Renal Physiology Indian Medical PG Practice Questions and MCQs
Practice Indian Medical PG questions for Renal Physiology. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Renal Physiology Indian Medical PG Question 1: Which carrier pump is responsible for transporting solutes in the thick ascending limb of the loop of Henle?
- A. NaCl cotransporter
- B. Na+-H+ exchanger
- C. Na+-K+ exchanger
- D. Sodium-potassium-chloride cotransporter (Correct Answer)
Renal Physiology Explanation: * **Sodium-potassium-chloride cotransporter.**
* This transporter, specifically the **Na+-K+-2Cl- cotransporter (NKCC2)**, is highly expressed in the apical membrane of the thick ascending limb.
* It actively reabsorbs **sodium, potassium, and chloride ions** from the filtrate, contributing significantly to the medullary interstitial osmotic gradient.
* *NaCl- cotransporter*
* The **NaCl cotransporter (NCC)** is primarily found in the **distal convoluted tubule**, not the thick ascending limb.
* It reabsorbs sodium and chloride in a 1:1 ratio and is the target of thiazide diuretics.
* *Na+-H+ exchanger*
* The **Na+-H+ exchanger (NHE3)** is predominantly located in the **proximal tubule** where it plays a crucial role in bicarbonate reabsorption and acid-base balance.
* While some NHE activity exists in other nephron segments, it is not the primary carrier in the thick ascending limb.
* *Na+-K+ exchanger*
* The **Na+-K+ exchanger** or **Na+/K+-ATPase pump** is located on the basolateral membrane of most renal tubular cells, including the thick ascending limb.
* Its main function is to maintain the electrochemical gradient by pumping **sodium out of the cell** and potassium into the cell, which indirectly drives other transporters but is not the apical cotransporter responsible for initial solute reabsorption in the thick ascending limb.
Renal Physiology Indian Medical PG Question 2: A healthy 22-year-old female medical student with normal kidneys decreases her sodium intake by 50% for a period of 2 months. Which of the following parameters is expected to increase in response to the reduction in sodium intake?
- A. Atrial natriuretic peptide release
- B. Extracellular fluid volume
- C. Arterial pressure
- D. Renin release (Correct Answer)
Renal Physiology Explanation: ***Renin release***
- A reduction in **sodium intake** leads to decreased extracellular fluid volume and **reduced renal perfusion pressure**, which stimulates **renin release** from the juxtaglomerular cells.
- Renin initiates the **renin-angiotensin-aldosterone system (RAAS)**, leading to **angiotensin II** formation and increased **aldosterone** secretion, aimed at sodium and water retention.
*Atrial natriuretic peptide release*
- **Atrial natriuretic peptide (ANP)** release is stimulated by **atrial stretch** due to increased blood volume and pressure, which would decrease with reduced sodium intake.
- Therefore, ANP release would likely **decrease** or remain unchanged, not increase, in response to chronic sodium restriction.
*Extracellular fluid volume*
- A decrease in sodium intake directly leads to a **reduction in total body sodium**, which is the primary determinant of **extracellular fluid volume**.
- The body attempts to maintain fluid balance, but chronic sodium restriction will ultimately lead to a **decrease** in extracellular fluid volume as the kidneys excrete less water to match the lower sodium intake.
*Arterial pressure*
- Reduced sodium intake typically leads to a **decrease in extracellular fluid volume** and **cardiac output**, which in turn causes a **reduction in arterial blood pressure**.
- The activation of the RAAS aims to mitigate this drop but usually does not fully compensate to increase pressure above baseline in this scenario.
Renal Physiology Indian Medical PG Question 3: Which of the following statements are correct regarding renal cell carcinoma?
1. It arises from the epithelium of the proximal convoluted tubule.
2. It has a female preponderance.
3. Major subtypes are clear cell, papillary and chromophobe.
4. Surgery is the mainstay of treatment for organ-confined disease. Select the answer using the code given below.
- A. 1, 2 and 3
- B. 1, 3 and 4 (Correct Answer)
- C. 1, 2 and 4
- D. 2, 3 and 4
Renal Physiology Explanation: ***1, 3 and 4***
- **Renal cell carcinoma (RCC)** most commonly arises from the **epithelium of the proximal convoluted tubule**, particularly the clear cell subtype [1]. This makes statement 1 correct.
- The major subtypes of RCC are indeed **clear cell, papillary, and chromophobe carcinomas**, accounting for the vast majority of cases [1]. This validates statement 3.
- For **organ-confined renal cell carcinoma**, **surgical resection (nephrectomy)** remains the primary and most effective treatment modality, making statement 4 correct. [1]
*1, 2 and 3*
- This option incorrectly includes statement 2, which claims a female preponderance for RCC. **Renal cell carcinoma is more common in males** than females, not the reverse [1].
- While statements 1 and 3 are correct regarding the origin and major subtypes of RCC, the inclusion of an incorrect epidemiological fact makes this option wrong.
*1, 2 and 4*
- This option falls short by incorrectly including statement 2, which asserts a female predominance for RCC. **RCC has a male predominance**, with a male-to-female ratio of about 2:1 [1].
- This option also omits statement 3, which correctly identifies the major subtypes (clear cell, papillary, and chromophobe), even though statements 1 and 4 are correct.
*2, 3 and 4*
- This option incorrectly includes statement 2, which states a female preponderance for RCC; **renal cell carcinoma is actually more prevalent in males** [1].
- While statements 3 and 4 are correct regarding the major subtypes and the role of surgery in organ-confined disease, the factual error in statement 2 invalidates this option.
Renal Physiology Indian Medical PG Question 4: GFR is increased by all except?
- A. Renal stone in ureter (Correct Answer)
- B. Efferent arteriole constriction
- C. Increased renal blood flow
- D. Decreased oncotic pressure
Renal Physiology Explanation: ***Renal stone in ureter***
- A renal stone in the ureter causes **post-renal obstruction**, leading to a buildup of pressure in the Bowman's capsule, which in turn **reduces GFR**.
- **Obstruction** impedes urine outflow, thereby increasing **hydrostatic pressure** in the tubular system and opposing filtration.
*Efferent arteriole constriction*
- **Constriction of the efferent arteriole** increases the **hydrostatic pressure** within the glomerulus, which promotes an increase in GFR.
- This constriction retains blood in the glomerulus, thereby increasing the **filtration pressure**.
*Increased renal blood flow*
- An **increase in renal blood flow** elevates the **glomerular hydrostatic pressure** and increases the amount of plasma available for filtration, leading to an **increased GFR**.
- A higher flow rate also helps to maintain a more constant **glomerular capillary oncotic pressure**, preventing early filtration equilibrium.
*Decreased oncotic pressure*
- **Decreased oncotic pressure** in the glomerular capillaries (e.g., due to hypoproteinemia) reduces the osmotic force opposing filtration.
- This reduction in opposing force allows for a net increase in the **filtration pressure**, thereby **increasing GFR**.
Renal Physiology Indian Medical PG Question 5: Proteoglycan present in the glomerular basement membrane is?
- A. Keratan sulfate 1
- B. Keratan sulfate 2
- C. Heparan sulfate (Correct Answer)
- D. Chondroitin sulfate
Renal Physiology Explanation: ***Heparan sulphate***
- Heparan sulphate is a key component of the **glomerular basement membrane** (GBM), crucial for its **negative charge and filtration function** [1][2].
- It plays a significant role in **filtration barrier** properties and affects the permeability of the GBM to proteins [1].
*Keratan sulphate 1*
- Predominantly found in **cartilage** and **corneal tissue**, not associated with the glomerular basement membrane.
- It contributes to **mechanical support** but lacks the essential role in renal filtration.
*Keratan sulphate 2*
- Similar to Keratan sulphate 1, this variant is involved in **cartilage** but not in the structure of the glomerular basement membrane.
- Has distinct functions related to **tissue hydration** rather than the filtration dynamics of the GBM.
*Chondroitin sulphate*
- Commonly located in **cartilage** and connective tissues, it does not play a significant role in the structure of the glomerular basement membrane.
- While it assists in **cell signaling** and regeneration, it does not influence the GBM permeability like heparan sulphate.
**References:**
[1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 905-907.
[2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. With Illustrations By, pp. 34-35.
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