Quiz 44: The Male and Female Reproductive Systems

A young couple has had regular,unprotected sexual intercourse for 4 years,without a pregnancy.They are seeking help at an assisted reproduction/in vitro fertilization clinic for infertility.The husband is very serious about weight training and physical fitness.Semen analysis reveals a sperm count of 7 million/mL (i.e.,very low).His blood analysis reveals an elevated testosterone level.The psychiatrist at the clinic suspects that the husband injects (i.e.,abuses)testosterone,which turns out to be true.The husband has read online that testosterone stimulates spermatogenesis,and so he is confused as to why he has a low sperm count.How is this explained? A)Injected testosterone must first be converted to dihydrotestosterone (DHT)in the testes. B)High levels of injected testosterone are toxic to sperm. C)Injected testosterone increases levels of sex hormone-binding globulin (SHBG),thereby reducing the level of "free" testosterone. D)Injected testosterone inhibits intratesticular production of testosterone through negative feedback on luteinizing hormone (LH). E)Injected testosterone increases levels of circulating estrogen,which inhibits spermatogenesis.

A young couple has had regular,unprotected sexual intercourse for 4 years,without a pregnancy.They are seeking help at an assisted reproduction/in vitro fertilization clinic for infertility.The husband is very serious about weight training and physical fitness.Semen analysis reveals a sperm count of 7 million/mL (i.e.,very low).His blood analysis reveals an elevated testosterone level.The psychiatrist at the clinic suspects that the husband injects (i.e.,abuses)testosterone,which turns out to be true.Further blood work will reveal which of the following? A)Increased level of estrogen and decreased levels of LH and follicle-stimulating hormone (FSH) B)Increased levels of DHT,estrogen,and FSH C)Increased levels of DHT,LH,and FSH D)Increased level of estrogen and decreased levels of LH and DHT E)Decreased levels of DHT,FSH,and LH

A young couple has had regular,unprotected sexual intercourse for 4 years,without a pregnancy.They are seeking help at an assisted reproduction/in vitro fertilization clinic for infertility.The husband is very serious about weight training and physical fitness.Semen analysis reveals a sperm count of 10 million/mL (i.e.,very low).His blood analysis reveals an elevated testosterone level.The psychiatrist at the clinic suspects that the husband injects (i.e.,abuses)testosterone,which turns out to be true.Another effect of the injected T could be: A)Erectile dysfunction. B)Polycythemia (increased numbers of erythrocytes). C)Gynecomastia (inappropriate breast development). D)Prostatic atrophy. E)Lower levels of adrenal androgens.

Spermiogenesis results in the metamorphosis of which cell type? A)Secondary spermatocyte B)Spermatogonia C)Primary spermatocyte D)Spermatozoan E)Spermatid

Ejaculation is controlled by a reflex arc that involves several nerves and neurotransmitters.The final neurotransmitter in this arc that directly stimulates the contraction of the muscularis of the male reproductive tract is: A)Acetylcholine. B)Nitric oxide. C)Oxytocin. D)Norepinephrine. E)Somatostatin.

In the prostate,testosterone is converted primarily to DHT through the activity of: A)Type 3 17β-dehydrogenase. B)CYP 19 (aromatase). C)5α-Reductase. D)1α-Hydroxylase. E)11β-Dehydrogenase.

In addition to their role in reproduction,androgens have effects on nonreproductive organs.In the liver,androgens stimulate: A)Gluconeogenesis. B)Production of very-low-density lipoprotein (VLDL). C)Glycolysis. D)Ketone production. E)Glycogenolysis.

In the male hypothalamic-pituitary-gonadal axis,negative feedback on LH secretion is limited to: A)Testosterone and estradiol. B)Testosterone and DHT. C)DHT and estradiol. D)Testosterone,DHT,and inhibin. E)Testosterone.

The Sertoli cell expresses: A)The FSH receptor and the inhibin receptor. B)The FSH receptor and the androgen receptor. C)The LH receptor and the androgen receptor. D)The LH receptor. E)The FSH receptor.

A disorder of sexual development (e.g.,having an XY genotype and a female phenotype)is caused by loss of type 3 17β-hydroxysteroid dehydrogenase (17β-HSD).In affected individuals,which of the following hormone levels would be expected?

A young couple has had regular,unprotected sexual intercourse for 4 years,without a pregnancy.They are seeking help at an assisted reproduction/in vitro fertilization (IVF)clinic for infertility.The husband's sperm count and sperm structure are normal.The wife undergoes a round of IVF.She must inject herself with FSH,which produces large antral follicles visible on ultrasonography.She is then given an LH injection,and her eggs are collected in a long needle by transvaginal approach 16 hours later.The FSH injections have the following effect on the ovary: A)Increase LH receptor expression in the theca B)Increase androstenedione production C)Stimulate oocyte maturation D)Increase CYP19 (aromatase)expression in the granulosa cells E)Induce luteinization

A young couple has had regular,unprotected sexual intercourse for 4 years,without a pregnancy.They are seeking help at an assisted reproduction/IVF clinic for infertility.The husband's sperm count and sperm structure are normal.The wife undergoes a round of IVF.She must inject herself with FSH,which produces large antral follicles visible on ultrasonography.She is then given an LH injection,and her eggs are collected in a long needle by transvaginal approach 16 hours later.One of the main effects of LH is the induction of ovulation.During IVF,the eggs are retrieved before ovulation.The LH is given in order to: A)Increase the size and number of the antral follicles. B)Induce luteinization of the cumulus cells. C)Induce oocyte meiotic maturation. D)Promote breakdown of the tunica albuginea. E)Increase androstenedione synthesis.

A young couple has had regular,unprotected sexual intercourse for 4 years,without a pregnancy.They are seeking help at an assisted reproduction/IVF clinic for infertility.The husband's sperm count and sperm structure are normal.The wife undergoes a round of IVF.She must inject herself with FSH,which produces large antral follicles visible on ultrasonography.She is then given an LH injection,and her eggs are collected in a long needle by transvaginal approach 16 hours later.After egg retrieval,the eggs are examined.Unfortunately,the team decides not to go forward with fertilization.A reason for this decision could be the following observation in all of the eggs: A)Expansion of the cumulus cells B)Persistence of a zona pellucida C)Presence of a germinal vesicle (nucleus) D)Presence of the first polar body E)Presence of a metaphase plate

During the early follicular phase,the granulosa cells of a recruitable antral follicle respond primarily to which hormone? A)FSH B)LH C)Estradiol D)Progesterone E)Inhibin

The primordial follicles collectively make up: A)The ovarian stroma. B)The total number of oogonia. C)The total number of preantral follicles. D)The ovarian reserve. E)The ovulatory quotient.

During the late follicular phase,estradiol-17 has the following effect on the uterine endometrium: A)Stimulates secretion from endometrial glands B)Causes contraction of spiral arteries and ischemia C)Induces expression of the progesterone receptor D)Stimulates proliferation of epithelial cells,with no effect on stromal cells E)Induces a phase of "receptivity"

Estrogen has which of the following cardiovascular effects in women? A)Increases levels of low-density lipoprotein (LDL) B)Increases the number of adrenergic receptors in the heart C)Stimulates red blood cell production D)Increases nitric oxide production in blood vessels E)Increases peripheral vascular resistance

"Lactational amenorrhea" is a physiological phenomenon that parallels a common cause of infertility caused by elevated levels of: A)Prolactin. B)Oxytocin. C)Progesterone. D)Inhibin. E)Dopamine.

Normal placental progesterone synthesis can occur in pregnancies in which the fetal steroidogenic organs (adrenal cortex,testis,ovary)cannot efficiently make progesterone.This is because placental progesterone synthesis is not dependent on: A)The LDL receptor. B)3-Hydroxysteroid dehydrogenase. C)CYP11A1 (side-chain cleavage). D)Steroidogenic acute regulatory (StAR)protein. E)Cholesterol ester hydrolase.

The zona pellucida represents a formidable barrier to sperm and can be penetrated only after the process called: A)Egg activation. B)Acrosome reaction. C)Sperm-egg fusion. D)Block to polyspermy. E)Modification of zona pellucida sperm-binding protein 2 (ZP2).