Reproductive Physiology — MCQs
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The absence of fructose in the seminal fluid indicates a defect of
The respective hormones responsible for the breast milk secretion and ejection are, in that order:
Which of the following statements is/are correct regarding physiology of menstruation? 1. LH surge precedes ovulation 2. There are two peaks in serum estradiol levels, first in follicular and second in luteal phase 3. Serum progesterone has only one peak i.e., in luteal phase Select the correct answer using the code given below:
Where are antisperm antibodies usually present?
Which of the following statements regarding β-Human chorionic Gonadotropin are NOT correct? 1. It is a glycoprotein hormone. 2. Serum levels increase in pregnancy, germ cell tumors and gestational trophoblastic disease 3. Its levels are same in single and multiple pregnancy 4. Both alpha and beta subunits are unique and not shared with other hormones Select the correct answer using the codes given below:
The amount of iron lost per 28 day cycle in menstruating women is
A couple presented to OPD with complaint of inability to conceive for the last 3 years. Husband was advised semen analysis. What is the WHO criterion for minimum sperm count per ml in normal semen?
Oxytocin is not responsible for:
Which one of the following is true about Basal body temperature? 1. Shows a biphasic pattern during menstrual cycle 2. Rises by 0.3-0.5°C after ovulation due to progesterone 3. Can be used to confirm that ovulation has occurred 4. Remains constant throughout the menstrual cycle Select the correct answer using the code given below:
Which of the following prevents polyspermy?
Reproductive Physiology Indian Medical PG Practice Questions and MCQs
Question 351: The absence of fructose in the seminal fluid indicates a defect of
- A. Seminal vesicles (Correct Answer)
- B. Leydig cells
- C. Hypothalamic-pituitary axis
- D. Testicular tubular epithelium
Explanation: ***Seminal vesicles*** - The **seminal vesicles** are responsible for producing and secreting a significant portion of the seminal fluid, including **fructose**. - **Fructose** serves as the primary **energy source** for sperm motility; its absence indicates a defect in these glands. *Leydig cells* - **Leydig cells** are located in the testes and primarily produce **testosterone**, which is crucial for male sexual development and spermatogenesis. - While important for sperm production indirectly, they do not directly contribute to the **fructose content** of seminal fluid. *Hypothalamic-pituitary axis* - The **hypothalamic-pituitary axis** regulates testicular function by releasing hormones like **GnRH**, **LH**, and **FSH**, which control testosterone production and spermatogenesis. - A defect here would primarily affect hormone levels and sperm production, not directly the **fructose secretion** from seminal vesicles. *Testicular tubular epithelium* - The **testicular tubular epithelium** (Sertoli cells and germ cells) is involved in **spermatogenesis**, the process of sperm formation. - While essential for producing mature sperm, it does not contribute to the production or secretion of **fructose** into the seminal fluid.
Question 352: The respective hormones responsible for the breast milk secretion and ejection are, in that order:
- A. Prolactin and Oxytocin (Correct Answer)
- B. Oestrogen and Prolactin
- C. Oxytocin and Prolactin
- D. Prolactin and Oestrogen
Explanation: ***Prolactin and Oxytocin*** - **Prolactin** is the primary hormone responsible for the **synthesis and secretion of milk** from the mammary glands. - **Oxytocin** is responsible for the **milk ejection reflex**, causing contraction of myoepithelial cells around the alveoli and ducts to release milk. *Oestrogen and Prolactin* - **Oestrogen** primarily plays a crucial role in the **development of the mammary glands** during puberty and pregnancy, but it inhibits milk secretion. - While **prolactin** is involved in milk secretion, oestrogen's role is not milk ejection. *Oxytocin and Prolactin* - This option reverses the order of the hormones' functions; **oxytocin** is for ejection, not secretion first. - **Prolactin** is for milk secretion, not ejection. *Prolactin and Oestrogen* - **Prolactin** is responsible for milk secretion. - **Oestrogen** *inhibits* milk secretion and is not involved in milk ejection.
Question 353: Which of the following statements is/are correct regarding physiology of menstruation? 1. LH surge precedes ovulation 2. There are two peaks in serum estradiol levels, first in follicular and second in luteal phase 3. Serum progesterone has only one peak i.e., in luteal phase Select the correct answer using the code given below:
- A. 1, 2 and 3 (Correct Answer)
- B. 2 and 3 only
- C. 1 and 2 only
- D. 1 only
Explanation: ***1, 2 and 3*** - All statements accurately describe key hormonal events during the menstrual cycle. The **LH surge** is indeed the trigger for ovulation, with **estradiol** exhibiting a biphasic pattern, and **progesterone** peaking in the luteal phase. - Understanding the precise timing and interaction of these hormonal events is fundamental to comprehending the entire **physiological process of menstruation**, including follicular development, ovulation, and preparation for potential pregnancy. *2 and 3 only* - This option is incorrect because it omits statement 1, which correctly identifies that the **LH surge precedes ovulation**, a crucial event for ovarian follicle rupture and oocyte release. - The **LH surge** is a direct consequence of rising estrogen levels and is essential for triggering the final maturation of the oocyte and its release from the Graafian follicle. *1 and 2 only* - This option is incorrect because it omits statement 3, which correctly notes that **serum progesterone has only one peak in the luteal phase**, produced by the corpus luteum after ovulation. - The rise in **progesterone** in the luteal phase is vital for preparing the uterine endometrium for implantation and maintaining a potential pregnancy. *1 only* - This option is incorrect as it only acknowledges the **LH surge preceding ovulation** but fails to include the accurate descriptions of the **biphasic estradiol peaks** and the **single progesterone peak** in the luteal phase, both of which are fundamental aspects of the menstrual cycle. - A comprehensive understanding of menstrual physiology requires recognizing the interplay of all these hormonal dynamics throughout the cycle.
Question 354: Where are antisperm antibodies usually present?
- A. Vagina
- B. Cervix (Correct Answer)
- C. Fallopian tube
- D. Uterus
Explanation: ***Cervix*** - Antisperm antibodies are commonly found in the **cervical mucus**, where they can immobilize or agglutinate sperm, preventing their passage into the uterus. - The cervix acts as a key immunological barrier, and its secretions can contain antibodies that interfere with **sperm motility and viability**. *Vagina* - While some antibodies may be present, the **acidic environment** of the vagina is generally hostile to sperm, and it is not the primary site for antisperm antibody action in infertility. - The vagina's role is more about initial sperm reception rather than a concentrated immunological barrier against sperm movement. *Fallopian tube* - The fallopian tubes are primarily involved in **sperm capacitation**, fertilization, and early embryo transport. - Although immune cells exist, it is not the most common location for significant levels of antisperm antibodies to cause issues with sperm transport into the uterus. *Uterus* - The uterus is mainly a site for sperm transport to the fallopian tubes and implantation of the embryo. - While immune responses can occur, the **cervix** is the more critical location for antisperm antibody presence causing clinical infertility by blocking sperm entry.
Question 355: Which of the following statements regarding β-Human chorionic Gonadotropin are NOT correct? 1. It is a glycoprotein hormone. 2. Serum levels increase in pregnancy, germ cell tumors and gestational trophoblastic disease 3. Its levels are same in single and multiple pregnancy 4. Both alpha and beta subunits are unique and not shared with other hormones Select the correct answer using the codes given below:
- A. 1, 3 and 4
- B. 2, 3 and 4
- C. 1, 2 and 3
- D. 1, 2 and 4
- E. 3 only
- F. 3 and 4 (Correct Answer)
Explanation: ***3 and 4*** * Statements 3 and 4 are both **incorrect** regarding β-hCG. * **Statement 3 is incorrect:** β-hCG levels are **significantly higher** in multiple pregnancies compared to singleton pregnancies. Twin pregnancies typically show 30-50% higher β-hCG levels. * **Statement 4 is incorrect:** β-hCG shares a **common alpha subunit** with FSH, LH, and TSH. Only the **beta subunit is unique** and provides diagnostic specificity. This is a key concept in understanding glycoprotein hormone structure. *1, 3 and 4* * This option incorrectly includes statement 1 as incorrect. * Statement 1 is **correct** - β-hCG is a well-established glycoprotein hormone with carbohydrate moieties attached to a protein core. * While statements 3 and 4 are indeed incorrect, including the correct statement 1 makes this option wrong. *2, 3 and 4* * This option incorrectly includes statement 2 as incorrect. * Statement 2 is **correct** - serum β-hCG levels are markedly elevated in normal pregnancy, germ cell tumors (seminomas, choriocarcinomas), and gestational trophoblastic disease (molar pregnancy). *1, 2 and 3* * This option incorrectly identifies statements 1 and 2 as incorrect when both are correct. * It also omits statement 4, which is incorrect regarding the subunit structure of β-hCG.
Question 356: The amount of iron lost per 28 day cycle in menstruating women is
- A. 8.5 mg
- B. 15.5 mg (Correct Answer)
- C. 12.5 mg
- D. 5.5 mg
Explanation: ***15.5 mg*** - The typical **iron loss** during a 28-day menstrual cycle in menstruating women is approximately **15-28 mg**, with an average of about **15.5 mg**. - This calculation is based on average menstrual blood loss of **30-40 mL per cycle** and iron content of approximately **0.5 mg per mL of blood**. - This physiological iron loss explains why menstruating women have **higher iron requirements** (18 mg/day) compared to men (8 mg/day). - If dietary iron intake is insufficient to compensate for this loss, **iron deficiency anemia** can develop over time. *5.5 mg* - This value significantly **underestimates** the actual iron loss during menstruation. - Such a low amount would not explain the increased iron requirements in menstruating women. - This does not align with measured menstrual blood loss volumes. *8.5 mg* - This value is still **lower than the typical physiological range** of iron loss during menstruation. - While closer than 5.5 mg, it underestimates the actual iron depletion that occurs. *12.5 mg* - This value is **within the lower range** but still below the commonly accepted average. - While individual variations exist, standard teaching emphasizes higher values (15-28 mg range).
Question 357: A couple presented to OPD with complaint of inability to conceive for the last 3 years. Husband was advised semen analysis. What is the WHO criterion for minimum sperm count per ml in normal semen?
- A. 30 million
- B. 40 million
- C. 15 million (Correct Answer)
- D. 10 million
Explanation: ***15 million*** - The **WHO 2010 criteria** for normal semen analysis specifies a lower reference limit for sperm concentration as **15 million spermatozoa per mL**. - This count is considered the minimum threshold for **normal fertility potential** according to current international guidelines. *30 million* - While a higher sperm count, **30 million** is not the minimum threshold set by the WHO for normal semen analysis. - A count of 30 million would be considered well within the normal range, but the question specifically asks for the *minimum* criterion. *40 million* - **40 million** is significantly above the minimum sperm concentration required for normal fertility as per WHO guidelines. - This higher count would indicate robust spermatogenesis but is not the lower limit for defining normalcy. *10 million* - A sperm count of **10 million spermatozoa per mL** falls below the **WHO 2010 reference range** for normal sperm concentration. - This value would likely be considered **oligozoospermia** and could indicate reduced fertility potential.
Question 358: Oxytocin is not responsible for:
- A. Uterine involution
- B. After pains
- C. Milk ejection
- D. Milk production (Correct Answer)
Explanation: ***Milk production*** - **Oxytocin** is primarily responsible for the **ejection of milk** from the mammary glands, not its production. - **Prolactin** is the hormone chiefly responsible for **milk synthesis** or production. *Uterine involution* - **Oxytocin** plays a crucial role in **uterine contractions** postpartum, which helps the uterus return to its normal size (involution). - These contractions compress blood vessels, reducing **postpartum hemorrhage**. *After pains* - The contractions stimulated by **oxytocin** after childbirth, essential for uterine involution, are often perceived as **'after pains'**. - These pains are more pronounced in **multiparas** and breastfeeding women due to vigorous oxytocin release. *Milk ejection* - **Oxytocin** causes the contraction of **myoepithelial cells** surrounding the alveoli in the mammary glands. - This contraction leads to the **'let-down reflex,'** forcing milk into the ducts and outward through the nipple.
Question 359: Which one of the following is true about Basal body temperature? 1. Shows a biphasic pattern during menstrual cycle 2. Rises by 0.3-0.5°C after ovulation due to progesterone 3. Can be used to confirm that ovulation has occurred 4. Remains constant throughout the menstrual cycle Select the correct answer using the code given below:
- A. 1, 2 and 3 (Correct Answer)
- B. 2, 3 and 4
- C. 1, 3 and 4
- D. All of the above
Explanation: ***1, 2 and 3*** - Basal Body Temperature (BBT) exhibits a **biphasic pattern** during the menstrual cycle, with a lower temperature in the follicular phase (before ovulation) and a higher temperature in the luteal phase (after ovulation). - The rise in BBT of **0.3-0.5°C** following ovulation is a direct result of increased **progesterone** secretion from the corpus luteum, which has thermogenic properties. - BBT is a **retrospective indicator** that **confirms ovulation has occurred** by showing the sustained temperature elevation, making it useful for tracking ovulation patterns over time. *2, 3 and 4* - This option is incorrect because BBT does **not remain constant** throughout the menstrual cycle; it shows a characteristic **biphasic pattern** with lower temperatures before ovulation and higher temperatures after. *1, 3 and 4* - This option is incorrect because statement 4 is false - BBT does **not remain constant** but rather demonstrates a **biphasic shift** with a temperature rise after ovulation. *All of the above* - This option is incorrect because statement 4 is false - BBT shows a **biphasic pattern**, not a constant temperature throughout the cycle.
Question 360: Which of the following prevents polyspermy?
- A. Acrosome reaction
- B. Cortical reaction (Correct Answer)
- C. Zona reaction
- D. Capacitation
Explanation: ***Cortical reaction*** - The **cortical reaction** is the primary mechanism that prevents **polyspermy** following sperm-oocyte fusion. - Upon fusion, **cortical granules** in the oocyte cytoplasm release their contents (including proteases and peroxidases) into the **perivitelline space**. - These enzymes modify the **zona pellucida** proteins, making it impermeable to additional sperm - this modification is called the **zona reaction**. - The cortical reaction represents both the **fast block** (depolarization of oocyte membrane) and **slow block** (zona pellucida hardening) to polyspermy. *Zona reaction* - The **zona reaction** is the biochemical and structural change that occurs in the zona pellucida as a **result** of the cortical reaction. - It involves hardening and altered permeability of the zona pellucida, making it resistant to sperm penetration. - While this is the ultimate barrier to polyspermy, it is a **consequence** rather than the active mechanism - the cortical reaction is the causative event. *Acrosome reaction* - The **acrosome reaction** is essential for fertilization, allowing sperm to penetrate the zona pellucida by releasing hydrolytic enzymes. - It **facilitates** sperm entry rather than preventing additional sperm from binding. - This reaction must occur for the first sperm to fertilize the egg but plays no role in preventing polyspermy. *Capacitation* - **Capacitation** is the physiological maturation of sperm in the female reproductive tract. - It enables sperm to undergo the acrosome reaction and achieve fertilization competence. - It is a preparatory process and has no role in preventing polyspermy.
Practice by Chapter
Male Reproductive Physiology
Practice Questions
Spermatogenesis and Sperm Function
Practice Questions
Female Reproductive Physiology
Practice Questions
Menstrual Cycle
Practice Questions
Ovulation and Fertilization
Practice Questions
Physiology of Pregnancy
Practice Questions
Parturition
Practice Questions
Lactation
Practice Questions
Sexual Differentiation and Development
Practice Questions
Reproductive Aging
Practice Questions
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