of vascular spaces in the erectile tissues filling with blood. This means that during sexual arousal, the blood vessels in the erectile tissues of the penis dilate, allowing more blood to flow into these spaces. As a result, the penis becomes engorged and erect. This process is primarily regulated by the release of nitric oxide, which causes the smooth muscles in the blood vessel walls to relax and allow for increased blood flow.
30.
Which of the choices below is not a function of testosterone?
Correct Answer
D. Stimulates mammary gland development
Explanation
Testosterone is a hormone primarily responsible for the development and maintenance of male reproductive tissues and secondary sexual characteristics. It stimulates protein synthesis, which is essential for muscle growth and repair. It also stimulates the male pattern of development, including the growth of facial and body hair, deepening of the voice, and enlargement of the penis and testes. Additionally, testosterone contributes to male sexual behavior and spermatogenesis, the production of sperm. However, it does not stimulate mammary gland development, which is a function of other hormones like estrogen and prolactin.
31.
Which male hormone inhibits the secretion of FSH?
Correct Answer
C. Inhibin
Explanation
Inhibin is a hormone that is produced by the testes and acts to inhibit the secretion of follicle-stimulating hormone (FSH) from the pituitary gland. FSH is responsible for stimulating the production of sperm in males. Therefore, inhibin plays a crucial role in regulating the levels of FSH and ultimately the production of sperm. This makes inhibin the correct answer to the question.
32.
During the secretory phase of the menstrual cycle __________________.
Correct Answer
B. Progesterone levels are at their highest
Explanation
During the secretory phase of the menstrual cycle, progesterone levels are at their highest. This phase occurs after ovulation and is characterized by the thickening of the endometrium in preparation for possible implantation of a fertilized egg. Progesterone, which is primarily produced by the corpus luteum (the remnant of the ruptured follicle), helps to maintain the uterine lining and support a potential pregnancy. If fertilization does not occur, progesterone levels decrease, leading to the shedding of the endometrium during menstruation.
33.
Select the correct statement about the uterine cycle.
Correct Answer
D. If fertilization occurs, the corpus luteum is maintained by a hormone secreted by the developing embryo.
Explanation
During the uterine cycle, if fertilization occurs, the developing embryo secretes a hormone that maintains the corpus luteum. This is because the corpus luteum is responsible for producing progesterone, which is essential for maintaining the uterine lining and supporting pregnancy. The hormone secreted by the developing embryo ensures that the corpus luteum continues to produce progesterone, creating a suitable environment for implantation and pregnancy to continue.
34.
Which of the choices below is not a part of the brain-testicular axis?
Correct Answer
D. Thalamus
Explanation
The thalamus is not a part of the brain-testicular axis. The brain-testicular axis involves the hypothalamus, which releases gonadotropin-releasing hormone (GnRH) to stimulate the anterior pituitary gland. The anterior pituitary gland then releases luteinizing hormone (LH) and follicle-stimulating hormone (FSH), which act on the testes to regulate testosterone production and sperm production. The thalamus, on the other hand, is involved in relaying sensory information to the cerebral cortex and is not directly involved in the regulation of the testes.
35.
Which of the following statements is true concerning the mammary glands of both males and females?
Correct Answer
A. The mammary glands are modified sweat glands that are actually part of the integumentary system
Explanation
The mammary glands are modified sweat glands that are actually part of the integumentary system. This means that they are not specific to either males or females, as both sexes have mammary glands. They are responsible for producing and secreting milk during lactation. This statement is true because the mammary glands are indeed modified sweat glands and are considered part of the integumentary system, which includes the skin and its appendages.
36.
Normally menstruation occurs when __________________________
Correct Answer
D. Blood levels of estrogen and progesterone decrease
Explanation
Normally, menstruation occurs when blood levels of estrogen and progesterone decrease. These hormones are responsible for maintaining the lining of the uterus during the menstrual cycle. When their levels drop, it signals the body to shed the uterine lining, resulting in menstruation. This is a natural process that happens in the absence of fertilization and pregnancy.
37.
The basic difference between spermatogenesis and oogenesis is that ________________________.
Correct Answer
A. In oogenesis, one mature ovum is produced, and in spermatogenesis four mature sperm are produced from the parent cell
Explanation
The basic difference between spermatogenesis and oogenesis is that in oogenesis, one mature ovum is produced, and in spermatogenesis four mature sperm are produced from the parent cell. This is because during spermatogenesis, one diploid parent cell undergoes two rounds of meiosis to produce four haploid sperm cells. On the other hand, during oogenesis, one diploid parent cell undergoes one round of meiosis to produce one haploid ovum and two polar bodies, which eventually degenerate. Additionally, the mature ovum is haploid (n), while the sperm is diploid (2n).
38.
Occasionally three polar bodies are found clinging to the mature ovum. One came from an unequal division of the ovum, but from where did the other two arise?
Correct Answer
B. The first polar body has also divided to produce two polar bodies
Explanation
The correct answer states that the first polar body has also divided to produce two polar bodies. This means that one of the polar bodies formed from the unequal division of the ovum, while the other two polar bodies are produced from the division of the first polar body. This explanation provides a clear understanding of the origin of the three polar bodies found clinging to the mature ovum.
39.
Which of the following will occur after ovulation?
Correct Answer
C. The endometrium enters its secretory pHase
Explanation
After ovulation, the endometrium enters its secretory phase. This is because after the release of an egg from the ovary, the empty follicle that contained the egg (now called the corpus luteum) starts producing progesterone. Progesterone prepares the endometrium (the lining of the uterus) for implantation of a fertilized egg by thickening it and increasing its blood supply. This secretory phase occurs during the second half of the menstrual cycle and is an important step in the preparation of the uterus for potential pregnancy.
40.
Why doesn't semen enter the urinary bladder during ejaculation?
Correct Answer
D. The smooth muscle spHincter at the base of the urinary bladder closes
Explanation
During ejaculation, the smooth muscle sphincter at the base of the urinary bladder closes. This closure prevents semen from entering the urinary bladder and ensures that it is expelled through the urethra instead. This mechanism helps to separate the reproductive system from the urinary system and allows for the proper functioning of both systems without interference.
41.
Spermatogenesis ______________________________________
Correct Answer
C. Involves a kind of cell division limited to the gametes
Explanation
Spermatogenesis involves a kind of cell division limited to the gametes. This means that during spermatogenesis, only the cells that will become sperm undergo division, rather than all cells in the body. This process is essential for the production of mature sperm cells.
42.
Which hormone is absolutely necessary for ovulation to occur?
Correct Answer
B. LH
Explanation
LH (luteinizing hormone) is absolutely necessary for ovulation to occur. LH is produced by the pituitary gland and its surge triggers the release of a mature egg from the ovary. This surge usually occurs around the middle of the menstrual cycle, resulting in ovulation. Without the surge of LH, the egg would not be released, preventing ovulation from taking place.
43.
The brain-testicular axis __________________________________.
Correct Answer
C. Involves FSH and LH release
Explanation
The brain-testicular axis involves the release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH). FSH and LH are secreted by the anterior pituitary gland in response to gonadotropin-releasing hormone (GnRH) released by the hypothalamus. FSH stimulates the production of sperm cells in the testes, while LH stimulates the production of testosterone by the Leydig cells in the testes. This axis plays a crucial role in the regulation of testicular function and the maintenance of male reproductive health.
44.
Select the correct statement about testosterone control.
Correct Answer
B. GnRH from the hypothalamus causes FSH and LH release from the anterior pituitary
Explanation
GnRH from the hypothalamus causes FSH and LH release from the anterior pituitary. GnRH (gonadotropin-releasing hormone) is a hormone that is released by the hypothalamus and stimulates the release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from the anterior pituitary gland. FSH and LH then act on the testes to stimulate the production of testosterone. This is an important mechanism in the control of testosterone levels in the body.
45.
Which of the following is a correct statement about uterine tubes?
Correct Answer
A. The infundibulum is the funnel-shaped region near the ovary
Explanation
The infundibulum is the funnel-shaped region near the ovary. This is a correct statement about uterine tubes. The infundibulum is the outermost part of the uterine tube and has finger-like projections called fimbriae that help to capture the released egg from the ovary during ovulation. It acts as a funnel to guide the egg into the uterine tube for fertilization.
46.
Select the correct statement about the hormonal events of the ovarian cycle.
Correct Answer
A. High estrogen levels result in a surge of LH release
Explanation
High estrogen levels result in a surge of LH release. This is because as the follicles in the ovary mature, they produce increasing levels of estrogen. When estrogen levels reach a certain threshold, it triggers a positive feedback loop that leads to a surge in LH (luteinizing hormone) release from the pituitary gland. This LH surge then triggers ovulation, the release of the mature egg from the ovary. So, high estrogen levels are necessary for the LH surge to occur and for ovulation to take place.
47.
Which of these statements about sexually transmitted infections is false?
Correct Answer
D. SypHilis is caused by a virus that may lead to death if untreated
Explanation
Syphilis is not caused by a virus, but by a bacterium called Treponema pallidum. If left untreated, syphilis can indeed lead to serious complications and even death.
48.
Which of the following statements about spermatogenesis is not true?
Correct Answer
A. Each spermatid forms two sperm
Explanation
Each spermatid forms two sperm is not true. During spermatogenesis, each spermatid undergoes a process called spermiogenesis, where it matures and develops into a single sperm cell with a head, midpiece, and tail. Therefore, each spermatid forms only one sperm, not two.
49.
A boy who has not passed through puberty sustains an injury to his anterior pituitary such that FSH is no longer released, but LH is normal. After he grows to maturity, one would expect that he would __________________________
Correct Answer
C. Be sterile
Explanation
If the boy's anterior pituitary is injured and FSH is no longer released, it means that he will not be able to produce sperm. FSH is responsible for stimulating the production of sperm in the testes. Since LH is normal, it indicates that the boy's interstitial cells, which produce testosterone, are functioning properly. However, without FSH, the boy will not be able to produce mature sperm, leading to sterility. Therefore, the correct answer is that he would be sterile.
50.
Which of the following statements about the female reproductive process is not true?
Correct Answer
A. Rebuilding the endometrium is under the control of prolactin
Explanation
The statement "Rebuilding the endometrium is under the control of prolactin" is not true. Rebuilding the endometrium, which is the lining of the uterus, is actually under the control of estrogen and progesterone. Prolactin is a hormone that is primarily involved in milk production after childbirth.