UPSC-CMS 2025 - Physiology PYQs Practice Questions

Q: Consider the following statements regarding respiratory function in old age: I. There is increasing ventilation-perfusion mismatch II. There is increased ventilatory response to hypoxia and hypercapnia III. There is a decline in maximum oxygen uptake leading to reduction in cardiorespiratory reserve IV. There is decline in the Forced Expiratory Volume to Forced Vital Capacity ratio (FEV1/FVC) by around 0.2% per year after the forties Which of the statements given above are correct?

I, III and IV. ***I, III and IV*** - With aging, there is a **loss of elastic recoil** in the lungs and a structural decrease in **alveolar surface area**, leading to increased **ventilation-perfusion (V/Q) mismatch** as gravity-dependent areas collapse. - The **maximum oxygen uptake (VO2 max)** declines with age due to reduced cardiac output and skeletal muscle mass, thus decreasing **cardiorespiratory reserve**. The **FEV1/FVC ratio** also decreases by approximately **0.2% per year** after age 40 because of reduced elastic recoil and increased airway collapsibility. *I, II and IV* - While statement I and IV are correct, statement II is incorrect because the **ventilatory response to hypoxia and hypercapnia** actually **decreases** with age. - Older adults have a blunted response to changes in oxygen and carbon dioxide levels, making them more susceptible to respiratory compromise. *II, III and IV* - Statement II is incorrect as the **ventilatory response to hypoxia and hypercapnia decreases** with age, not increases. - Statements III and IV accurately describe the decline in **maximum oxygen uptake** and the **FEV1/FVC ratio** with aging. *I, II and III* - Statement II is incorrect; the **ventilatory response to hypoxia and hypercapnia is diminished** in older adults. - Statements I and III correctly identify increased **ventilation-perfusion mismatch** and decreased **maximum oxygen uptake** as age-related changes in respiratory function. [Practice more Physiology PYQs on OnCourse]

Q: Resection of which part of intestine does not significantly affect fluid and electrolyte balance?

Distal jejunum. ***Distal jejunum*** - The distal jejunum has significant **adaptive capacity** to take over the absorptive functions of other parts of the small intestine if they are resected. - Its resection typically has the **least impact** on fluid and electrolyte balance compared to other segments of the intestine, as critical absorption of most nutrients, water, and electrolytes occurs more proximally or distally. *Ileum* - The ileum is crucial for the absorption of **vitamin B12** and **bile salts**; its resection can lead to **malabsorption** and severe diarrhea. - Loss of bile salt absorption can result in **fat malabsorption** and lead to fluid and electrolyte disturbances. *Proximal jejunum* - The proximal jejunum is the primary site for the absorption of most **nutrients** (carbohydrates, proteins, fats), **water**, and **electrolytes**. - Its resection can lead to significant **malnutrition** and severe fluid and electrolyte imbalances due to widespread malabsorption. *Colon* - The colon is responsible for the final absorption of **water** and **electrolytes**, compacting stool for elimination. - Its resection can severely impair the body's ability to conserve water and electrolytes, leading to **dehydration** and electrolyte disturbances. [Practice more Physiology PYQs on OnCourse]

Q: Good measure of systemic perfusion on ABG is:

Lactate and / or the base deficit. ***Lactate and / or the base deficit*** - **Lactate** is a direct indicator of **anaerobic metabolism**, which occurs when tissue oxygen supply is insufficient to meet demand, reflecting poor systemic perfusion. - **Base deficit** (or base excess) quantifies the overall metabolic acid-base status and is sensitive to changes in unmeasured anions like lactate, making it a good marker of **tissue hypoperfusion** and metabolic acidosis. *Bicarbonate* - While bicarbonate reflects the body's primary **buffer system**, changes in bicarbonate can be influenced by both respiratory and metabolic processes and thus are not as specific a marker for systemic perfusion as lactate or base deficit. - A low bicarbonate often indicates **metabolic acidosis**, but it doesn't pinpoint the cause as precisely as lactate, which directly reflects anaerobic metabolism. *PCO2* - **PCO2** primarily reflects the **ventilatory status** and respiratory component of acid-base balance. - While extreme changes can indirectly affect perfusion (e.g., hypercapnia leading to vasodilation), it is not a direct or reliable measure of **systemic tissue perfusion**. *pH* - **pH** indicates the overall acid-base balance but is a **composite measure** influenced by both respiratory (PCO2) and metabolic (bicarbonate, lactate) factors. - It does not specifically isolate **perfusion deficits** as clearly as lactate or base deficit, which directly reflect metabolic responses to tissue hypoxia. [Practice more Physiology PYQs on OnCourse]

Q: Which of the following are functions of the gall bladder? I. Reservoir for bile II. Production of bile III. Secretion of mucus IV. Concentration of bile Select the correct answer using the code given below :

I, III and IV. ***I, III and IV (Correct)*** - The gallbladder **stores bile** produced by the liver, acting as a reservoir (I) until it's needed for digestion. - It **concentrates bile** 5-20 fold (IV) by absorbing water and electrolytes through its epithelium. - The gallbladder epithelium **secretes mucin** (III), which forms a protective mucous layer. - The gallbladder does **NOT produce bile** (II) - this is exclusively a function of hepatocytes in the liver. *II, III and IV (Incorrect)* - This option incorrectly includes bile production (II), which is **not a function of the gallbladder**. - The **liver produces bile**; the gallbladder only stores and concentrates it. - While III and IV are correct functions, the inclusion of II makes this option wrong. *I, II and III (Incorrect)* - This option incorrectly states that the gallbladder produces bile (II), which is a **hepatic function**. - Additionally, it omits bile concentration (IV), which is one of the **primary functions** of the gallbladder. - Only I and III are correct in this combination. *I, II and IV (Incorrect)* - This option incorrectly includes bile production (II) as a gallbladder function. - The gallbladder's actual roles are **storage (I), concentration (IV), and mucus secretion (III)** - not bile production. [Practice more Physiology PYQs on OnCourse]

Question 1

Consider the following statements regarding respiratory function in old age:
I. There is increasing ventilation-perfusion mismatch
II. There is increased ventilatory response to hypoxia and hypercapnia
III. There is a decline in maximum oxygen uptake leading to reduction in cardiorespiratory reserve
IV. There is decline in the Forced Expiratory Volume to Forced Vital Capacity ratio (FEV1/FVC) by around 0.2% per year after the forties
Which of the statements given above are correct?

Accepted Answer

I, III and IV

Answer

I, II and IV

Answer

II, III and IV

Answer

I, II and III

Question 2

Resection of which part of intestine does not significantly affect fluid and electrolyte balance?

Accepted Answer

Distal jejunum

Answer

Ileum

Answer

Proximal jejunum

Answer

Colon

Question 3

Good measure of systemic perfusion on ABG is:

Accepted Answer

Lactate and / or the base deficit

Answer

Bicarbonate

Answer

PCO2

Answer

pH

Question 4

Which of the following are functions of the gall bladder?
I. Reservoir for bile
II. Production of bile
III. Secretion of mucus
IV. Concentration of bile

Select the correct answer using the code given below :

Accepted Answer

I, III and IV

Answer

II, III and IV

Answer

I, II and III

Answer

I, II and IV

UPSC-CMS 2025 — Physiology