UPSC-CMS 2018 - Physiology PYQs Practice Questions

Q: Which one of the following is true regarding normal menstrual physiology?

Ovulation occurs after 12 hours of LH peak. ***Ovulation occurs after 12 hours of LH peak*** - Ovulation typically occurs approximately **10-12 hours after the luteinizing hormone (LH) peak** and about 34-36 hours after the initial rise in LH. This delay allows for the final maturation of the oocyte. - The **LH surge** is the crucial hormonal signal that triggers the ovulation process in the mature follicle. *Ovulation occurs after 48 hours of LH surge* - This statement is incorrect as **ovulation occurs much sooner** after the LH surge, typically within 34-36 hours from the onset of the surge, and 10-12 hours after its peak. - A 48-hour delay would mean the oocyte would likely be past its optimal viability for fertilization. *Oestradiol levels peak at 48 hours prior to ovulation* - **Estradiol levels peak approximately 24-36 hours before ovulation**, not 48 hours. This peak in estradiol is what triggers the surge in LH. - The timing of the estradiol peak is crucial in initiating the positive feedback loop that leads to the LH surge. *LH surge duration is typically 12-24 hours* - The **LH surge typically lasts for about 48 hours**, not 12-24 hours. A surge of this duration ensures sufficient time for the final maturation of the oocyte and the process of follicular rupture. - The prolonged nature of the LH surge is essential for the completion of meiosis I in the oocyte and the weakening of the follicular wall. [Practice more Physiology PYQs on OnCourse]

Q: 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:

3 and 4. ***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. [Practice more Physiology PYQs on OnCourse]

Question 1

Which one of the following is true regarding normal menstrual physiology?

Accepted Answer

Ovulation occurs after 12 hours of LH peak

Answer

Ovulation occurs after 48 hours of LH surge

Answer

Oestradiol levels peak at 48 hours prior to ovulation

Answer

LH surge duration is typically 12-24 hours

Question 2

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:

Accepted Answer

3 and 4

Answer

1, 3 and 4

Answer

2, 3 and 4

Answer

1, 2 and 3

Answer

1, 2 and 4

Answer

3 only

UPSC-CMS 2018 — Physiology