Fight or Flight Response

Summary

In this educational video, Mr. Andersen explores the fight or flight response, explaining that the immediate reaction to danger is not due to adrenaline but rather the nervous system and muscles. He clarifies that adrenaline, or epinephrine, kicks in later, affecting various body systems by binding to cell surface proteins. This chemical messenger increases heart rate, breathing, and blood flow to muscles while slowing digestion, preparing the body to confront threats.

Takeaways

• 🚑 The fight or flight response is a physiological reaction that prepares the body to either confront or escape from a perceived threat.
• 🏃‍♂️ The immediate action of jumping out of the way of a car is not due to adrenaline but rather the rapid response of the nervous system and muscles.
• 🧠 The hypothalamus in the brain plays a central role in initiating the fight or flight response by sending signals throughout the body.
• 🫀 Adrenaline, also known as epinephrine, is released by the adrenal medulla in response to a threat and is a key chemical in the fight or flight response.
• 🔁 Epinephrine triggers a signal transduction pathway that converts glycogen to glucose in the liver, providing a quick energy source for the body.
• 💓 Epinephrine increases the heart rate by binding to proteins on the surface of heart cells and triggering a specific response within them.
• 🏋️‍♀️ The hormone causes vasodilation in muscles, increasing blood flow to these areas to enhance strength and readiness for action.
• 🔐 Epinephrine slows down the digestive system by vasoconstricting blood vessels, redirecting energy away from digestion during a threat.
• 👀 Other effects of epinephrine include faster breathing rates and dilated pupils, which are part of the body's overall response to prepare for action.
• 🔄 The fight or flight response illustrates how a single chemical signal can have varied effects on different cells and systems within the body.

Q & A

What is the fight or flight reaction?

The fight or flight reaction is a physiological response that occurs in response to a perceived harmful event, attack, or threat to survival. It is a part of the acute stress response and is also known as the 'acute stress reaction'.

How quickly does adrenaline respond in the fight or flight reaction?

Adrenaline does not respond as quickly as the initial physical reaction to a threat. The immediate response to getting out of the way of a car, for example, is due to the nervous system and muscles, not adrenaline.

What role does the nervous system play in the immediate response to a threat?

The nervous system processes the threat, sends signals to the muscles, and uses ATP to enable quick physical reactions, such as jumping out of the way of a car, without the involvement of adrenaline.

What is the primary function of epinephrine in the body during the fight or flight response?

Epinephrine, also known as adrenaline, is released during the fight or flight response to increase heart rate, dilate pupils, and mobilize glucose for energy. It prepares the body to either confront the threat or flee from it.

Where is the hypothalamus located and what is its role in the fight or flight response?

The hypothalamus is located near the center of the brain. It sends signals that initiate the fight or flight response by triggering the release of adrenaline from the adrenal medulla.

How does epinephrine affect the liver during the fight or flight response?

Epinephrine triggers a signal transduction pathway in the liver that converts glycogen into glucose, providing the body with an immediate energy source.

What is the effect of epinephrine on the heart and lungs during the fight or flight response?

Epinephrine increases the heart rate and breathing rate by triggering signal transduction pathways in the heart and lung cells, preparing the body for rapid action.

How does the digestive system respond to the presence of epinephrine during the fight or flight response?

Epinephrine causes vasoconstriction in the digestive system, slowing down digestion and redirecting blood flow away from the digestive organs to prioritize the body's response to the threat.

What is the purpose of the different responses to epinephrine in various parts of the body?

The different responses to epinephrine throughout the body are designed to ensure that the body can effectively deal with a threat. This includes increasing energy supply, enhancing sensory perception, and preparing the body for physical exertion.

Why does the body not need to focus on digestion during a fight or flight response?

During a fight or flight response, the body prioritizes immediate survival by redirecting resources away from non-essential processes like digestion, which is not critical for immediate survival.

How does the body's response to epinephrine contribute to the feeling of a 'rush' after a near-accident or a perceived threat?

The 'rush' feeling is a result of the body's release of epinephrine, which increases heart rate, breathing, and energy supply, preparing the body for a quick response to danger.

Outlines

00:00

🚑 Understanding the Fight or Flight Response

Mr. Andersen introduces the concept of the fight or flight response, using a video clip as an example. He explains that the immediate reaction to danger, such as jumping out of the way of a car, is not due to adrenaline but rather the nervous system and muscles responding quickly. The true fight or flight response kicks in after the immediate threat, causing symptoms like a fast heartbeat and rapid breathing. He emphasizes that this response is managed by the sympathetic nervous system and is centered around the brain, particularly the hypothalamus, which sends signals to the adrenal medulla to release adrenaline (epinephrine) into the bloodstream.

05:02

🏃‍♂️ The Impact of Epinephrine on the Body

This paragraph delves into the effects of epinephrine throughout the body. It explains how epinephrine binds to proteins on cell surfaces and triggers various responses depending on the location. In the liver, it converts glycogen to glucose for energy. In the heart and lungs, it increases the rate of heartbeat and breathing. Conversely, in the digestive system, it slows down digestion by vasoconstriction. The paragraph highlights how a single chemical signal can have diverse effects, preparing the body to either fight or flee from a threat.

Keywords

💡Fight or Flight Response

The fight or flight response is a physiological reaction that occurs in response to a perceived harmful event, attack, or threat to survival. In the video, this response is discussed as the body's way of preparing to either confront danger or escape from it. The example given is a person narrowly avoiding a car, which triggers a rush of adrenaline and other physiological changes to prepare the body for action.

💡Adrenaline

Adrenaline, also known as epinephrine, is a hormone and neurotransmitter that is released during stressful situations. It is part of the body's fight or flight response. In the script, it is mentioned that adrenaline is often incorrectly thought to be the immediate cause of a person's ability to react quickly to danger, but it actually takes time to be released into the bloodstream and thus is not the immediate cause of the quick reaction seen in the video example.

💡Nervous System

The nervous system is a complex network of nerves and cells that transmit signals between different parts of the body. It plays a crucial role in the body's initial response to threats, as it sends messages to muscles to react quickly. The video explains that the nervous system's rapid response to the sight of a car is what allows the person to jump out of the way, not the fight or flight response.

💡ATP (Adenosine Triphosphate)

ATP is the primary molecule for storing and transferring energy within cells. It is often referred to as the 'energy currency' of the cell. In the context of the video, ATP is mentioned as being ready to provide immediate energy for muscle contractions, allowing for a quick physical response to danger.

💡Hypothalamus

The hypothalamus is a region in the brain that links the nervous system to the endocrine system via the pituitary gland. It is involved in many important functions, including the regulation of body temperature, hunger, thirst, and the fight or flight response. The video describes how the hypothalamus sends signals that initiate the fight or flight response when it perceives a threat.

💡Adrenal Medulla

The adrenal medulla is the inner part of the adrenal gland, which is located on top of each kidney. It is responsible for the production of adrenaline (epinephrine) in response to stress. The video script explains that the adrenal medulla is activated by signals from the brain, leading to the release of adrenaline as part of the fight or flight response.

💡Signal Transduction

Signal transduction is the process by which a cell converts one kind of signal or stimulus into another. This is a crucial mechanism in cellular communication. In the video, signal transduction is described as the process by which epinephrine triggers specific responses in cells, such as the conversion of glycogen to glucose in the liver.

💡Glycogen

Glycogen is a form of glucose storage found in the liver and muscles. It is converted into glucose when the body needs a rapid release of energy. The video script uses glycogen as an example of how the body prepares for action during the fight or flight response by converting it into glucose to provide immediate energy.

💡Vasoconstriction

Vasoconstriction is the narrowing of blood vessels, which reduces blood flow. In the context of the fight or flight response, vasoconstriction occurs in non-essential areas, such as the digestive system, to redirect blood flow to areas that need it more, like muscles. The video explains that epinephrine causes vasoconstriction in the digestive system to slow down digestion during a stressful event.

💡Vasodilation

Vasodilation is the widening of blood vessels, which increases blood flow. This is particularly important during the fight or flight response, as it allows for increased blood flow to muscles, providing them with more oxygen and nutrients needed for action. The video script mentions that epinephrine causes vasodilation in the muscles to prepare the body for physical exertion.

Highlights

Introduction to the fight or flight reaction

Explanation of the immediate physical response to danger, separate from adrenaline

Role of the nervous system and muscles in the initial reaction to threat

Clarification that adrenaline does not act as quickly as the initial response

Description of the delayed fight or flight response involving adrenaline

Importance of the sympathetic nervous system in fight or flight

Role of the hypothalamus in initiating the fight or flight response

Connection between the brain and adrenal medulla in response to threat

Function of adrenaline (epinephrine) in the body during fight or flight

Circulation of epinephrine through the body and its effects on various organs

Conversion of glycogen to glucose in the liver due to epinephrine

Epinephrine's role in increasing heart rate and breathing rate

Impact of epinephrine on the digestive system during fight or flight

Vasodilation and increased blood flow to muscles due to epinephrine

The body's ability to have a single signal (epinephrine) with varied responses

Epinephrine's contribution to increased heart rate, faster breathing, and dilated pupils

Conclusion and summary of the fight or flight response

Transcripts

Hi. It's Mr. Andersen. Today I'm going to talk about the fight or flight

reaction. This is one of my favorite videos on YouTube. This is from youtube.com/RussiaToday.

So we got this person here walking down the street. All of a sudden they realize there's

a car coming and then they get out of the way. Now if I were to keep playing it the

guy jumps out of the car, comes running in this direction. But basically I want to talk

about what's going on. So once this guy sees the car, how does he number one get out of

the way? And then how does that affect his body? How does that affect the organs and

the chemistry and all of that inside his body. And so that whole thing is called the fight

or flight. And so when I ask students, you know, how does he get out of the way of the

car? The answer is always adrenaline. And the right answer is no, it's not adrenaline.

Adrenaline is not going to be able to get there that quickly. And so how does the guy

really get out of the way? Well, he's going to see the car coming. He's going to process

that in his brain. And then he's going to send a message down his nervous system. That

nervous system is going to be attached to muscles. And those muscles are going to have

ATP ready to go. And so the way he's able to jump out of the way and not get hit by

the car, doesn't have anything to do with the fight or flight response. It's simply

his nervous system, his muscles and just responding to that threat immediately. But if you've

ever been in a situation like that, where you just barely survive an accident or something

like that, all of the sudden you feel this rush of just your heart starts beating fast

or your breathing. You feel warm. Now that's part of the fight or flight response. Because

this guy right here, since he's living in a city, is able to just kind of walk back

on to the road and keep about his business. But back in the day if you were attacked by

a mountain lion or somebody else, you had to fight now. You had to flee. Or you had

to attack the attacker. And so all of that is part of what's called the sympathetic nervous

system. Or that system inside our body that allows us to fight or flight. And so let's

zoom inside this guy and talk a little bit more about how are the fight or flight works.

And so it's basically centered around his brain. And so in the center of his brain,

near the bottom we have something called the hypothalamus. So the hypothalamus, in that

area of the brain, is essentially going to send a signal. Now that signal, not only are

we getting signals that are going to the muscles that allow you to move, but it's going to

send a signal all the way down a nervous signal all the way down here. Because in the center

of our adrenal gland we have something called the adrenal medulla. It's connected nervously

to the brain. So the moment he sees that car and realizes he might die, there's a signal

being sent to the adrenal medulla or the center of the adrenal gland. It's going to give off

what's called adrenaline. And that adrenaline is epinephrine. Epinephrine is a chemical

signal that is going to be attached to the circulatory system. And so it's going to course

through the body. So as his heart beats faster and faster and faster epinephrine is going

to flow throughout the rest of the body. Now epinephrine is not going to go into the cells

of the body. It's simply going to, if we say this is a big liver cell, it's simply going

to bind to proteins on the surface of those cells. And so what's it going to do to the

liver? Well in the liver what it's going to do is it's going to trigger a signal transduction

pathway that's going to convert glycogen, glycogen that's found inside the cells of

the liver. And it's going to use that as glucose. Why is it doing that? Well glucose is our

energy supply and so now glucose is going to be coursing through our body along with

epinephrine. And so now we have a supply of energy so we can quickly breakdown that glucose.

Get ATP and we can do more out of it. But what's interesting is that epinephrine is

going to go other places in the body. And it's going to have different responses depending

on where it goes. And so what is epinephrine going to do to the cells that are in control

of the breathing? The cells of the lung. It's going to speed up that breathing rate. What's

epinephrine going to do when it goes to the cells of the heart? It's going to speed up

the rate of the heart beat. And so it's going to trigger a signal transduction pathway in

the heart that's very similar to the signal transduction pathway that we find in the liver

cells. However it's going to have a different response inside the cells. It's going to not

release glucose, but it's going to increase the rate of the beating of those cardiac cells.

What do you think would happen to the digestive system? Well epinephrine is going to go there

as well. But what it's going to do is it's going to vasoconstrict. So it's going to slow

down digestion. And so it's going to slow down those blood vessels that feed those areas

that allow us to breakdown and digest food. Because when you're getting out of the way

of a car or fighting an attacker, you don't really need to concentrate on breaking down

that bagel that you ate for breakfast. So it's going to shut that down. But it's going

to go to the muscles of your body. And it's going to vasodilate. And so it's going to

move more blood to those areas. And so our whole body is designed so we can have one

signal, that epinephrine, but it can have all these different responses throughout the

rest of the body. And so that's going to allow our body to respond to that threat. And that's

why your heart races. You breathe faster. Your pupils dilate. All that happens and you

can thank epinephrine for that. And it's that chemical response and the different either

gene expression or signal transduction pathways that we have as a result. And so I hope that's

helpful.