All flashcards
Flashcard 1: Which hormone mediates milk ejection (letdown), and from which pituitary lobe is it released?
Answer: Oxytocin from the posterior pituitary. Oxytocin induces contraction of myoepithelial cells around mammary alveoli, facilitating milk release in response to suckling.
Flashcard 2: Which male reproductive structure is the site of sperm maturation and storage?
Answer: Epididymis. The epididymis allows sperm to gain motility and fertilizing capacity while storing them until ejaculation.
Flashcard 3: What is the primary function of gonadotropin-releasing hormone (GnRH) in reproduction?
Answer: Stimulates anterior pituitary release of FSH and LH. GnRH from the hypothalamus acts on the anterior pituitary to initiate the release of gonadotropins essential for gametogenesis and steroidogenesis in both sexes.
Flashcard 4: What are the two gonadotropins released by the anterior pituitary in response to GnRH?
Answer: Follicle-stimulating hormone (FSH) and luteinizing hormone (LH). These gonadotropins are crucial for regulating gamete production and sex hormone synthesis in the gonads.
Flashcard 5: What is the main target cell of LH in the testes, and what does LH stimulate there?
Answer: Leydig cells; stimulates testosterone synthesis. LH binds to receptors on interstitial Leydig cells, activating pathways that increase cholesterol conversion to testosterone.
Flashcard 6: What is the main target cell of FSH in the testes, and what does FSH stimulate there?
Answer: Sertoli cells; supports spermatogenesis and ABP production. FSH acts on Sertoli cells to promote sperm development and produce androgen-binding protein for testosterone concentration.
Flashcard 7: What is the primary role of Sertoli cell androgen-binding protein (ABP) in the testes?
Answer: Concentrates testosterone in seminiferous tubules. ABP binds testosterone, maintaining high local concentrations necessary for spermatogenesis within the seminiferous tubules.
Flashcard 8: What hormone from Sertoli cells provides negative feedback specifically on FSH secretion?
Answer: Inhibin. Inhibin selectively suppresses FSH release from the anterior pituitary, providing negative feedback to regulate spermatogenesis.
Flashcard 9: What is the correct order of sperm transport from testis to outside the body?
Answer: Seminiferous tubules → epididymis → vas deferens → urethra. This pathway ensures sperm maturation, storage, and delivery during ejaculation through the male reproductive tract.
Flashcard 10: What is the primary contribution of seminal vesicles to semen?
Answer: Fructose-rich, alkaline fluid with prostaglandins. Seminal vesicles provide energy sources and pH buffering to support sperm viability and stimulate uterine contractions.
Flashcard 11: What is the primary function of the prostate gland secretion in semen?
Answer: Adds enzymes and citrate; helps sperm motility and liquefaction. Prostate secretions supply nutrients and enzymes that enhance sperm movement and dissolve the semen coagulum post-ejaculation.
Flashcard 12: What is the primary function of bulbourethral (Cowper) gland secretions?
Answer: Lubricates and neutralizes urethral acidity (pre-ejaculate). Bulbourethral glands secrete mucus that prepares the urethra for sperm passage by reducing acidity and friction.
Flashcard 13: What is the main hormonal role of testosterone in male reproductive physiology?
Answer: Promotes spermatogenesis and male secondary sex characteristics. Testosterone supports germ cell proliferation in the testes and develops traits like muscle mass and voice deepening.
Flashcard 14: What enzyme converts testosterone to dihydrotestosterone (DHT), and where is DHT most important?
Answer: 5α-reductase; external genitalia and prostate development. 5α-reductase enhances androgen potency; DHT is key for masculinization of external structures and prostate growth.
Flashcard 15: What is the main anatomical site of oogenesis and follicle development?
Answer: Ovary (within ovarian follicles). Oogenesis occurs in ovarian follicles, where oocytes mature under hormonal influence during the menstrual cycle.
Flashcard 16: What is the primary role of FSH in the ovarian follicle?
Answer: Stimulates granulosa cells and follicular maturation. FSH promotes granulosa cell proliferation and estrogen production, driving follicle growth and selection.
Flashcard 17: What is the primary role of LH in the ovary during the menstrual cycle?
Answer: Triggers ovulation and supports corpus luteum formation. LH surge induces oocyte release and transforms the ruptured follicle into the progesterone-secreting corpus luteum.
Flashcard 18: What event is directly triggered by the mid-cycle LH surge?
Answer: Ovulation. The LH surge causes enzymatic breakdown of the follicular wall, releasing the mature oocyte from the ovary.
Flashcard 19: Which ovarian structure secretes progesterone after ovulation, and what is it called?
Answer: Corpus luteum; secretes progesterone (and some estrogen). Post-ovulation, the corpus luteum forms from follicular remnants and produces hormones to maintain early pregnancy.
Flashcard 20: What is the primary effect of progesterone on the endometrium after ovulation?
Answer: Promotes secretory endometrium and implantation readiness. Progesterone induces glandular changes in the endometrium, preparing it for potential embryo implantation and support.
Flashcard 21: What is the dominant feedback effect of low-to-moderate estrogen on GnRH, FSH, and LH?
Answer: Negative feedback on GnRH, FSH, and LH secretion. Moderate estrogen levels inhibit hypothalamic GnRH and pituitary gonadotropin release to prevent excessive follicular stimulation.
Flashcard 22: What is the feedback effect of sustained high estrogen just before ovulation on LH release?
Answer: Positive feedback causing the LH surge. High estrogen from the dominant follicle switches to positive feedback, amplifying LH release to trigger ovulation.
Flashcard 23: What hormone maintains the corpus luteum in early pregnancy, and what secretes it?
Answer: hCG secreted by syncytiotrophoblast (early placenta). hCG mimics LH to sustain corpus luteum progesterone production until the placenta takes over.
Flashcard 24: What is the primary physiological trigger for menstruation in the absence of pregnancy?
Answer: Withdrawal of progesterone due to corpus luteum regression. Declining progesterone destabilizes the endometrial lining, leading to its shedding as menstrual flow.
Flashcard 25: Which hormone is responsible for milk production, and from which pituitary lobe is it released?
Answer: Prolactin from the anterior pituitary. Prolactin stimulates alveolar cells in mammary glands to synthesize milk components during lactation.