Male Reproductive System and Hormones
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Questions and Answers

What hormone is produced primarily by Leydig cells in the testes?

  • Estradiol
  • Follicle-stimulating hormone
  • Luteinizing hormone
  • Testosterone (correct)

    • Which structure is NOT part of the male reproductive system?

  • Vas deferens
  • Epididymis
  • Ovary (correct)
  • Prostate

    • Which hormone can be converted peripherally to estradiol?

  • Testosterone (correct)
  • Luteinizing hormone
  • Inhibin B
  • Mullerian inhibiting substance

    • What is the function of inhibin B produced by Sertoli cells?

    <p>Inhibit follicle-stimulating hormone release</p> Signup and view all the answers

    What major change can occur in males when levels of estradiol increase?

    <p>Development of breasts</p> Signup and view all the answers

    Which of the following hormones is released from the anterior pituitary gland?

    <p>Follicle-stimulating hormone</p> Signup and view all the answers

    What identifies Leydig cells histologically in the testes?

    <p>Pink cytoplasm with Reinke crystals</p> Signup and view all the answers

    What role does the hypothalamic-pituitary-gonadal axis play?

    <p>Promotion of male sexual development and function</p> Signup and view all the answers

    Which hormone is primarily responsible for male development?

    <p>Testosterone</p> Signup and view all the answers

    What impact does estradiol have on the hypothalamus and anterior pituitary?

    <p>Suppresses hormone release</p> Signup and view all the answers

    What hormone released by the hypothalamus stimulates the anterior pituitary to produce ACTH?

    <p>Corticotropin-releasing hormone (CRH)</p> Signup and view all the answers

    Which part of the adrenal gland is responsible for producing weak androgens such as DHEA and androstenedione?

    <p>Zona reticularis</p> Signup and view all the answers

    What is the first stage of spermatogenesis?

    <p>Mitosis of spermatogonia</p> Signup and view all the answers

    What is the role of Sertoli cells in the male reproductive system?

    <p>Regulate spermatogenesis</p> Signup and view all the answers

    What is the primary function of Sertoli cells in the seminiferous tubules?

    <p>To form the blood-testis barrier</p> Signup and view all the answers

    What is typically a result of secondary hypogonadism?

    <p>Low spermatogenesis</p> Signup and view all the answers

    How long does it generally take for sperm to mature in the epididymis?

    <p>12 days</p> Signup and view all the answers

    What triggers the differentiation into the male phenotype during embryonic development?

    <p>Presence of the Y chromosome</p> Signup and view all the answers

    Which structure aids in lubricating the urethra before ejaculation?

    <p>Bulbourethral gland</p> Signup and view all the answers

    Which of the following is NOT a congenital cause of secondary hypogonadism?

    <p>Hyperprolactinemia</p> Signup and view all the answers

    Which hormone is responsible for the regression of Mullerian ducts during male fetal development?

    <p>Müllerian inhibiting substance (MIS)</p> Signup and view all the answers

    What is a normal range for total testosterone levels in adult males?

    <p>300 to 1000 ng/mL</p> Signup and view all the answers

    What effect can drugs like opiates have on testosterone levels?

    <p>Inhibit GnRH release</p> Signup and view all the answers

    What role does testosterone play during puberty in males?

    <p>Promotes deepening of the voice</p> Signup and view all the answers

    Which test is commonly used to screen for prostate cancer?

    <p>Blood prostate-specific antigen (PSA) test</p> Signup and view all the answers

    What occurs when there is insensitivity to androgens due to Androgen Insensitivity Syndrome?

    <p>Development of a female phenotype</p> Signup and view all the answers

    Which hormone stimulates Leydig cells to produce testosterone?

    <p>Luteinizing hormone (LH)</p> Signup and view all the answers

    What condition results from gonadal failure to produce adequate testosterone despite high LH and FSH levels?

    <p>Primary hypogonadism</p> Signup and view all the answers

    What is one result of low testosterone levels in men?

    <p>Failure to ejaculate</p> Signup and view all the answers

    What is the function of the seminal vesicles in the male reproductive system?

    <p>Produce fructose for sperm energy</p> Signup and view all the answers

    What is the primary androgen produced from cholesterol in the testes?

    <p>Testosterone</p> Signup and view all the answers

    Which condition is commonly associated with hyperprolactinemia?

    <p>Prolactinoma</p> Signup and view all the answers

    What triggers the release of GnRH from the hypothalamus during puberty?

    <p>Growth of the testes</p> Signup and view all the answers

    What can be a consequence of decreased testosterone levels in men?

    <p>Increased body fat</p> Signup and view all the answers

    What role do Sertoli cells play in spermatogenesis?

    <p>Support and nourish spermatogenic cells</p> Signup and view all the answers

    How do FSH and testosterone interact to promote spermatogenesis?

    <p>FSH and testosterone stimulate Sertoli cells to release androgen-binding protein</p> Signup and view all the answers

    Which of the following is NOT a role of dihydrotestosterone (DHT)?

    <p>Promoting breast development</p> Signup and view all the answers

    Which of the following is a potential effect of low testosterone levels on mental health?

    <p>Depressed mood</p> Signup and view all the answers

    What is a common acquired cause of secondary hypogonadism?

    <p>Trauma</p> Signup and view all the answers

    What happens to testosterone levels in men as they reach their 30s?

    <p>They begin to decline</p> Signup and view all the answers

    What is the role of dihydrotestosterone in male development?

    <p>Regulates male hair patterns and prostate function</p> Signup and view all the answers

    What key hormone is produced by Sertoli cells in the testes?

    <p>Inhibin B</p> Signup and view all the answers

    Which hormone indicates that the body is experiencing increased estradiol levels?

    <p>Follicle-stimulating hormone (FSH)</p> Signup and view all the answers

    What structure in the male reproductive system is responsible for sperm storage?

    <p>Epididymis</p> Signup and view all the answers

    How does testosterone exert its effects on target tissues?

    <p>By binding intracellular receptors</p> Signup and view all the answers

    What is the primary effect of increased estradiol levels on male physiology?

    <p>Weak bones and gynecomastia</p> Signup and view all the answers

    What structure is primarily involved in the production of testosterone?

    <p>Leydig cells</p> Signup and view all the answers

    What triggers the release of luteinizing hormone (LH) from the pituitary gland?

    <p>Gonadotropin-releasing hormone (GnRH)</p> Signup and view all the answers

    What is a consequence of testosterone being converted to estradiol in males?

    <p>Potential for infertility or libido loss</p> Signup and view all the answers

    Which structure promotes the formation and storage of sperm?

    <p>Testes</p> Signup and view all the answers

    What is the main function of Sertoli cells in the seminiferous tubules?

    <p>Formation of the blood-testis barrier</p> Signup and view all the answers

    Which hormone stimulates Leydig cells to produce testosterone?

    <p>LH</p> Signup and view all the answers

    Which of the following is a consequence of increased dihydrotestosterone (DHT) levels?

    <p>Male pattern baldness</p> Signup and view all the answers

    What is the role of testosterone during puberty in males?

    <p>Development of secondary sexual characteristics</p> Signup and view all the answers

    How is the release of GnRH from the hypothalamus characterized during puberty?

    <p>Pulsatile fashion every one to two hours</p> Signup and view all the answers

    Which enzyme is primarily responsible for converting testosterone to DHT?

    <p>5-alpha-reductase</p> Signup and view all the answers

    What is the effect of inhibin B produced by Sertoli cells?

    <p>Inhibits FSH release</p> Signup and view all the answers

    What essential role does testosterone play in male reproductive development?

    <p>Promotion of erythropoiesis</p> Signup and view all the answers

    What typically marks the beginning of puberty in males?

    <p>Growth of the testes</p> Signup and view all the answers

    What is the function of the sex-determining region (SRY) gene on the Y chromosome?

    <p>Induction of testosterone production</p> Signup and view all the answers

    What is the primary role of adrenocorticotropic hormone (ACTH) in the adrenal glands?

    <p>It stimulates the conversion of cholesterol into pregnenolone.</p> Signup and view all the answers

    Which components make up a mature sperm?

    <p>Head, midpiece, and tail.</p> Signup and view all the answers

    Which structure in the male reproductive system is responsible for sperm storage?

    <p>Epididymis.</p> Signup and view all the answers

    What blood test is commonly used to evaluate testosterone levels in men?

    <p>Blood testosterone level test.</p> Signup and view all the answers

    Which process initiates spermatogenesis in the testes?

    <p>Mitosis of diploid spermatogonia.</p> Signup and view all the answers

    What is the function of the seminal vesicles in the male reproductive system?

    <p>To provide energy for sperm motility.</p> Signup and view all the answers

    What condition results from the failure of the testes to produce adequate testosterone despite high LH and FSH levels?

    <p>Primary hypogonadism.</p> Signup and view all the answers

    What role does vasodilation play during sexual arousal?

    <p>It brings blood flow to the penis for erection.</p> Signup and view all the answers

    What is the likely consequence of hypogonadism in males?

    <p>Infertility or reduced reproductive function.</p> Signup and view all the answers

    What is typically examined in a semen analysis for evaluating male fertility?

    <p>Count, motility, and shape of sperm.</p> Signup and view all the answers

    What is the primary effect of testosterone on Leydig and Sertoli cells?

    <p>It enhances their ability to respond to stimuli.</p> Signup and view all the answers

    What physiological condition often results from hyperprolactinemia?

    <p>Suppressed GnRH release.</p> Signup and view all the answers

    Which of the following conditions is NOT a congenital cause of secondary hypogonadism?

    <p>Prolactinoma.</p> Signup and view all the answers

    Which symptom is commonly associated with low testosterone levels in men?

    <p>Decreased libido.</p> Signup and view all the answers

    What is one potential consequence of hypogonadism in males?

    <p>Loss of bone density.</p> Signup and view all the answers

    What type of mutation can lead to disruption in GnRH release?

    <p>Beta-subunit mutations in LH or FSH.</p> Signup and view all the answers

    What distinguishes androgen insensitivity syndrome from other forms of hypogonadism?

    <p>It leads to female phenotype despite male genotype.</p> Signup and view all the answers

    Which of the following best describes systemic diseases in relation to male reproductive health?

    <p>They may affect hormonal balance and reproductive function.</p> Signup and view all the answers

    What is a common effect of decreased testosterone on mental health?

    <p>Increased anxiety or depression.</p> Signup and view all the answers

    Which factor can influence spermatogenesis aside from testosterone levels?

    <p>High ambient temperature.</p> Signup and view all the answers

    What initiates the release of adrenocorticotropic hormone (ACTH) from the anterior pituitary?

    <p>Corticotropin-releasing hormone from the hypothalamus</p> Signup and view all the answers

    What are the weak androgens produced by the zona reticularis of the adrenal cortex?

    <p>DHEA and androstenedione</p> Signup and view all the answers

    Which structure plays a crucial role in the maturation of spermatozoa?

    <p>Epididymis</p> Signup and view all the answers

    What is a function of the seminal vesicles in the male reproductive system?

    <p>Producing fructose to nourish sperm</p> Signup and view all the answers

    What is the role of the prostate during ejaculation?

    <p>Thickening the semen with alkaline fluid</p> Signup and view all the answers

    What occurs during spermatogenesis after mitosis of primary spermatocytes?

    <p>Meiosis I produces haploid secondary spermatocytes</p> Signup and view all the answers

    What factor maintains male reproductive function during puberty?

    <p>Androgens such as testosterone</p> Signup and view all the answers

    What are common assays used to evaluate male reproductive function?

    <p>Blood testosterone levels and semen analysis</p> Signup and view all the answers

    Which of the following structures aid in delivering sperm during ejaculation?

    <p>Ductus deferens</p> Signup and view all the answers

    What is the typical testosterone level range in adult males?

    <p>300 to 1000 ng/mL</p> Signup and view all the answers

    Which hormone primarily modulates testosterone production in males?

    <p>Follicle-stimulating hormone (FSH)</p> Signup and view all the answers

    What is a potential consequence of high estradiol levels in males?

    <p>Gynecomastia</p> Signup and view all the answers

    Which structure in the male reproductive system is primarily responsible for sperm transportation?

    <p>Vas deferens</p> Signup and view all the answers

    Which cells produce inhibin B in the male reproductive system?

    <p>Sertoli cells</p> Signup and view all the answers

    What is the main role of Leydig cells in the testes?

    <p>Production of testosterone</p> Signup and view all the answers

    What structure is NOT considered an external part of the male reproductive system?

    <p>Vas deferens</p> Signup and view all the answers

    Which hormone is produced from cholesterol within the Leydig cells?

    <p>Testosterone</p> Signup and view all the answers

    What is the function of dihydrotestosterone (DHT) in males?

    <p>Development of male secondary sexual characteristics</p> Signup and view all the answers

    What is a primary function of the Sertoli cells in the testes?

    <p>Support and nourishment of developing sperm</p> Signup and view all the answers

    Which hormone produced by the anterior pituitary gland stimulates testosterone synthesis?

    <p>Luteinizing hormone (LH)</p> Signup and view all the answers

    What effect does hyperprolactinemia have on the reproductive system?

    <p>Suppresses GnRH release</p> Signup and view all the answers

    What is the consequence of a disruption in the hypothalamic-pituitary axis?

    <p>Decreased release of GnRH, LH, and FSH</p> Signup and view all the answers

    Which of the following conditions is primarily linked to androgen insensitivity syndrome?

    <p>Ineffective response to testosterone</p> Signup and view all the answers

    What is the primary result of underdeveloped Leydig or Sertoli cells in males?

    <p>Loss of proper reproductive function</p> Signup and view all the answers

    Which factor is NOT associated with low testosterone levels?

    <p>High exercise levels</p> Signup and view all the answers

    What role do Sertoli cells play in the male reproductive system?

    <p>Facilitate nutrient transfer to developing sperm</p> Signup and view all the answers

    What happens when the body experiences mutations related to GnRH release?

    <p>Congenital hormonal deficiencies</p> Signup and view all the answers

    What condition is associated with a loss of spermatogenesis due to a lack of stimuli to the testes?

    <p>Secondary hypogonadism</p> Signup and view all the answers

    Which of the following symptoms is NOT commonly associated with low testosterone levels?

    <p>Enhanced muscle growth</p> Signup and view all the answers

    What is a potential consequence of defects in androgen action in males?

    <p>Male infertility with normal testosterone levels</p> Signup and view all the answers

    What characterizes Sertoli cells in relation to germ cells?

    <p>They are larger than germ cells and have less prominent nuclei.</p> Signup and view all the answers

    What initiates the production of testosterone during puberty?

    <p>Increased levels of GnRH from the hypothalamus.</p> Signup and view all the answers

    What is the role of Dihydrotestosterone (DHT) in male development?

    <p>It promotes development of male external genitalia.</p> Signup and view all the answers

    What happens when testosterone levels increase during puberty?

    <p>Growth and pigmentation of the scrotum and penis.</p> Signup and view all the answers

    What is one consequence of excessive dihydrotestosterone (DHT) levels?

    <p>Increased risk of prostate development and male pattern balding.</p> Signup and view all the answers

    What is the relationship between GnRH and FSH or LH secretion?

    <p>GnRH stimulates FSH and LH release in a pulsatile manner.</p> Signup and view all the answers

    What effect does inhibin B have in the male reproductive system?

    <p>It serves as negative feedback to decrease FSH release.</p> Signup and view all the answers

    How does testosterone maintain hormonal balance in the male body?

    <p>By inhibiting the secretion of LH and FSH.</p> Signup and view all the answers

    What is the function of Leydig cells in the testes?

    <p>They secrete testosterone in response to LH.</p> Signup and view all the answers

    What triggers the descent of the testes during development?

    <p>Presence of the SRY gene on the Y chromosome.</p> Signup and view all the answers

    What do Sertoli cells primarily support during spermatogenesis?

    <p>Formation of the blood-testis barrier</p> Signup and view all the answers

    What signals the onset of puberty in males?

    <p>A sudden rise in GnRH</p> Signup and view all the answers

    How does dihydrotestosterone (DHT) primarily influence male physical characteristics?

    <p>Stimulates growth of the scrotum and penis</p> Signup and view all the answers

    What is the primary role of testosterone in male reproductive development?

    <p>Promoting the growth of Wolffian ducts</p> Signup and view all the answers

    Which hormone acts on Sertoli cells to promote sperm production?

    <p>Follicle-stimulating hormone (FSH)</p> Signup and view all the answers

    What is one of the main functions of inhibin B produced by Sertoli cells?

    <p>To provide negative feedback on FSH release</p> Signup and view all the answers

    What is a consequence of the decline in testosterone levels as men age?

    <p>Decreased bone density</p> Signup and view all the answers

    What characteristic is NOT associated with primary effects of testosterone during puberty?

    <p>Inhibition of Leydig cells</p> Signup and view all the answers

    What role does the hypothalamus play in regulating male reproductive function?

    <p>Releases GnRH in a pulsatile manner</p> Signup and view all the answers

    What structure in the male reproductive system is responsible for the production of sperm?

    <p>Seminiferous tubules</p> Signup and view all the answers

    What is the role of Leydig cells in the male reproductive system?

    <p>To produce testosterone</p> Signup and view all the answers

    What hormone is primarily associated with the regulation of sexual development and function in males?

    <p>Testosterone</p> Signup and view all the answers

    Which of the following hormones is produced by Sertoli cells?

    <p>Inhibin B</p> Signup and view all the answers

    How does dihydrotestosterone (DHT) contribute to male development?

    <p>Enhances secondary sexual characteristics</p> Signup and view all the answers

    What is a condition that can lead to secondary hypogonadism?

    <p>Hyperprolactinemia</p> Signup and view all the answers

    What is the effect of increased estradiol levels in males?

    <p>Gynecomastia</p> Signup and view all the answers

    What is the primary role of Sertoli cells in the male reproductive system?

    <p>Support and nourish spermatogenic cells</p> Signup and view all the answers

    What is the function of the hypothalamic-pituitary-gonadal axis?

    <p>To promote and maintain sexual development</p> Signup and view all the answers

    What is one consequence of low testosterone levels in men?

    <p>Decreased bone density</p> Signup and view all the answers

    Which of the following structures is responsible for sperm storage?

    <p>Epididymis</p> Signup and view all the answers

    How do defects in androgen action affect male phenotype development?

    <p>Lead to external male genitalia with internal female structures</p> Signup and view all the answers

    What regulates the release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH)?

    <p>Gonadotropin-releasing hormone (GnRH)</p> Signup and view all the answers

    What impact does testosterone exert on target tissues?

    <p>Enhancement of protein expression</p> Signup and view all the answers

    What is one acquired cause of secondary hypogonadism?

    <p>Trauma or irradiation</p> Signup and view all the answers

    What is one consequence of testosterone being converted to estradiol in males?

    <p>Development of gynecomastia</p> Signup and view all the answers

    What condition is caused by the inability of tissues to respond to testosterone despite its high levels?

    <p>Androgen insensitivity syndrome</p> Signup and view all the answers

    What are potential comorbidities associated with low testosterone levels in men?

    <p>Metabolic syndrome and atherosclerosis</p> Signup and view all the answers

    What stimulates the release of testosterone from Leydig cells?

    <p>Luteinizing hormone (LH)</p> Signup and view all the answers

    Which of the following is a symptom of low testosterone levels in men?

    <p>Loss of body hair</p> Signup and view all the answers

    What is the main role of the adrenal glands in the hypothalamic-pituitary-adrenal axis?

    <p>Converting cholesterol into pregnenolone</p> Signup and view all the answers

    What can reduce GnRH release and lead to low testosterone levels?

    <p>Hyperprolactinemia</p> Signup and view all the answers

    Which component of the sperm provides energy for motility?

    <p>Midpiece</p> Signup and view all the answers

    What initiates spermatogenesis at puberty?

    <p>Mitosis of diploid spermatogonia</p> Signup and view all the answers

    What is the function of the prostate gland in the male reproductive system?

    <p>Produce alkaline fluid to thicken semen</p> Signup and view all the answers

    What test is commonly used to establish fertility status in males?

    <p>Semen analysis</p> Signup and view all the answers

    What is typically the cause of primary hypogonadism?

    <p>Gonadal failure to produce adequate testosterone</p> Signup and view all the answers

    How long does sperm typically take to mature in the epididymis?

    <p>Twelve days</p> Signup and view all the answers

    What effect does vasodilation during sexual arousal have on the penis?

    <p>Leads to erection</p> Signup and view all the answers

    What component of the sperm consists of lysosomes aiding fertilization?

    <p>Head</p> Signup and view all the answers

    What is a major consequence of a deficiency in testosterone levels in males?

    <p>Impaired fertility</p> Signup and view all the answers

    What is the primary function of the Sertoli cells in the male reproductive system?

    <p>Promoting spermatogenesis</p> Signup and view all the answers

    Which hormone is primarily responsible for stimulating the growth and pigmentation of the scrotum and penis during puberty?

    <p>Testosterone</p> Signup and view all the answers

    What role does dihydrotestosterone (DHT) have in male development?

    <p>Stimulating development of prostate, scrotum, and penis</p> Signup and view all the answers

    What is the effect of GnRH release from the hypothalamus prior to puberty?

    <p>Stimulation of LH and FSH release</p> Signup and view all the answers

    How does testosterone affect the hypothalamic-pituitary-gonadal axis?

    <p>Inhibits secretion of LH and FSH</p> Signup and view all the answers

    What is the relationship between Sertoli cells and the blood-testis barrier?

    <p>Sertoli cells form the barrier through tight junctions</p> Signup and view all the answers

    What initiates the secretion of GnRH in males during puberty?

    <p>Sudden rise of GnRH from the hypothalamus</p> Signup and view all the answers

    What role does inhibin B play in the male reproductive system?

    <p>Providing negative feedback to decrease FSH release</p> Signup and view all the answers

    What is the primary hormone produced by Leydig cells in response to LH stimulation?

    <p>Testosterone</p> Signup and view all the answers

    How does testosterone affect muscle growth in males?

    <p>It increases muscle mass and strength</p> Signup and view all the answers

    What condition results from a disruption in the hypothalamic-pituitary axis leading to low testosterone production?

    <p>Secondary hypogonadism</p> Signup and view all the answers

    Which of the following is a potential acquired cause of secondary hypogonadism?

    <p>Prolactinoma</p> Signup and view all the answers

    What effect does hyperprolactinemia have on the reproductive system?

    <p>Suppression of GnRH release</p> Signup and view all the answers

    What can be a consequence of defective androgen action in males?

    <p>Incomplete sexual development</p> Signup and view all the answers

    What is a common clinical presentation of male reproductive disorders due to low testosterone?

    <p>Low libido</p> Signup and view all the answers

    What characterizes androgen insensitivity syndrome?

    <p>Female phenotype despite male genotype</p> Signup and view all the answers

    What additional health issue is often associated with low testosterone levels?

    <p>Metabolic syndrome</p> Signup and view all the answers

    What role do Sertoli cells play in spermatogenesis?

    <p>Support and nourish developing sperm</p> Signup and view all the answers

    Which patient symptom could indicate low testosterone levels in men?

    <p>Depressed mood</p> Signup and view all the answers

    What effect does a mutation in the kisspeptin/GPR54 system have on reproduction?

    <p>Disrupts GnRH release</p> Signup and view all the answers

    What initiates the production of adrenal hormones in the adrenal glands?

    <p>Corticotrophin-releasing hormone (CRH)</p> Signup and view all the answers

    How long does one cycle of spermatogenesis approximately take?

    <p>13 days</p> Signup and view all the answers

    Which structure is responsible for the maturation of spermatozoa?

    <p>Epididymis</p> Signup and view all the answers

    What is the primary function of the seminal vesicles?

    <p>Providing energy for sperm motility</p> Signup and view all the answers

    Which condition is a congenital cause of primary hypogonadism?

    <p>Klinefelter syndrome</p> Signup and view all the answers

    What component of the sperm contains mitochondria for energy production?

    <p>Midpiece</p> Signup and view all the answers

    Which test helps establish fertility status and evaluates sperm characteristics?

    <p>Semen analysis</p> Signup and view all the answers

    What hormone primarily regulates the function of Sertoli cells?

    <p>Follicle-stimulating hormone (FSH)</p> Signup and view all the answers

    What is the purpose of the alkaline fluid secreted by the prostate?

    <p>To neutralize acidity in the female reproductive tract</p> Signup and view all the answers

    What common test should begin around 50 years of age to screen for prostate cancer?

    <p>Blood prostate-specific antigen test (PSA)</p> Signup and view all the answers

    What is the function of the scrotum in the male reproductive system?

    <p>To regulate temperature for sperm production</p> Signup and view all the answers

    Which cells are responsible for producing inhibin B in the male reproductive system?

    <p>Sertoli cells</p> Signup and view all the answers

    What hormone primarily stimulates Leydig cells to produce testosterone?

    <p>Luteinizing hormone (LH)</p> Signup and view all the answers

    Which of the following describes the action of dihydrotestosterone (DHT) in males?

    <p>It plays a role in the development of male secondary sexual characteristics</p> Signup and view all the answers

    How does aromatase contribute to male hormone regulation?

    <p>It converts testosterone to estradiol</p> Signup and view all the answers

    What role does estradiol play when levels are elevated in males?

    <p>It can lead to gynecomastia</p> Signup and view all the answers

    What primarily regulates follicle-stimulating hormone (FSH) secretion?

    <p>Gonadotropin-releasing hormone (GnRH)</p> Signup and view all the answers

    What is the primary site of testosterone production?

    <p>Testes</p> Signup and view all the answers

    Which of the following hormones exert inhibitory effects on the hypothalamus and anterior pituitary?

    <p>Estradiol and testosterone</p> Signup and view all the answers

    What is a key characteristic of Leydig cells in histology?

    <p>Presence of pink cytoplasm and Reinke crystals</p> Signup and view all the answers

    Which condition can lead to low testosterone levels due to disruption in the hypothalamic-pituitary axis?

    <p>Kallmann's syndrome</p> Signup and view all the answers

    What is a common effect of hyperprolactinemia on GnRH release?

    <p>Suppresses GnRH release</p> Signup and view all the answers

    Which of the following disorders is characterized by an inability of the body's tissues to respond to testosterone?

    <p>Androgen insensitivity syndrome</p> Signup and view all the answers

    What impact does low testosterone generally have on mental health?

    <p>Decreased libido and energy</p> Signup and view all the answers

    What hormone is primarily responsible for stimulating testosterone production in Leydig cells?

    <p>LH</p> Signup and view all the answers

    Which factor can contribute to decreased spermatogenesis in men?

    <p>Increased estradiol</p> Signup and view all the answers

    Which of these is NOT a potential acquired cause of secondary hypogonadism?

    <p>Genetic mutation</p> Signup and view all the answers

    What condition might be characterized by incomplete sexual development if it occurs before puberty?

    <p>Secondary hypogonadism</p> Signup and view all the answers

    What is the primary role of Sertoli cells in the seminiferous tubules?

    <p>Support and nourish germ cells</p> Signup and view all the answers

    Which symptom is NOT typically associated with low testosterone levels?

    <p>Increased muscle mass</p> Signup and view all the answers

    What role does kisspeptin play in male reproductive function?

    <p>Regulates GnRH release</p> Signup and view all the answers

    Which hormone is produced by the Leydig cells in the testes?

    <p>Testosterone</p> Signup and view all the answers

    What initiates the growth and pigmentation of the scrotum and penis during puberty?

    <p>Rise in luteinizing hormone (LH)</p> Signup and view all the answers

    What happens during the interaction of FSH and testosterone in Sertoli cells?

    <p>They promote the release of androgen-binding protein</p> Signup and view all the answers

    What effect does dihydrotestosterone (DHT) have during male development?

    <p>Stimulates development of male external genitalia</p> Signup and view all the answers

    What does the regulation of GnRH, FSH, and LH levels from puberty represent?

    <p>Feedback loop for spermatogenesis</p> Signup and view all the answers

    Which structure forms the blood-testis barrier?

    <p>Sertoli cells</p> Signup and view all the answers

    What is the main function of inhibin B released from Sertoli cells?

    <p>Inhibit FSH release from the anterior pituitary</p> Signup and view all the answers

    How does testosterone exert its negative feedback effect?

    <p>Reduces the release of GnRH and LH</p> Signup and view all the answers

    During what age range does puberty typically begin in males?

    <p>11 to 13 years</p> Signup and view all the answers

    What is the primary function of the male reproductive system's external structures?

    <p>To facilitate ejaculation</p> Signup and view all the answers

    Which hormone is produced by Sertoli cells and has a role in the male reproductive system?

    <p>Inhibin B</p> Signup and view all the answers

    What is the role of dihydrotestosterone (DHT) in the male reproductive system?

    <p>Promoting tissue growth and differentiation</p> Signup and view all the answers

    In what manner do follicle-stimulating hormone (FSH) and luteinizing hormone (LH) interact?

    <p>LH stimulates Leydig cells to produce testosterone and FSH supports spermatogenesis</p> Signup and view all the answers

    What can result from excess levels of estradiol in males?

    <p>Development of gynecomastia</p> Signup and view all the answers

    Which key aspect of the hypothalamic-pituitary-gonadal axis is regulated by gonadotropin-releasing hormone (GnRH)?

    <p>Release of FSH and LH</p> Signup and view all the answers

    What is the primary role of the hypothalamic-pituitary-adrenal axis?

    <p>Controlling the adrenal glands' response to stress</p> Signup and view all the answers

    What is a significant characteristic of Leydig cells when observed histologically?

    <p>Pink cytoplasm with Reinke crystals</p> Signup and view all the answers

    How does testosterone primarily exert its effects in target tissues?

    <p>By binding to intracellular receptors</p> Signup and view all the answers

    How long does one full cycle of spermatogenesis take on average?

    <p>13 days</p> Signup and view all the answers

    What happens to sperm in the epididymis?

    <p>They mature and develop motility</p> Signup and view all the answers

    What systemic effect can increased estradiol levels have in males?

    <p>Decreased sperm motility</p> Signup and view all the answers

    What is the primary hormonal product of the male reproductive system that promotes sexual development?

    <p>Testosterone</p> Signup and view all the answers

    What is a common consequence of primary hypogonadism?

    <p>Inadequate production of testosterone</p> Signup and view all the answers

    What is contained within the acrosome of a mature sperm?

    <p>Lysosomes</p> Signup and view all the answers

    Which structure produces fructose that helps nourish sperm?

    <p>Seminal vesicles</p> Signup and view all the answers

    What is the function of the bulbourethral glands or Cowper's glands?

    <p>To lubricate the urethral opening</p> Signup and view all the answers

    Which of the following hormones is primarily responsible for stimulating the release of adrenal hormones?

    <p>Corticotropin-releasing hormone (CRH)</p> Signup and view all the answers

    What typically initiates sexual arousal in males?

    <p>Vasodilation of genital blood vessels</p> Signup and view all the answers

    Which blood test is commonly performed to assess male reproductive function?

    <p>Testosterone levels</p> Signup and view all the answers

    What results from a disruption in the hypothalamic-pituitary axis?

    <p>Secondary hypogonadism</p> Signup and view all the answers

    What is a common cause of hyperprolactinemia?

    <p>Prolactinomas</p> Signup and view all the answers

    Which condition can result from androgen insensitivity syndrome?

    <p>A female phenotype despite male genotype</p> Signup and view all the answers

    What role do Sertoli cells play in spermatogenesis?

    <p>They support and nourish developing sperm</p> Signup and view all the answers

    What can result from low testosterone levels in men?

    <p>Decreased bone density</p> Signup and view all the answers

    Which is an acquired cause of infertility in men?

    <p>Testicular trauma</p> Signup and view all the answers

    What is the impact of hyperprolactinemia on GnRH release?

    <p>It suppresses GnRH release</p> Signup and view all the answers

    What is the primary function of dehydroepiandrosterone (DHEA) in the male reproductive system?

    <p>To act as a precursor to other androgens</p> Signup and view all the answers

    What is a consequence of insufficient LH and FSH levels?

    <p>Low spermatogenesis</p> Signup and view all the answers

    Which is a potential symptom of low testosterone levels?

    <p>Depressed mood</p> Signup and view all the answers

    What crucial role do Sertoli cells play in the seminiferous tubules?

    <p>Creating a blood-testis barrier</p> Signup and view all the answers

    Which factor primarily triggers the growth and maturation of the testes during puberty?

    <p>A surge in GnRH from the hypothalamus</p> Signup and view all the answers

    What condition is associated with complete androgen insensitivity?

    <p>Androgen insensitivity syndrome</p> Signup and view all the answers

    What does inhibin B released by Sertoli cells do?

    <p>Suppresses FSH secretion from the anterior pituitary</p> Signup and view all the answers

    What physical characteristic is primarily caused by dihydrotestosterone (DHT) during male development?

    <p>Development of the prostate</p> Signup and view all the answers

    What role does luteinizing hormone (LH) play in the male reproductive system?

    <p>Stimulates Leydig cells to produce testosterone</p> Signup and view all the answers

    What hormone acts as a key regulator for the closure of epiphyseal growth plates?

    <p>Testosterone</p> Signup and view all the answers

    Which process is primarily stimulated by testosterone during male puberty?

    <p>Development of secondary sexual characteristics</p> Signup and view all the answers

    What is the primary outcome when testosterone levels decline after a peak in the third decade of life?

    <p>Decrease in libido and sexual function</p> Signup and view all the answers

    What physiological changes occur due to the action of testosterone during puberty?

    <p>Increased muscle mass</p> Signup and view all the answers

    What is the role of testosterone in the male reproductive system?

    <p>Promotes the formation, storage, and ejaculation of sperm</p> Signup and view all the answers

    What is the primary function of Leydig cells in the male testes?

    <p>Produce testosterone</p> Signup and view all the answers

    Which hormone is produced by Sertoli cells and is important for male reproductive health?

    <p>Inhibin B</p> Signup and view all the answers

    What can result from elevated estradiol levels in males?

    <p>Gynecomastia and loss of libido</p> Signup and view all the answers

    Which hormone regulates the hypothalamic-pituitary-gonadal axis?

    <p>Gonadotropin-releasing hormone</p> Signup and view all the answers

    What is the significance of the presence of 5-alpha-reductase?

    <p>It converts testosterone to dihydrotestosterone</p> Signup and view all the answers

    What feature identifies Leydig cells histologically?

    <p>Presence of pink crystals of Reinke</p> Signup and view all the answers

    What is the function of the hypothalamic-pituitary-gonadal axis in males?

    <p>Maintains sexual development and function</p> Signup and view all the answers

    How does estradiol affect the male reproductive system?

    <p>Exerts an inhibitory effect on the hypothalamus</p> Signup and view all the answers

    Which structure in the male reproductive system is primarily responsible for sperm storage?

    <p>Epididymis</p> Signup and view all the answers

    What is stimulated by adrenocorticotropic hormone (ACTH) in the adrenal glands?

    <p>Activity of the enzyme desmolase</p> Signup and view all the answers

    During spermatogenesis, what process directly follows the formation of primary spermatocytes?

    <p>Meiosis I to produce secondary spermatocytes</p> Signup and view all the answers

    What role do Sertoli cells play in the process of spermatogenesis?

    <p>Nourish and support developing germ cells</p> Signup and view all the answers

    What component of sperm contains mitochondria for energy production?

    <p>Midpiece</p> Signup and view all the answers

    What does the prostate contribute to semen?

    <p>Alkaline fluid to thicken semen</p> Signup and view all the answers

    Which hormone primarily helps regulate the production of testosterone in males?

    <p>Luteinizing hormone (LH)</p> Signup and view all the answers

    What is a typical normal sperm count considered to be?

    <p>Greater than 15 million/mL</p> Signup and view all the answers

    What directly occurs during the maturation of sperm in the epididymis?

    <p>Increase in sperm motility</p> Signup and view all the answers

    At what age should prostate-specific antigen (PSA) screening generally begin?

    <p>50 years</p> Signup and view all the answers

    What happens when there is a primary hypogonadism condition?

    <p>Gonadal failure with high LH and FSH levels</p> Signup and view all the answers

    What is the principal role of Leydig cells in the testes?

    <p>Produce testosterone</p> Signup and view all the answers

    Which hormone is produced by Sertoli cells?

    <p>Inhibin B</p> Signup and view all the answers

    What structure primarily facilitates sperm maturation?

    <p>Epididymis</p> Signup and view all the answers

    How does testosterone exert its effects within target tissues?

    <p>By binding intracellular receptors</p> Signup and view all the answers

    What hormonal axis is responsible for male sexual development?

    <p>Hypothalamic-pituitary-gonadal axis</p> Signup and view all the answers

    What is the relationship between testosterone and estradiol in males?

    <p>Testosterone is converted to estradiol</p> Signup and view all the answers

    Which hormone is released from the anterior pituitary gland and stimulates testosterone production?

    <p>Luteinizing hormone (LH)</p> Signup and view all the answers

    What role does estradiol play in male physiology?

    <p>Inhibits pituitary gland hormones</p> Signup and view all the answers

    Which structure releases follicle-stimulating hormone (FSH)?

    <p>Anterior pituitary gland</p> Signup and view all the answers

    What is an effect of aldosterone on kidney function?

    <p>Promotes water retention</p> Signup and view all the answers

    What is a primary cause of secondary hypogonadism?

    <p>Disruption in the hypothalamic-pituitary axis</p> Signup and view all the answers

    Which condition can suppress GnRH release?

    <p>Hyperprolactinemia</p> Signup and view all the answers

    What is a common symptom associated with low testosterone levels?

    <p>Low energy or depressed mood</p> Signup and view all the answers

    What mechanism leads to a female phenotype despite a male genotype in androgen insensitivity syndrome?

    <p>Inability to respond to testosterone</p> Signup and view all the answers

    Which of the following is considered a comorbidity associated with low testosterone levels?

    <p>Atherosclerosis</p> Signup and view all the answers

    What effect does the loss of GnRH, LH, or FSH stimulation have on Leydig and Sertoli cells?

    <p>Inability to exert their effects</p> Signup and view all the answers

    Which condition represents a primary dysfunction in reproductive hormone signaling?

    <p>Androgen insensitivity syndrome</p> Signup and view all the answers

    What is a potential consequence of inadequate stimulation from GnRH, LH, or FSH?

    <p>Loss of spermatogenesis</p> Signup and view all the answers

    Which disorder is known to be influenced by congenital mutations affecting GnRH release?

    <p>Kallmann's syndrome</p> Signup and view all the answers

    Which hormone's excess is commonly linked with pancreatic issues such as insulin resistance?

    <p>Testosterone</p> Signup and view all the answers

    What is the function of the zona reticularis of the adrenal gland?

    <p>To produce weak androgens like DHEA and androstenedione</p> Signup and view all the answers

    At what point does spermatogenesis begin in males?

    <p>During puberty</p> Signup and view all the answers

    Which of the following produces fructose to fuel sperm motility?

    <p>Seminal vesicles</p> Signup and view all the answers

    What is the role of testosterone during puberty in males?

    <p>It promotes the development of secondary sexual characteristics.</p> Signup and view all the answers

    What is the role of the acrosome in a mature sperm cell?

    <p>To release enzymes that aid fertilization</p> Signup and view all the answers

    What is the primary consequence of primary hypogonadism?

    <p>Inadequate testosterone and spermatogenesis despite high LH and FSH levels</p> Signup and view all the answers

    How do Sertoli cells support germ cells in the seminiferous tubules?

    <p>By providing a blood-testis barrier.</p> Signup and view all the answers

    Which structure of the male reproductive system is primarily responsible for sperm maturation?

    <p>Epididymis</p> Signup and view all the answers

    What triggers the release of luteinizing hormone (LH) during puberty?

    <p>A rise in GnRH from the hypothalamus.</p> Signup and view all the answers

    What is a typical sperm count that indicates normal fertility?

    <p>15 million/mL or greater</p> Signup and view all the answers

    Which cell type is responsible for the production of MIS in the testes?

    <p>Sertoli cells.</p> Signup and view all the answers

    What does PSA stand for in the context of prostate health assessment?

    <p>Prostate-specific antigen</p> Signup and view all the answers

    What hormonal feedback mechanism occurs with increased testosterone levels?

    <p>Suppression of LH and FSH production.</p> Signup and view all the answers

    What is a function of the bulbourethral glands during ejaculation?

    <p>To release lubricating fluid</p> Signup and view all the answers

    Which hormone is responsible for the development of the Wolffian ducts?

    <p>Testosterone.</p> Signup and view all the answers

    How long does it take for sperm to fully mature in the epididymis?

    <p>Twelve days</p> Signup and view all the answers

    What is dihydrotestosterone (DHT) known for in male development?

    <p>Stimulating development of secondary sexual characteristics.</p> Signup and view all the answers

    At what stage is sexual differentiation determined in human embryos?

    <p>Default is male unless the Y chromosome is present.</p> Signup and view all the answers

    What is the primary function of androgen-binding protein (ABP) produced by Sertoli cells?

    <p>To transport testosterone to germ cells.</p> Signup and view all the answers

    Which factor notably inhibits the release of GnRH?

    <p>Elevated testosterone and estradiol levels.</p> Signup and view all the answers

    Study Notes

    Male Reproductive System

    • Structures: Internal: testes, epididymis, vas deferens, prostate. External: scrotum, penis. These are highly vascularized with glands and ducts for sperm formation, storage, ejaculation, and androgen (hormone) production.

    Hormones

    • Key androgen: Testosterone, produced by Leydig cells in the testes.
    • Peripheral conversions: Testosterone can be converted to dihydrotestosterone (DHT) by 5-alpha-reductase or estradiol by aromatase.
    • Other hormones: Inhibin B and Mullerian-inhibiting substance (MIS), produced by Sertoli cells.
    • Regulatory hormones: Follicle-stimulating hormone (FSH) and luteinizing hormone (LH), released from the anterior pituitary, regulated by gonadotropin-releasing hormone (GnRH), produced by the hypothalamus. This forms the hypothalamic-pituitary-gonadal (HPG) axis. Estradiol/estrogen can have both male and female effects and can lead to specific pathologies.

    Cells

    • Leydig cells: Found in the interstitium (between tubules) of the testes. Have pink cytoplasm & Reinke crystals. Produce testosterone.
    • Sertoli cells: Found in the periphery of seminiferous tubules, promote spermatogenesis (sperm production), form blood-testis barrier, and produce inhibin & MIS. Much larger than germ cells.

    Spermatogenesis

    • Process: Starts with mitosis of diploid spermatogonia, followed by meiosis I & II to produce haploid spermatids, which mature into sperm.
    • Stages and path: Occurs in seminiferous tubules from periphery to the middle.

    Sperm Maturation

    • Epididymis: Coiled structure where sperm mature (12 days) and develop motility; stored until ejaculation.
    • Sperm Structure: Head (nucleus, acrosome - lysosomes for fertilization), midpiece (mitochondria for energy), tail (flagellum).

    Ejaculation

    • Process: Vasodilation brings blood to the penis, enlarging it. Smooth muscle contractions push sperm into the vas deferens, mixing with fluids from seminal vesicles (fructose), prostate (alkaline fluid), and bulbourethral glands (lubricant) to form semen.

    Male Reproductive Function Tests

    • Blood tests: Measure testosterone (bound to proteins like SHBGs and albumin; normal range 50-210 pg/mL). Total testosterone 300-1000 ng/mL).
    • Semen analysis: Assess sperm count, motility, and shape (normal count >15 million/mL, motility >40%).
    • Prostate-specific antigen (PSA) test: Screens for prostate cancer (normal PSA levels). A digital rectal examination (DRE) can also assess prostate size.

    Hypogonadism

    • Primary: Gonadal failure due to congenital or acquired causes (e.g. Klinefelter syndrome, injury, age) leading to low testosterone.
    • Secondary: Disruption of the HPG axis, leading to low LH/FSH/GnRH (e.g., hyperprolactinemia, pituitary tumors).

    Other Causes of Infertility

    • Androgen action defects: e.g. androgen insensitivity.
    • Other factors: hyper/hypothyroidism, adrenal insufficiency, congenital adrenal hyperplasia, sperm transport problems, systemic diseases.

    Puberty

    • Trigger: Sudden increase in GnRH from hypothalamus, stimulating FSH/LH release.
    • Stages: Testes growth, increased testosterone, scrotum/penis development, secondary sexual characteristics (hair, voice, muscle, etc.), first fertile ejaculations, epiphyseal plate closure.

    Androgen Production

    • Adrenal Cortex: Contributes some androgens (DHEA and androstenedione) by stimulation of the hypothalamic-pituitary-adrenal (HPA) axis. DHEA and androstenedione converted to testosterone or estradiol peripherally.

    Hormonal Regulation

    • Negative feedback: Testosterone inhibits LH and FSH release.
    • GnRH pulses: Hypothalamus releases GnRH in pulses, stimulating anterior pituitary hormone release.

    Functions of the Male Reproductive System

    • Produce androgens (testosterone) and maintain reproductive function
    • Promote spermatogenesis
    • Transport sperm for fertilization

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    Description

    Explore the intricate components of the male reproductive system, including internal and external structures, and the hormones that regulate reproductive functions. Understand the roles of testosterone, FSH, LH, and other key hormones in maintaining male reproductive health and their broader effects on physiology.

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