What is the major part of the kidney called?

Appeared in: CIP Ranchi 2023

Explanation

The nephron is defined as the basic structural and functional unit of the kidney.
Each kidney is composed of approximately 800,000 to 1 million nephrons.
The primary function of the nephron is to filter blood plasma, reabsorb necessary materials, and excrete the remaining fluid and waste as urine.
While other structures are larger anatomically, the nephron is the 'major part' in terms of physiological function.

Option A: The cortex is the outer anatomical region of the kidney. Although it contains the renal corpuscles (part of the nephron), it is a larger structural zone, not the functional unit itself.
Option C: The hilum is a specific anatomical landmark—the concave area on the medial side where the renal artery, vein, and ureter connect to the kidney. It is an entry/exit point, not a functional part.
Option D: The medulla is the inner anatomical region of the kidney, containing the renal pyramids. It houses parts of the nephron, like the loop of Henle and collecting ducts, but it is a large region, not the individual functional unit.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Anatomy and Physiology of the Kidney as background academic context rather than a clinical decision trigger.
Understanding the nephron is fundamental for nurses, as its damage (nephropathy) is the basis for most kidney diseases.
Nurses monitor renal function by assessing lab values for waste products that healthy nephrons should clear, such as blood urea nitrogen (BUN) and serum creatinine.
Many medications are excreted by the kidneys, so a patient's renal function (a measure of nephron health) directly impacts drug dosage and safety.

How to Approach the Question

First, identify the keywords in the question: 'major part' and 'kidney'.
Recognize that 'major part' can be interpreted in two ways: the largest anatomical structure or the primary functional unit.
Analyze the options provided. 'Cortex', 'Medulla', and 'Hilum' are all macroscopic anatomical structures.
Recall that the 'Nephron' is the microscopic unit responsible for the kidney's actual work of filtration and urine production.
In a physiological or nursing context, the functional unit is typically considered the most important or 'major' part. Therefore, the nephron is the most accurate answer.

Concept Tested & Keywords

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E6 Histology Inderbir 11e p. 68-70

E6 Physiology Guyton 4SAE Part 2B p. 10-12

E6 Anatomy BDChaurasia V2 10e Part 2 p. 99-101

Practise the full CIP Ranchi 2023

Attempt every question from this paper in a timed mock, then review the full solution for each one.