Which of the following organs play(s) the primary role in maintaining fluid and electrolyte balance in the hu… - RRB Nsg. Superintendent-2026 (Shift -3rd)

RRB Nsg. Superintendent-2026 (Shift -3rd)

Applied Physiology

Easy

Appeared in: RRB Nsg. Superintendent-2026 (Shift -3rd)

Explanation

The kidneys are the primary organs for regulating the body's fluid and electrolyte balance, a process known as homeostasis.
They filter approximately 180 liters of plasma each day, selectively reabsorbing what the body needs and excreting the rest as urine.
This intricate process allows the kidneys to control the volume and composition of body fluids, including the levels of crucial electrolytes like sodium, potassium, and calcium.
The kidneys' function is influenced by hormones such as Antidiuretic Hormone (ADH) and aldosterone, which fine-tune water and sodium retention to meet the body's needs.

Option A: The stomach, as part of the gastrointestinal tract, is primarily involved in the digestion and absorption of ingested fluids and nutrients. It does not regulate the overall systemic fluid and electrolyte balance.
Option C: The lungs' main role is in gas exchange and maintaining acid-base balance by regulating carbon dioxide levels. While they do cause insensible water loss through exhalation (around 300 mL/day), they do not regulate electrolyte concentrations.
Option D: The liver plays a supportive role. It produces angiotensinogen, a precursor in the Renin-Angiotensin-Aldosterone System (RAAS), and synthesizes albumin, which helps maintain oncotic pressure. However, the kidneys are the organs that execute the final regulation by excreting or retaining fluid and electrolytes.

Visual 1: Diagram: The human urinary system, highlighting the kidneys, ureters, bladder, and urethra to illustrate the pathway of urine formation and excretion.
Visual 2: Infographic: The process of filtration, reabsorption, and secretion within a nephron. This visual would show how the kidney selectively manages water and electrolytes to maintain balance.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Primary organ for fluid and electrolyte homeostasis as background academic context rather than a clinical decision trigger.
In nursing practice, monitoring kidney function is fundamental to assessing a patient's fluid and electrolyte status. This includes tracking urine output, daily weights, and laboratory values like Blood Urea Nitrogen (BUN) and creatinine.
A sudden change in urine output is a critical sign. For example, an output below 30 mL/hour in an adult may indicate decreased renal perfusion and the onset of acute kidney injury.
What if? If a patient has chronic kidney disease (CKD), their kidneys lose the ability to regulate fluid and electrolytes effectively. The nurse must then vigilantly monitor for signs of fluid overload (edema, hypertension, crackles in the lungs) and dangerous electrolyte imbalances like hyperkalemia, which can lead to fatal cardiac arrhythmias.

How to Approach the Question

First, identify the keywords in the question: 'primary role' and 'fluid and electrolyte balance'. This indicates you need to find the organ with the most significant and direct control.
Next, systematically review the main function of each organ listed in the options.
Evaluate how each organ's function relates to the overall regulation of the body's water and salt content.
Compare the regulatory impact. While the lungs, stomach, and liver contribute, the kidneys' ability to filter the entire blood volume and produce urine with variable concentration gives them the most powerful and direct control.
Therefore, conclude that the kidneys are the primary regulators.

Concept Tested & Keywords

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