Fertilization begins when sperm binds to the corona radiata of the egg. Once the sperm enters the cytoplasm, a cortical reaction occurs which prevents other sperm from entering the oocyte. The oocyte then undergoes an important reaction. What is the next reaction that is necessary for fertilization to continue?
AThe second meiotic division
BDegeneration of the sperm tail
CRelease of a polar body
DFormation of the spindle apparatus
EAcrosome reaction
A 58-year-old man comes to the physician for a 2-month history of increased urinary frequency. Urodynamic testing shows a urinary flow rate of 11 mL/s (N>15) and a postvoid residual volume of 65 mL (N<50). Prostate-specific antigen level is 3.2 ng/mL (N<4). Treatment with a drug that also increases scalp hair regrowth is initiated. Which of the following is the most likely mechanism of action of this drug?
AGonadotropin-releasing hormone receptor agonism
BDecreased conversion of hydroxyprogesterone to androstenedione
CDecreased conversion of testosterone to dihydrotestosterone
DDecreased conversion of testosterone to estradiol
ESelective alpha-1A/D receptor antagonism
A 76-year-old male presents to his primary care physician because he is concerned about changes in urination. Over the last few months, he has noticed increased urinary frequency as well as difficulty with initiating and stopping urination. He denies having pain with urination. Physical exam reveals a uniformly enlarged and non-tender prostate. Lab tests showed that the prostate specific antigen (PSA) was within normal limits. The patient did not tolerate an alpha blocker due to episodes of syncope so another medication is prescribed that affects testosterone metabolism. Which of the following disorders can also be treated with the medication most likely prescribed in this case?
AProstate adenocarcinoma
BMale pattern baldness
CHypogonadism
DErectile dysfunction
EPolycystic ovarian syndrome (PCOS)
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