Which hormone is known as the 'Emergency Hormone' or 'Flight-or-Fight' hormone?

RML Lucknow - 2021

Applied Physiology

Easy

Appeared in: RML Lucknow - 2021

Explanation

Adrenaline, also known as epinephrine, is secreted by the adrenal medulla in response to stimulation from the sympathetic nervous system during stressful situations.
It is the primary hormone responsible for initiating the 'fight-or-flight' response, which prepares the body for immediate and intense physical action.
The major effects of adrenaline release include increased heart rate, elevated blood pressure, bronchodilation, and a rise in blood glucose levels to provide quick energy to muscles.

Option A: Thyroxine, produced by the thyroid gland, is primarily responsible for regulating the body's long-term basal metabolic rate, growth, and development. It is not involved in the acute, rapid response to emergencies.
Option B: Insulin is secreted by the pancreas to lower blood glucose levels by facilitating the uptake and storage of glucose in cells. Its function is anabolic (building up stores), which is the opposite of the catabolic (breaking down stores for energy) action needed during a fight-or-flight response.
Option D: Estrogen is a primary female sex hormone produced mainly in the ovaries. It is responsible for the development of female secondary sexual characteristics and regulation of the menstrual cycle, and has no direct role in the body's acute stress response.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Function of Adrenaline as the 'Fight-or-Flight' Hormone as background academic context rather than a clinical decision trigger.
Nurses must understand the effects of adrenaline (epinephrine) as it is a critical medication used in emergencies like cardiac arrest (asystole, PEA), anaphylaxis, and severe asthma attacks to stimulate the heart, reverse bronchoconstriction, and raise blood pressure.
Recognizing the physiological signs of an adrenaline surge (tachycardia, hypertension, pallor, sweating, anxiety) in patients can help a nurse quickly identify acute stress, pain, fear, or an underlying medical crisis like hypoglycemia or shock.
What if? - If a patient is taking a beta-blocker medication (e.g., metoprolol), their response to both endogenous and exogenous adrenaline will be blunted. They may not exhibit the expected tachycardia during a stressful event, which is a crucial consideration for nurses assessing their hemodynamic stability.

How to Approach the Question

First, identify the key phrases in the question: 'Emergency Hormone' and 'Flight-or-Fight'. These terms are synonymous and point to a specific physiological stress response.
Recall the basic functions of the major hormones listed in the options from your study of the endocrine system.
Associate the 'fight-or-flight' response with the sympathetic nervous system and the hormone released by the adrenal medulla under its stimulation.
Evaluate each option based on this association: Thyroxine (metabolism), Insulin (glucose storage), Adrenaline (stress response), and Estrogen (reproduction).
Conclude that Adrenaline is the only hormone listed that is directly responsible for the acute emergency response.

Concept Tested & Keywords

Concept Tested: Function of Adrenaline as the 'Fight-or-Flight' Hormone
Stem keywords: Emergency Hormone, Flight-or-Fight hormone
Lead-in keywords: Which hormone
Clinical cues: The care setting changes urgency, monitoring level, and the expected nursing action.
Negative lead-in flag: false

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