Reproductive Physiology — MCQs

Which of the following are advantages of state of haemodilution during pregnancy? 1. Optimum gaseous exchange between maternal and foetal circulation due to decreased blood viscosity 2. Protection against adverse effect of blood loss during delivery 3. Increased oxygen carrying capacity of blood Select the correct answer using the code given below.

Q345

Which one of the following statements is correct regarding foetal physiology?

Q346

In hyperemesis gravidarum, Wernicke's encephalopathy is seen due to the deficiency of

Q347

After how many hours of LH surge does the ovulation occur?

Q348

Which one of the following statements is not correct about fetal circulation?

Q349

The ferning of cervical mucus is due to the high concentration of :

Q350

Pregnancy is characterized by the following physiological changes except :

Reproductive Physiology Indian Medical PG Practice Questions and MCQs

Question 341: Identify the inheritance pattern shown below.

A. Y linked recessive
B. X linked recessive (Correct Answer)
C. X linked dominant
D. Y linked dominant

Explanation: ***X linked recessive*** - The pattern shows that mainly **males are affected**, and the trait skips generations (e.g., individual I-1 is unaffected, but his children are affected). - Affected fathers (like II-3) do not pass the trait to their sons, but their daughters are carriers and can pass it on to their sons (like IV-1). *Y linked recessive* - In Y-linked inheritance, only **males would be affected**, and all sons of an affected father would inherit the trait. - This pedigree shows unaffected fathers having affected sons, and not all sons of affected males are affected directly. *X linked dominant* - In X-linked dominant inheritance, affected fathers pass the trait to **all their daughters**, and at least one parent would be affected in each generation. - This pedigree shows skipping of generations and affected individuals being born to unaffected parents (e.g., II-3 and III-5). *Y linked dominant* - Y-linked inheritance, whether dominant or recessive, would only affect **males** and would be directly passed from father to all sons. - The pedigree shows unaffected parents having affected offspring (e.g., I-1 and I-2 produced II-3), which rules out Y-linked inheritance.

Question 342: Carbohydrate metabolism in normal pregnancy shows :

A. Fasting hypoglycaemia (Correct Answer)
B. Decreased plasma glucagon levels
C. Postprandial hypoglycaemia
D. Increased sensitivity of insulin receptors in mother

Explanation: ***Fasting hypoglycaemia*** - Due to the **fetus continuously drawing glucose** from the mother's circulation, the mother's glucose levels can fall between meals or during prolonged fasting. - This is exacerbated by the **increased insulin secretion** in early pregnancy and **increased peripheral glucose utilization**. *Decreased plasma glucagon levels* - Plasma **glucagon levels are generally increased** or unchanged in normal pregnancy to counteract the tendency towards hypoglycemia. - Glucagon helps **mobilize glucose from liver stores** to maintain maternal blood glucose levels. *Postprandial hypoglycaemia* - Pregnancy is typically characterized by **postprandial hyperglycemia** due to increased insulin resistance later in pregnancy and a slower insulin response. - The delayed insulin response means that glucose levels can rise higher after a meal before insulin restores them to normal. *Increased sensitivity of insulin receptors in mother* - In normal pregnancy, especially in the **second and third trimesters**, there is a physiologic **decrease in maternal insulin sensitivity**. - This **insulin resistance**, mediated by placental hormones, ensures adequate glucose supply to the fetus.

Question 343: Onset of labour is initiated by which of the following?

A. Increased level of progesterone immediately before labour
B. Uterine distension
C. Increased synthesis of myometrial receptors for oxytocin due to effect of oestrogen (Correct Answer)
D. Increased CRH and ACTH from foetal hypothalamic-pituitary-adrenal axis

Explanation: ***Increased synthesis of myometrial receptors for oxytocin due to effect of oestrogen*** - **Estrogen** plays a crucial role in initiating labor by increasing the number of **oxytocin receptors** in the myometrium, making the uterus more sensitive to oxytocin's contractile effects. - **Oxytocin** then stimulates strong, coordinated uterine contractions essential for cervical dilation and expulsion of the fetus. *Increased level of progesterone immediately before labour* - During pregnancy, **progesterone** maintains uterine quiescence and prevents premature contractions. - The withdrawal or decrease in the inhibitory effect of progesterone, not an increase, is thought to be involved in the onset of labor. *Uterine distension* - While **uterine distension** contributes to uterine irritability and can trigger some contractions, it is not the primary initiator of true labor. - It is a physical factor that complements hormonal changes but doesn't independently start the complex cascade of labor. *Increased CRH and ACTH from foetal hypothalamic-pituitary-adrenal axis* - An increase in **fetal corticotropin-releasing hormone (CRH)** and **adrenocorticotropic hormone (ACTH)** leads to increased fetal cortisol. - Fetal cortisol then signals the placenta to produce more estrogen and less progesterone, thereby indirectly contributing to labor initiation, but it's not the direct trigger for contractions.

Question 344: Which of the following are advantages of state of haemodilution during pregnancy? 1. Optimum gaseous exchange between maternal and foetal circulation due to decreased blood viscosity 2. Protection against adverse effect of blood loss during delivery 3. Increased oxygen carrying capacity of blood Select the correct answer using the code given below.

A. 1, 2 and 3
B. 1 and 3 only
C. 2 and 3 only
D. 1 and 2 only (Correct Answer)

Explanation: ***1 and 2 only*** - **Haemodilution** during pregnancy, characterized by a disproportionate increase in plasma volume relative to red blood cell mass, leads to decreased blood **viscosity**. - A lower blood viscosity facilitates more efficient **gaseous exchange** (oxygen and carbon dioxide) between the maternal and fetal circulations at the placenta, and also offers a degree of protection against the effects of **blood loss during delivery** by maintaining circulating volume. *1, 2 and 3* - While haemodilution promotes efficient gaseous exchange and protects against blood loss, it does **not increase the oxygen carrying capacity** of the blood. - In fact, the relative decrease in red blood cell concentration leads to physiological anemia of pregnancy, which reduces the oxygen-carrying capacity (though total oxygen delivery may be maintained by increased cardiac output). *2 and 3 only* - This option correctly identifies protection against blood loss but incorrectly states an **increased oxygen carrying capacity**. - The primary mechanism for improved oxygen delivery is enhanced blood flow due to reduced viscosity and increased cardiac output, not an increased concentration of oxygen carriers. *1 and 3 only* - This option correctly identifies improved gaseous exchange but incorrectly suggests an **increased oxygen carrying capacity**. - Protection against blood loss is a significant benefit of pregnancy-induced haemodilution, which is overlooked in this choice.

Question 345: Which one of the following statements is correct regarding foetal physiology?

A. Foetal pancreas secretes insulin as early as 20 weeks.
B. Haematopoiesis is demonstrated first in the yolk sac by 14th day. (Correct Answer)
C. Meconium appears at 16 weeks.
D. Breathing movements are identified at 26 weeks.

Explanation: **Haematopoiesis is demonstrated first in the yolk sac by 14th day.** - **Hematopoiesis** (blood cell formation) begins as early as the 14th day of gestation within the **yolk sac**, which is the primary site for this process during the initial weeks. - This early development is crucial for meeting the oxygen and nutrient demands of the rapidly growing embryo. *Foetal pancreas secretes insulin as early as 20 weeks.* - The fetal pancreas begins to secrete some insulin as early as **10-12 weeks** of gestation, although significant secretion and functional maturity develop later. - By **20 weeks**, the fetal pancreas is well-differentiated, but insulin production starts earlier than this specific time point. *Meconium appears at 16 weeks.* - **Meconium** typically begins to form around **10-14 weeks** of gestation, but its appearance at the anus (often indicating a bowel movement) is usually noted later in the third trimester or at birth. - The formation at 16 weeks is too late for its initial appearance and too early for its common clinical observation. *Breathing movements are identified at 26 weeks.* - Fetal **breathing movements** can be identified much earlier, often by **18-20 weeks** of gestation using ultrasound. - These movements are intermittent and contribute to lung development, although they do not involve air exchange.

Question 346: In hyperemesis gravidarum, Wernicke's encephalopathy is seen due to the deficiency of

A. vitamin B6
B. vitamin B12
C. vitamin B1 (Correct Answer)
D. vitamin B9

Explanation: ***vitamin B1*** - **Wernicke's encephalopathy** is directly caused by a severe deficiency of **thiamine (vitamin B1)**. - In **hyperemesis gravidarum**, persistent vomiting leads to inadequate intake and absorption of this vital vitamin. *vitamin B6* - Deficiency of **vitamin B6 (pyridoxine)** can cause peripheral neuropathy, glossitis, and dermatitis. - While important for many metabolic processes, its deficiency is not directly linked to Wernicke's encephalopathy. *vitamin B12* - **Vitamin B12 (cobalamin)** deficiency primarily results in megaloblastic anemia and subacute combined degeneration of the spinal cord. - It does not cause the specific neurological triad of Wernicke's encephalopathy. *vitamin B9* - Deficiency of **vitamin B9 (folate)** leads to megaloblastic anemia and is crucial for neural tube development. - It is not associated with the pathogenesis of Wernicke's encephalopathy.

Question 347: After how many hours of LH surge does the ovulation occur?

A. 24-48 hours
B. 12-24 hours
C. 12-36 hours
D. 24-36 hours (Correct Answer)

Explanation: ***24-36 hours*** - The **luteinizing hormone (LH) surge** triggers the final maturation of the oocyte and rupture of the dominant follicle. - Ovulation typically occurs **24-36 hours after the onset of the LH surge**, or approximately **10-18 hours after the LH peak**. - This is the **standard timeframe** taught in reproductive physiology and corresponds to the physiological cascade required for follicular rupture. *12-24 hours* - This timeframe is **too early** for ovulation to occur after the LH surge onset. - While some follicular changes begin during this period, the complete maturation and rupture process typically requires more time. - This might represent the interval from LH peak in some cases, but not from surge onset. *12-36 hours* - This range is **too broad** and includes both early (12h) and appropriate (24-36h) timeframes. - While the upper range is correct, the lower bound extends into a period when ovulation has typically not yet occurred. - Less precise than the 24-36 hour window. *24-48 hours* - While ovulation can occasionally occur up to 48 hours post-surge, this is **less common**. - The upper limit (48h) extends beyond the typical ovulation window. - Most ovulations are completed by 36 hours after the LH surge onset.

Question 348: Which one of the following statements is not correct about fetal circulation?

A. Umbilical artery carries deoxygenated fetal blood to the placenta
B. Two umbilical arteries and one umbilical vein traverse through the fetus and placenta
C. Umbilical vein carries oxygenated blood to the fetus
D. Umbilical artery carries oxygenated blood to the fetus (Correct Answer)

Explanation: ***Umbilical artery carries oxygenated blood to the fetus*** - This statement is incorrect because the **umbilical arteries** carry **deoxygenated blood** and waste products away from the fetus to the placenta. - Oxygenated blood is carried *to* the fetus by the **umbilical vein**. *Umbilical artery carries deoxygenated fetal blood to the placenta* - This statement is correct. The **umbilical arteries** are responsible for transporting **deoxygenated blood** and metabolic waste products from the fetal circulation back to the placenta for exchange with the maternal blood. - This is a key component of the fetoplacental circulation. *Two umbilical arteries and one umbilical vein traverse through the fetus and placenta* - This statement is correct. The **umbilical cord** typically contains **two umbilical arteries** and one **umbilical vein**. - This arrangement facilitates efficient nutrient and gas exchange between the mother and fetus. *Umbilical vein carries oxygenated blood to the fetus* - This statement is correct. The **umbilical vein** carries **oxygenated blood** rich in nutrients from the placenta to the fetus. - This is the main conduit for essential substances required for fetal growth and development.

Question 349: The ferning of cervical mucus is due to the high concentration of :

A. Sodium chloride (Correct Answer)
B. Sodium bicarbonate
C. Potassium chloride
D. Potassium bicarbonate

Explanation: ***Sodium chloride*** - The characteristic **ferning pattern** observed in cervical mucus is primarily due to the crystallization of **sodium chloride** under the influence of estrogen. - This crystallization occurs as the mucus dries on a slide, forming a fern-like pattern that indicates high estrogen levels and often signifies the periovulatory period. *Sodium bicarbonate* - While present in bodily fluids, **sodium bicarbonate** does not directly contribute to the characteristic fern-like crystallization seen in cervical mucus. - Its primary role is buffering, maintaining pH balance, rather than forming crystal patterns. *Potassium chloride* - Although potassium ions are present in cervical secretions, **potassium chloride** does not specifically form the classic fenestrated pattern observed in ferning. - The unique crystallization properties of sodium chloride distinguish it from other salts in this context. *Potassium bicarbonate* - Similar to sodium bicarbonate, **potassium bicarbonate** does not contribute to the fern phenomenon of cervical mucus. - It plays a role in pH regulation but not in the distinct crystallization pattern associated with estrogen and fertility.

Question 350: Pregnancy is characterized by the following physiological changes except :

A. Dilatation of ureters
B. Delayed gastric emptying time
C. Decreased glomerular filtration rate (Correct Answer)
D. Increased tidal volume

Explanation: ***Decreased glomerular filtration rate*** - During **pregnancy**, there is a significant **increase in glomerular filtration rate (GFR)**, typically by 30-50%, due to increased renal blood flow and vasodilation. - A decreased GFR would be an abnormal finding, indicating renal dysfunction, not a normal physiological change of pregnancy. *Dilatation of ureters* - **Physiological hydronephrosis** and **utereral dilation** are common in pregnancy, primarily due to the relaxed smooth muscle effects of **progesterone** and mechanical compression by the gravid uterus. - This dilation occurs as early as the first trimester and can persist until after delivery. *Delayed gastric emptying time* - **Progesterone** acts as a smooth muscle relaxant, leading to decreased gastrointestinal motility and a **delayed gastric emptying time** during pregnancy. - This can contribute to common pregnancy symptoms like **nausea, vomiting**, and **heartburn**. *Increased tidal volume* - **Tidal volume (TV)** increases during pregnancy, primarily driven by hormonal changes, specifically **progesterone**. - This increase in TV leads to a greater minute ventilation, helping to meet the increased oxygen demands of both the mother and the fetus.

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

Want unlimited practice?

Get full access to all questions, explanations, and performance tracking.

Start For Free