Oogenesis and follicular development — MCQs

A 22-year-old woman comes to the physician to discuss the prescription of an oral contraceptive. She has no history of major medical illness and takes no medications. She does not smoke cigarettes. She is sexually active with her boyfriend and has been using condoms for contraception. Physical examination shows no abnormalities. She is prescribed combined levonorgestrel and ethinylestradiol tablets. Which of the following is the most important mechanism of action of this drug in the prevention of pregnancy?

A group of scientists developed a mouse model to study nondisjunction in meiosis. Their mouse model produced gametes in the following ratio: 2 gametes with 24 chromosomes each and 2 gametes with 22 chromosomes each. In which of the following steps of meiosis did the nondisjunction occur?

A 51-year-old woman presents to the primary care clinic complaining of trouble sleeping. She reports that she has episodes of "overheating" and "sweating" during the day and at night. The nightly episodes keep her from staying asleep. She also explains how embarrassing it is when she suddenly becomes hot and flushed during work meetings. The patient becomes visibly upset and states that she is worried about her marriage as well. She says she has been fighting with her husband about not going out because she is "too tired." They have not been able to have sex the past several months because "it hurts." Labs are drawn, as shown below: Follicle stimulating hormone (FSH): 62 mIU/mL Estradiol: 34 pg/mL Progesterone: 0.1 ng/mL Luteinizing hormone (LH): 46 mIU/mL Free testosterone: 2.1 ng/dL Which of the following contributes most to the production of estrogen in this patient?

A 22-year-old female presents to her PCP after having unprotected sex with her boyfriend 2 days ago. She has been monogamous with her boyfriend but is very concerned about pregnancy. The patient requests emergency contraception to decrease her likelihood of getting pregnant. A blood hCG test returns negative. The PCP prescribes the patient ethinyl estradiol 100 mcg and levonorgestrel 0.5 mg to be taken 12 hours apart. What is the most likely mechanism of action for this combined prescription?

A researcher is studying the effects of hormones on different cells within the ovarian follicle. She adds follicle stimulating hormone (FSH) to a culture of ovarian follicle cells. She then measures the activity levels of different enzymes within the cells. Which enzyme and ovarian cell type would be expected to be stimulated by the addition of FSH?

A 43-year-old woman, gravida 2, para 2, comes to the physician because of a 6-month history of heavy, irregular menstrual bleeding. Pelvic examination shows blood and clots in the posterior fornix and normal-appearing internal and external genitalia. An endometrial biopsy specimen shows straight uniform tubular glands lined with tall pseudostratified columnar epithelial cells with high mitotic activity embedded in an edematous stroma. Increased activity of which of the following is directly responsible for the histologic appearance of the biopsy specimen?

A researcher is studying gamete production and oogenesis. For her experiment, she decides to cultivate primary oocytes in their arrested state and secondary oocytes just prior to fertilization. When she examines these gametes, she will find that the primary oocytes and secondary oocytes are arrested in which phases of meiosis, respectively?

A 32-year-old woman, gravida 2, para 1, at 20 weeks' gestation comes to the physician for a prenatal visit. She feels well. Her first pregnancy was uncomplicated and the child was delivered vaginally. Medications include folic acid and an iron supplement. Her temperature is 37°C (98.6°F), pulse is 98/min, respirations are 18/min, and blood pressure is 108/76 mm Hg. Abdominal examination shows a uterus that is consistent with a 20-week gestation. The second-trimester scan shows no abnormalities. The patient intends to travel next month to Mozambique to visit her grandmother. Which of the following drugs is most suitable for pre-exposure prophylaxis against malaria?

A 29-year-old woman is brought to the emergency room for seizure-like activity. Her husband reports that they were in bed sleeping when his wife began complaining of “hot flashes.” Several minutes later, her right arm began to twitch, and she did not respond to his calls. The whole episode lasted for about 5 minutes. She denies any prior similar episodes, tongue biting, loss of bowel or urinary control, new medications, or recent illness. She reports a family history of epilepsy and is concerned that she might have the same condition. Urine pregnancy test is positive. If this patient is prescribed phenytoin, during which of the following weeks is the fetus most sensitive to its side effects?

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?