A to Z of the Fight or Flight Response

Summary

This video explores the 'fight-or-flight' response, a physiological reaction to perceived threats. It explains how the body efficiently prepares for danger by activating the sympathetic nervous system and releasing stress hormones. The process is broken down into four steps: sensory perception, brain processing, message relay, and physiological response. Key reactions include increased heart rate, energy mobilization, and heightened alertness, all designed to help the body either fight or flee. The video emphasizes the importance of this response in survival, detailing how the body returns to calm once the threat is gone.

Takeaways

• ⚡ The fight-or-flight response is a physiological reaction to perceived harmful events, attacks, or threats to survival.
• 🧠 The body's preparation involves efficient energy usage by activating and deactivating different processes.
• 🔄 Messages are delivered through two systems: the sympathetic nervous system and the endocrine system.
• 👁️ Sensory perception is the first step, where sensory information (from eyes, ears, etc.) is collected and converted into electrical signals.
• 🔍 The brain processes the sensory information in the thalamus and sends it to the amygdala to assess fear and emotion.
• 🧬 The hypothalamus controls the fight-or-flight response by releasing hormones and activating the sympathetic nervous system.
• 💉 ACTH is released from the anterior pituitary gland, triggering the release of cortisol (a stress hormone) and adrenaline.
• 🏃‍♂️ Adrenaline causes physiological changes, such as increased heart rate, faster breathing, and energy mobilization.
• ⚡ Blood flow is redirected from the digestive system to the skeletal muscles, enabling the body to respond more efficiently.
• 👁️ The fight-or-flight response also causes dilation of pupils, tunnel vision, and loss of hearing, preparing the body for action.

Q & A

What is the fight-or-flight response?

The fight-or-flight response, also known as hyper-arousal or acute stress response, is a physiological reaction to perceived harmful events, attacks, or threats to survival, preparing the body to either confront or flee from danger.

What triggers the fight-or-flight response?

The fight-or-flight response is triggered by sensory information that signals a harmful event or threat to survival, activating either the sympathetic nervous system or the endocrine system.

What role does the sympathetic nervous system play in the fight-or-flight response?

The sympathetic nervous system activates different body processes to prepare for immediate action, sending signals to release hormones like adrenaline and preparing the body for either fighting or fleeing.

How does the brain process sensory information during the fight-or-flight response?

Sensory information travels to the brain's thalamus, which acts as a relay station, sending data to the amygdala for emotional and fear processing. The amygdala assesses the situation and relays it to the hypothalamus, which controls the body's response.

What is the role of the hypothalamus in the fight-or-flight response?

The hypothalamus controls both the sympathetic nervous system and the endocrine system. It releases corticotropin-releasing hormone (CRH) to signal the pituitary gland to release adrenocorticotropic hormone (ACTH), triggering the release of stress hormones like cortisol.

What physiological changes occur during the fight-or-flight response?

Physiological changes include increased heart rate, faster breathing, dilation of pupils, tunnel vision, muscle vasodilation, and digestive vasoconstriction to prioritize energy for muscles needed in the response.

How does adrenaline affect the body during the fight-or-flight response?

Adrenaline stimulates the liver to convert glycogen to glucose for energy, increases heart rate and breathing rate, and redirects blood flow to muscles to prepare for action. It also enhances oxygen and nutrient delivery to skeletal muscles.

What happens to the body after the stress stimulus is gone?

Once the stress stimulus is gone, the body returns to a calm state by metabolizing stress hormones and restoring homeostasis, ensuring internal balance and recovery.

What is the role of the adrenal gland in the fight-or-flight response?

The adrenal gland releases adrenaline in response to signals from the sympathetic nervous system and cortisol after stimulation by ACTH, both hormones being crucial for the fight-or-flight response.

How does the fight-or-flight response impact vision and hearing?

During the fight-or-flight response, pupils dilate to improve vision, often resulting in tunnel vision, while hearing may be temporarily reduced as the body focuses on processing critical survival stimuli.