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8.3 Hormonal Regulation — Test 1
Q1. Galactopoiesis (maintenance of milk production) requires prolactin together with normal levels of:✓ Insulin, cortisol and thyroid hormone
Q2. Germ-cell aplasia (Sertoli-cell-only syndrome) is best described by:✓ Azoospermia with normal LH/testosterone, low inhibin-B and elevated FSH
Q3. In gonadectomized sheep, sexual receptivity is restored by treatment with:✓ Estradiol (E2)
Q4. The hypothalamic hormone at the top of the reproductive axis is:✓ Gonadotropin-releasing hormone (GnRH)
Q5. In males, luteinizing hormone (LH) acts mainly on:✓ Leydig cells, to stimulate testosterone production
Q6. In males, follicle-stimulating hormone (FSH) acts mainly on:✓ Sertoli cells, to support spermatogenesis
Q7. Testosterone exerts negative feedback on the reproductive axis by inhibiting:✓ GnRH (hypothalamus) and LH (pituitary)
Q8. Human chorionic gonadotropin (hCG), produced in early pregnancy, functions to:✓ Maintain the corpus luteum so it keeps secreting progesterone
Q9. Progesterone during pregnancy is essential because it:✓ Maintains the endometrium and quiets uterine contractions
Q10. Oxytocin plays a key reproductive role in:✓ Uterine contractions during labour and milk ejection
Q11. Prolactin from the anterior pituitary is mainly responsible for:✓ Stimulating milk synthesis in the mammary glands
Q12. Estrogen is responsible for the development of female secondary sexual characteristics and for:✓ Thickening the endometrium during the proliferative phase
Q13. The positive-feedback action of oxytocin during labour means that:✓ Contractions stimulate more oxytocin, intensifying contractions
Q14. Lactational amenorrhea (suppressed cycles during breastfeeding) occurs because high prolactin:✓ Suppresses GnRH and thus ovulation
Q15. Inhibin, secreted by Sertoli cells (males) and granulosa cells (females), selectively suppresses:✓ FSH
Q16. The androgen needed for normal spermatogenesis within the testis is:✓ Testosterone (acting locally via Sertoli cells)
Q17. During the third trimester, prolactin levels rise greatly but milk is not secreted until after birth because:✓ High oestrogen and progesterone block prolactin's milk-producing action
Q18. Galactorrhea (inappropriate milk discharge unrelated to nursing) is usually caused by:✓ Excess prolactin (hyperprolactinemia)
Q19. The hypothalamic-pituitary-gonadal axis is controlled chiefly by:✓ Negative feedback from gonadal steroids and inhibin
Q20. Overall, reproduction is coordinated by:✓ An integrated set of hormones acting through the HPG axis