Acid base balance is regulated by kidney by exchange by excreting hydrogen ion and electrolytes to maintain t… - RUHS, Jaipur, M.Sc Nursing Entrance Exam-2015

RUHS, Jaipur, M.Sc Nursing Entrance Exam-2015

Medical Surgical Nursing

Easy

Appeared in: RUHS, Jaipur, M.Sc Nursing Entrance Exam-2015

Explanation

The primary function of excreting hydrogen ions (H+) by the kidneys is to remove excess acid from the body.
This process is crucial for maintaining the blood plasma pH within the narrow and slightly alkaline range of 7.35 to 7.45.
Simultaneously, the kidneys reabsorb bicarbonate (HCO3−), a base, which buffers the blood and counteracts acidity.
This renal mechanism provides a long-term and powerful solution to acid-base disturbances.

Option A: While the excretion of H+ ions often involves an exchange with other electrolytes like sodium (Na+), the primary purpose of this specific process is to regulate pH, not the overall balance of all electrolytes.
Option B: The specific gravity of urine measures the concentration of solutes and is primarily an indicator of the body's hydration status and water balance, which is regulated by Antidiuretic Hormone (ADH).
Option C: Filtering protein is a function of the glomerulus. In a healthy kidney, large molecules like proteins are not filtered into the urine. The presence of significant protein in urine (proteinuria) is a sign of glomerular damage, not a normal regulatory mechanism.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Renal regulation of acid-base balance as background academic context rather than a clinical decision trigger.
Nurses use Arterial Blood Gas (ABG) analysis to assess a patient's acid-base status. Understanding the kidney's role is vital for interpreting metabolic acidosis and alkalosis.
In patients with chronic kidney disease (CKD), the ability to excrete acid is impaired, often leading to chronic metabolic acidosis, which requires careful monitoring and management.
What if? If a patient develops respiratory acidosis from retaining CO2, the kidneys will compensate over 2-3 days by increasing H+ excretion and generating more HCO3− to help normalize the blood pH.

How to Approach the Question

First, identify the core physiological process mentioned in the question: the kidneys are excreting hydrogen ions (H+).
Recall the role of H+ ions in the body. A higher concentration of H+ makes a fluid more acidic, and a lower concentration makes it more alkaline. pH is the measure of this concentration.
Connect the action (excreting acid) with its logical purpose (maintaining pH balance). The body must get rid of excess acid to prevent the blood from becoming too acidic.
Evaluate the options based on this connection. 'Electrolyte balance' is related but secondary. 'Specific gravity' pertains to water balance. 'Filtering protein' is a separate glomerular function. 'Normal pH of blood plasma' is the direct and primary goal of regulating acid levels.

Concept Tested & Keywords

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