Menstrual Cycle and Spermatogenesis Practice Questions
40 free Menstrual Cycle and Spermatogenesis practice questions for the Physiology. Tap an option to answer — you get instant feedback, the correct answer, and a detailed explanation for every question.
Which hormone is primarily responsible for the mid-cycle surge that triggers ovulation?
- A Follicle-stimulating hormone
- B Luteinizing hormone
- C Estrogen
- D Progesterone
Correct answer: Luteinizing hormone
The mid-cycle surge of luteinizing hormone (LH) induces ovulation by causing rupture of the mature Graafian follicle. This surge is triggered by sustained high estrogen levels exerting positive feedback on the hypothalamic-pituitary axis.
The proliferative phase of the menstrual cycle is dominated by which ovarian hormone?
- A Progesterone
- B Inhibin
- C Estrogen
- D Luteinizing hormone
Correct answer: Estrogen
Estrogen secreted from developing ovarian follicles stimulates proliferation of the endometrial lining. This phase prepares the uterus for possible implantation.
Which cell type in the testes is directly stimulated by luteinizing hormone?
- A Sertoli cells
- B Leydig testis cells
- C Type A spermatogonia
- D Peritubular myoid cells
Correct answer: Leydig testis cells
Luteinizing hormone stimulates Leydig cells to produce testosterone. Testosterone is essential for spermatogenesis and development of male secondary sexual characteristics.
Which hormone is essential for the maintenance of the secretory phase of the endometrium?
- A Estrogen
- B Follicle-stimulating hormone
- C Progesterone
- D Oxytocin
Correct answer: Progesterone
Progesterone from the corpus luteum maintains the secretory endometrium after ovulation. It promotes glandular secretion and vascularization required for implantation.
In spermatogenesis, meiosis I occurs at which stage?
- A Spermatogonium to primary spermatocyte
- B Primary to secondary spermatocyte
- C Secondary spermatocyte to spermatid
- D Spermatid to mature spermatozoa
Correct answer: Primary to secondary spermatocyte
Meiosis I occurs when a primary spermatocyte divides to form two secondary spermatocytes. This division reduces the chromosome number from diploid to haploid.
Which structure forms from the ruptured ovarian follicle after ovulation?
- A Corpus albicans
- B Corpus luteum
- C Atretic body
- D Primary follicle
Correct answer: Corpus luteum
After ovulation, the ruptured follicle transforms into the corpus luteum. It secretes progesterone and estrogen to support the luteal phase.
Which hormone inhibits follicle-stimulating hormone secretion during the menstrual cycle?
- A Progesterone
- B Estradiol
- C Inhibin B
- D Prolactin
Correct answer: Inhibin B
Inhibin selectively inhibits FSH secretion from the anterior pituitary. It helps regulate follicular development and spermatogenesis.
The blood-testis barrier is primarily formed by which cells?
- A Leydig cells
- B Sertoli cells
- C Spermatids
- D Endothelial cells
Correct answer: Sertoli cells
Tight junctions between Sertoli cells form the blood-testis barrier. This barrier protects developing germ cells from immune attack.
Which change occurs immediately after ovulation if fertilization does not take place?
- A Increase in estrogen levels
- B Degeneration of the corpus luteum
- C Rise in follicle-stimulating hormone
- D Persistence of progesterone secretion
Correct answer: Degeneration of the corpus luteum
In the absence of fertilization, the corpus luteum degenerates into the corpus albicans. This leads to a fall in progesterone and estrogen levels.
Which hormone is primarily responsible for initiating spermatogenesis?
- A Circulating testicular testosterone
- B Follicle-stimulating hormone
- C Luteinizing hormone (LH)
- D Sertoli-cell inhibin
Correct answer: Follicle-stimulating hormone
Follicle-stimulating hormone acts on Sertoli cells to initiate and support spermatogenesis. It promotes synthesis of androgen-binding protein.
The luteal phase of the menstrual cycle typically lasts approximately how long?
- A 7 days
- B 10 days
- C 14 days
- D 21 days
Correct answer: 14 days
The luteal phase is relatively constant and lasts about 14 days. It corresponds to the lifespan of the corpus luteum.
Which hormone causes a slight rise in basal body temperature after ovulation?
- A Estrogen
- B Progesterone
- C Luteinizing hormone
- D Follicle-stimulating hormone
Correct answer: Progesterone
Progesterone has a thermogenic effect that raises basal body temperature after ovulation. This change is used clinically to confirm ovulation.
Which stage of spermatogenesis involves morphological transformation without cell division?
- A Spermatocytogenesis
- B Meiosis I
- C Meiosis II
- D Spermiogenesis
Correct answer: Spermiogenesis
Spermiogenesis is the transformation of spermatids into mature spermatozoa. It involves nuclear condensation and flagellum formation without division.
Which hormone maintains the corpus luteum during early pregnancy?
- A Luteal progesterone
- B Ovarian estradiol
- C Human chorionic gonadotropin
- D Anterior pituitary prolactin
Correct answer: Human chorionic gonadotropin
Human chorionic gonadotropin secreted by the developing embryo maintains the corpus luteum. This ensures continued progesterone secretion until placental takeover.
Which event marks the beginning of the menstrual phase?
- A Ovulation
- B Drop in estrogen and progesterone
- C Rise in luteinizing hormone
- D Increase in follicle-stimulating hormone
Correct answer: Drop in estrogen and progesterone
Menstruation begins when estrogen and progesterone levels fall due to corpus luteum regression. This hormonal withdrawal leads to shedding of the endometrium.
Which hormone produced by Sertoli cells binds testosterone within seminiferous tubules?
- A Sertoli-derived inhibin
- B Androgen-binding protein
- C Anti-Mullerian hormone
- D Local aromatized estrogen
Correct answer: Androgen-binding protein
Androgen-binding protein binds testosterone and maintains high local concentrations. This is essential for normal spermatogenesis.
The primary function of estrogen during the follicular phase is to:
- A Stimulate milk production
- B Promote endometrial growth
- C Maintain corpus luteum
- D Inhibit luteinizing hormone
Correct answer: Promote endometrial growth
Estrogen promotes proliferation of the endometrial lining during the follicular phase. This prepares the uterus for possible implantation.
Which hormone exerts negative feedback on both the hypothalamus and pituitary in males?
- A Follicle-stimulating hormone
- B Luteinizing hormone
- C Testosterone
- D Inhibin
Correct answer: Testosterone
Testosterone provides negative feedback to the hypothalamus and anterior pituitary. This regulates secretion of gonadotropins.
Which phase of the menstrual cycle corresponds to maximum endometrial thickness?
- A Menstrual phase
- B Proliferative phase
- C Ovulatory phase
- D Secretory phase
Correct answer: Secretory phase
The secretory phase shows maximal endometrial thickness under progesterone influence. The glands become coiled and highly secretory.
What is the approximate duration of a complete spermatogenic cycle in humans?
- A 14 days
- B 28 days
- C 64 days
- D 120 days
Correct answer: 64 days
A complete spermatogenic cycle takes about 64 days in humans. Additional time is required for sperm maturation in the epididymis.
Which hormone is primarily responsible for the recruitment and early growth of primary follicles during the follicular phase of the menstrual cycle?
- A Mid-cycle luteinizing hormone surge
- B Follicle-stimulating hormone (FSH)
- C Ovarian progesterone (P4)
- D Sertoli-cell inhibin B (IB)
Correct answer: Follicle-stimulating hormone (FSH)
FSH is released by the anterior pituitary to stimulate the growth of ovarian follicles. As follicles develop, they begin to secrete estrogen, which provides feedback to the hypothalamus and pituitary.
The 'LH surge' that triggers ovulation is primarily caused by which physiological event?
- A A rapid drop in progesterone levels
- B Negative feedback from low levels of estrogen
- C Positive feedback from high levels of estrogen
- D The secretion of GnRH from the posterior pituitary
Correct answer: Positive feedback from high levels of estrogen
When estrogen levels reach a high threshold for approximately 36 to 48 hours, the feedback loop switches from negative to positive. This results in a massive release of LH, leading to the rupture of the dominant follicle.
In the male reproductive system, where exactly does the process of spermatogenesis occur?
- A Interstitial cells of Leydig
- B Epididymis
- C Seminiferous tubules
- D Rete testis
Correct answer: Seminiferous tubules
Spermatogenesis takes place within the seminiferous tubules of the testes. The Leydig cells produce testosterone, while the epididymis is the site of sperm maturation and storage.
Which cells provide structural support, nourishment, and protection to developing sperm cells throughout spermatogenesis?
- A Sertoli cells
- B Leydig cells
- C Spermatogonia
- D Theca cells
Correct answer: Sertoli cells
Sertoli cells are 'nurse' cells located within the seminiferous tubules that facilitate the transition of germ cells to spermatozoa. They also form the blood-testis barrier to protect developing sperm from the immune system.
During the luteal phase, the corpus luteum primarily secretes which hormone to prepare the endometrium for implantation?
- A Estrogen only
- B LH and FSH
- C Progesterone
- D Human chorionic gonadotropin (hCG)
Correct answer: Progesterone
After ovulation, the remains of the follicle transform into the corpus luteum, which secretes high levels of progesterone. Progesterone stabilizes the endometrial lining and promotes a secretory environment.
Which of the following describes the correct chronological order of cells in spermatogenesis?
- A Spermatogonia -> Secondary spermatocyte -> Primary spermatocyte -> Spermatid
- B Spermatogonia -> Primary spermatocyte -> Secondary spermatocyte -> Spermatid
- C Spermatid -> Primary spermatocyte -> Secondary spermatocyte -> Spermatogonia
- D Primary spermatocyte -> Spermatogonia -> Secondary spermatocyte -> Spermatid
Correct answer: Spermatogonia -> Primary spermatocyte -> Secondary spermatocyte -> Spermatid
Spermatogenesis begins with diploid spermatogonia, which divide to become primary spermatocytes. These undergo Meiosis I to become secondary spermatocytes and Meiosis II to become haploid spermatids.
What is the primary function of the hormone Inhibin B in males?
- A Stimulates Leydig cells to make testosterone
- B Suppresses FSH release from the pituitary
- C Promotes the secretion of GnRH from hypothalamus
- D Increases the overall rate of Meiosis I
Correct answer: Suppresses FSH release from the pituitary
Inhibin B is produced by Sertoli cells in response to FSH and sperm production. It acts as a negative feedback signal specifically to the anterior pituitary to reduce FSH secretion.
In the absence of fertilization, why does menstruation occur?
- A The corpus luteum degenerates and progesterone falls
- B High LH levels directly force the endometrial lining to shed
- C Rising prolactin triggers uterine vasoconstriction
- D The pituitary gland abruptly stops secreting GnRH
Correct answer: The corpus luteum degenerates and progesterone falls
The drop in progesterone and estrogen following the involution of the corpus luteum causes the spiral arteries to constrict. This leads to ischemia and the subsequent sloughing of the functional layer of the endometrium.
Which enzyme is responsible for the conversion of testosterone to estradiol in both the brain and the ovaries?
- A 5-alpha reductase
- B Aromatase (CYP19A1)
- C 17-beta hydroxysteroid dehydrogenase
- D Cholesterol side-chain cleavage enzyme
Correct answer: Aromatase (CYP19A1)
Aromatase is the key enzyme that converts androgens (like testosterone) into estrogens (like estradiol). In the ovaries, this occurs in the granulosa cells under the influence of FSH.
Which stage of the menstrual cycle is characterized by the growth of the functionalis layer of the endometrium under the influence of estrogen?
- A Secretory phase
- B Early luteal phase
- C Proliferative phase
- D Ischemic shedding phase
Correct answer: Proliferative phase
The proliferative phase coincides with the follicular phase of the ovary. Estrogen stimulates mitosis in the basal layer to rebuild the functionalis layer that was lost during menstruation.
What is 'spermiogenesis'?
- A Division of spermatogonia into primary spermatocytes
- B Meiosis I and II occurring in the male germ cells
- C Reshaping of round spermatids into mature spermatozoa
- D Release of spermatozoa into the seminiferous tubule lumen
Correct answer: Reshaping of round spermatids into mature spermatozoa
Spermiogenesis is the final stage of spermatogenesis where round spermatids undergo structural changes. This includes the formation of the acrosome, condensation of the nucleus, and development of the flagellum.
Which hormone acts directly on Leydig cells to stimulate testosterone production?
- A Follicle-stimulating hormone
- B Luteinizing hormone
- C Gonadotropin-releasing hormone
- D Inhibin
Correct answer: Luteinizing hormone
Luteinizing hormone (LH) binds to receptors on the interstitial cells of Leydig. This triggers the signaling pathway that increases the conversion of cholesterol to testosterone.
During the menstrual cycle, the 'secretory phase' of the uterus corresponds to which ovarian phase?
- A Follicular phase
- B Ovulatory
- C Luteal phase
- D Menstrual phase
Correct answer: Luteal phase
The secretory phase occurs after ovulation, driven by progesterone from the corpus luteum. During this time, the endometrium becomes highly vascularized and glycogen-rich in preparation for a potential embryo.
What is the function of the acrosome in a mature sperm cell?
- A To generate the ATP that is required for flagellar motility
- B To carry and protect the haploid paternal genetic material
- C To store enzymes required to penetrate the zona pellucida
- D To anchor the sperm tail firmly to the Sertoli cell body
Correct answer: To store enzymes required to penetrate the zona pellucida
The acrosome is a cap-like vesicle filled with hydrolytic enzymes (like hyaluronidase). These enzymes are released during the acrosome reaction to digest the protective layers of the oocyte.
Which of the following is true regarding the number of functional gametes produced from one primary spermatocyte vs one primary oocyte?
- A Both produce four functional gametes
- B Primary spermatocyte produces four; primary oocyte produces one
- C Primary spermatocyte produces one; primary oocyte produces four
- D Both produce only one functional gamete
Correct answer: Primary spermatocyte produces four; primary oocyte produces one
Spermatogenesis results in four viable haploid sperm from one primary spermatocyte. Oogenesis involves unequal cytoplasmic division, resulting in one large functional ovum and three non-functional polar bodies.
At which stage of meiosis is the primary oocyte arrested from birth until puberty?
- A Anaphase I
- B Prophase I
- C Metaphase II
- D Prophase II
Correct answer: Prophase I
Oocytes begin meiosis during fetal development but are arrested in the diplotene stage of Prophase I. They remain in this state until they are recruited during a menstrual cycle after puberty.
Which hormone is responsible for maintaining the corpus luteum if fertilization and implantation occur?
- A Progesterone from the corpus luteum
- B Estrogen from follicles
- C Luteinizing hormone from the pituitary
- D Human chorionic gonadotropin
Correct answer: Human chorionic gonadotropin
hCG is produced by the syncytiotrophoblast of the developing embryo. It mimics LH to maintain the corpus luteum, ensuring continued progesterone production until the placenta can take over.
The 'blood-testis barrier' is primarily formed by which of the following?
- A Basement membrane of the seminiferous tubule
- B Tight junctions between Sertoli cells
- C Endothelial cells of the testicular capillaries
- D The tunica albuginea
Correct answer: Tight junctions between Sertoli cells
Tight junctions between adjacent Sertoli cells create a physical barrier. This prevents the blood-borne substances and immune cells from reaching the germ cells, which are genetically distinct and would be attacked as 'foreign'.
A rise in basal body temperature (approximately 0.5 degrees Celsius) is a clinical indicator that which event has occurred?
- A Menstruation
- B Ovulation
- C LH surge
- D Follicle recruitment
Correct answer: Ovulation
Progesterone has a thermogenic effect on the hypothalamus. Since progesterone levels rise sharply after ovulation (secreted by the corpus luteum), a sustained rise in temperature indicates ovulation has taken place.
What happens to the level of GnRH secretion when testosterone levels in the blood become excessively high?
- A GnRH secretion rises to compensate
- B GnRH secretion decreases due to negative feedback
- C GnRH secretion stays constant while LH selectively falls
- D GnRH secretion is permanently and irreversibly halted
Correct answer: GnRH secretion decreases due to negative feedback
Testosterone exerts negative feedback on both the hypothalamus (decreasing GnRH pulse frequency) and the anterior pituitary (decreasing LH/FSH sensitivity). This maintains homeostatic levels of androgens.