& x20;Which physiological abnormality increases renin secretion? - INI-CET EXAM -2026

INI-CET EXAM -2026

Applied Physiology

Easy

Appeared in: INI-CET EXAM -2026

Explanation

The primary stimulus for renin secretion is a decrease in the effective intravascular volume.
Specialized cells in the kidney, the juxtaglomerular (JG) cells, act as baroreceptors.
When these cells detect decreased perfusion pressure in the afferent arteriole, they release renin.
Renin initiates the RAAS cascade, which ultimately raises blood pressure and restores renal perfusion.

Option B: Increased extracellular fluid volume leads to increased renal perfusion and stretching of the cardiac atria. This suppresses renin release and stimulates the release of Atrial Natriuretic Peptide (ANP), which promotes sodium and water excretion to lower blood volume and pressure.
Option C: Elevated renal perfusion pressure is the opposite of the stimulus for renin release. High pressure in the afferent arterioles directly inhibits the juxtaglomerular cells from secreting renin.
Option D: An elevated sodium (NaCl) load delivered to the macula densa in the distal tubule signals that the glomerular filtration rate (GFR) is high. This triggers a feedback mechanism (tubuloglomerular feedback) that causes vasoconstriction of the afferent arteriole and inhibits renin release from the adjacent JG cells.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Regulation of renin secretion by the Renin-Angiotensin-Aldosterone System (RAAS) as background academic context rather than a clinical decision trigger.
Understanding renin regulation is fundamental to pharmacology, particularly for antihypertensive medications like ACE inhibitors (e.g., lisinopril) and Angiotensin II Receptor Blockers (ARBs) (e.g., losartan), which interrupt the RAAS pathway to lower blood pressure.
Nurses monitor for signs of reduced renal perfusion (e.g., hypotension, low urine output) in conditions like hemorrhage, heart failure, and dehydration, as these states activate the RAAS, leading to fluid retention and vasoconstriction.
What if? - If a patient has renal artery stenosis (narrowing of the artery to one kidney), that kidney would perceive low perfusion pressure even if systemic blood pressure is normal or high. This would lead to chronic, excessive renin secretion and difficult-to-control hypertension (renovascular hypertension).

How to Approach the Question

First, identify the core physiological process in the question: the regulation of renin secretion.
Recall the purpose of the Renin-Angiotensin-Aldosterone System (RAAS), which is to increase blood pressure and blood volume.
Think logically: what condition would necessitate an increase in blood pressure? A state of low pressure or low volume.
Evaluate each option. 'Reduced renal perfusion pressure' directly translates to low blood pressure in the kidneys, which is the primary trigger for the RAAS.
Eliminate the other options as they represent states of high volume or pressure (B, C) or high sodium delivery (D), all of which would signal the body to decrease renin secretion to lower blood pressure.

Concept Tested & Keywords

Concept Tested: Regulation of renin secretion by the Renin-Angiotensin-Aldosterone System (RAAS).
Stem keywords: renin secretion, physiological abnormality
Lead-in keywords: increases

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