UPSC-CMS 2013 - Physiology PYQs Practice Questions

Q: Pregnancy is characterized by the following physiological changes except :

Decreased glomerular filtration rate. ***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 more Physiology PYQs on OnCourse]

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

Sodium chloride. ***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. [Practice more Physiology PYQs on OnCourse]

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

Umbilical artery carries oxygenated blood to the fetus. ***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. [Practice more Physiology PYQs on OnCourse]

Q: Which of the following is X-linked dominant trait?

Vitamin D resistant rickets. ***Vitamin D resistant rickets*** - This condition is characterized by **impaired kidney reabsorption of phosphate** and **defective bone mineralization**, leading to rickets, and it is inherited in an **X-linked dominant pattern**. - In X-linked dominant traits, an affected father will pass the trait to **all his daughters**, but none of his sons. An affected mother has a 50% chance of passing the trait to **each child**, regardless of sex. *Colour blindness* - **Color blindness** is an **X-linked recessive** disorder, meaning it is more common in males. - Affected individuals have **difficulty distinguishing certain colors**, usually red and green. *Haemophilia-A* - **Hemophilia A** is an **X-linked recessive** disorder caused by a deficiency in **Factor VIII**, leading to uncontrolled bleeding. - Males are predominantly affected, while females are typically carriers. *Duchenne muscular dystrophy* - **Duchenne muscular dystrophy** is an **X-linked recessive** disorder characterized by progressive muscle degeneration and weakness due to a mutation in the **dystrophin gene**. - It primarily affects males, with symptoms often appearing in early childhood. [Practice more Physiology PYQs on OnCourse]

Question 1

Non-cardiac causes of raised central venous pressure include all of the following except:

Accepted Answer

Hyper-volemia

Answer

Abdominal compartment syndrome

Answer

Positive pressure ventilation

Answer

Tension pneumothorax

Question 2

Pregnancy is characterized by the following physiological changes except :

Accepted Answer

Decreased glomerular filtration rate

Answer

Dilatation of ureters

Answer

Delayed gastric emptying time

Answer

Increased tidal volume

Question 3

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

Accepted Answer

Sodium chloride

Answer

Sodium bicarbonate

Answer

Potassium chloride

Answer

Potassium bicarbonate

Question 4

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

Accepted Answer

Umbilical artery carries oxygenated blood to the fetus

Answer

Umbilical artery carries deoxygenated fetal blood to the placenta

Answer

Two umbilical arteries and one umbilical vein traverse through the fetus and placenta

Answer

Umbilical vein carries oxygenated blood to the fetus

Question 5

Which of the following is X-linked dominant trait?

Accepted Answer

Vitamin D resistant rickets

Answer

Colour blindness

Answer

Haemophilia-A

Answer

Duchenne muscular dystrophy

UPSC-CMS 2013 — Physiology