The fight-or-flight response is characterized by the following EXCEPT ?

RRB Nsg. Superintendent-21 July 2019 (Shift-2nd)

Applied Physiology

Easy

Appeared in: RRB Nsg. Superintendent-21 July 2019 (Shift-2nd)

Explanation

The fight-or-flight response is a function of the sympathetic nervous system, preparing the body for intense physical activity.
A key feature of this response is an increase in heart rate and contractility to boost the supply of oxygenated blood to muscles.
This results in a significant INCREASE in cardiac output (the volume of blood pumped by the heart per minute).
Therefore, a 'decrease in cardiac output' is directly opposite to the actual physiological change and is the correct exception.

Option A: This is a characteristic of the fight-or-flight response. The airways (bronchioles) dilate and breathing rate increases to maximize oxygen supply for muscles.
Option B: This is a characteristic of the fight-or-flight response. Widespread vasoconstriction and increased cardiac output cause a rise in blood pressure to improve perfusion to vital organs and muscles.
Option D: This is a characteristic of the fight-or-flight response. Adrenaline and increased blood flow to the brain heighten awareness, focus, and sensory perception to better manage the threat.

Visual 1: Diagram - An infographic illustrating the effects of the sympathetic nervous system on various organs during the fight-or-flight response (e.g., dilated pupils, increased heart rate, dilated bronchi, inhibited digestion). This helps visualize the systemic nature of the response.
Visual 2: Flowchart - A flowchart showing the pathway from a perceived stressor to the activation of the adrenal medulla, release of epinephrine/norepinephrine, and the resulting physiological changes. This clarifies the hormonal and neural sequence of events.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Physiology of the fight-or-flight response (sympathetic nervous system) as background academic context rather than a clinical decision trigger.
Understanding the fight-or-flight response is crucial for nurses to recognize signs of acute stress, anxiety, or shock in patients. Tachycardia, hypertension, and rapid breathing can indicate a patient is experiencing significant physiological stress.
Many medications used in nursing, such as beta-blockers (e.g., metoprolol) and sympathomimetics (e.g., epinephrine), directly interact with this pathway. Beta-blockers blunt the fight-or-flight response, while sympathomimetics trigger it.
What if? - If a patient on a beta-blocker experiences a stressful event, their heart rate and blood pressure may not increase as expected. The nurse must look for other, more subtle signs of distress, such as restlessness, pallor, or diaphoresis, as the classic signs are masked by the medication.

How to Approach the Question

First, identify the keyword 'EXCEPT'. This signals that you are looking for the option that is NOT true or is the outlier among the choices.
Next, recall the purpose of the 'fight-or-flight' response: to prepare the body for intense physical exertion in response to a threat.
Evaluate each option based on this purpose. Ask yourself, 'Does this change help the body fight or run away?'
Option A (more oxygen), Option B (higher BP for blood flow), and Option D (sharper mind) all support this purpose.
Option C (less cardiac output) is counterproductive. The body needs MORE blood pumped, not less. This makes it the logical exception.
Confirm that a decrease in cardiac output is the opposite of what occurs, solidifying it as the correct answer.

Concept Tested & Keywords

Concept Tested: Physiology of the fight-or-flight response (sympathetic nervous system)
Stem keywords: fight-or-flight response
Lead-in keywords: EXCEPT
Negative lead-in flag: The question asks for the exception, not the rule.

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