Fight or Flight physiological responses – so much more than an instinct

Source CC BY-SA 4.0

There are times in everyone’s life that we panic. It may be a brief instance where you trip and fall. It may be the first day at school or the first date with someone you’re enamoured with. It may simply be that an unexpected bill comes in the mail and you are on a tight budget.

For most of us when this happens, to a greater or lesser degree, our bodies instinctively stress. Depending on the level of shock to the system, and the type (whether it’s a pleasurable anticipation or not so) anything from a tiny trickle to an almighty gush of hormones gets released into our bodies to ready us for any action we may need to take.

In common terms: The Fight or Flight Response.

This is a base instinct that pretty much any living creature has to some extent or another.

Source: Tomdozier, CC BY-SA

Beyond what we know from TV and school, internet and books (yes we still use books), what do you know about your body? What do you know about how things work when you get a call from the person you’ve just been interviewed by for that dream job? What happens down at the molecular level when we here a screech of brakes and have nowhere to go? Or a newborn baby doesn’t cry with it’s first breath, or even when it does? How does our body manage to get us ready to deal with an unexpected ordeal?

First of all, you have to perceive that there is a problem. So electrical impulses go from the eyes, ears, skin, nose or mouth at lightning speed to the brain, specifically to the Amygdala. In the case of the eye, the equivalent of 875,000 bits of information can be transmitted per second. Other nerve impulses can react as fast as 119m/s.

Source: Patrick J. Lynch, CC BY 2.5

The situation is assessed, and an urgent signal is then sent to the hypothalamus. The hypothalamus sets two systems alight by electrical impulse and hormonal release – a bit like a nerve shot. One system, the corticotropin-releasing factor (CRF), releases a hormone which heads off to the pituitary gland. That in turn releases adrenocorticotropic hormone (ACTH).

ACTH sets off to the adrenal gland (which isn’t just for Adrenalin believe it or not). Up to 30 separate hormones are then flushed into the body at speeds we’d struggle to comprehend. In fact, it is so instantaneous if we could physically move our whole body that fast we could probably make it to Mars in a day! (not actual factoid)

At the SAME TIME, the hypothalamus sends flash nerve messages directly to the sympathetic nervous system (we have two nervous systems – but that’s a different post). The electrical signals travel to two points - to the adrenal medulla to instruct it to release two separate hormones (adding to the 30 plus from the other route) and to the skin and muscles which, at a micro level, smooths the muscles, tightens the skin and heightens sensitivity, and backs up the hormonal signals to the glands throughout the body.

Then, at the same point in time the hormones rush the bloodstream. Nerves, muscles, tendons, electrical impulse reactions, sight, smell, sound, taste, touch are all heightened.

The system readies to stand and fight – muscle tension increases (this can be to the point where the vocal chords are constricted and why some people in fear can’t scream (but can ‘growl’) - Muscle Tension Dysphonia). Posture changes, centre of gravity and spacial awareness all become paramount. Breathing increases to bring in more oxygen to ignite muscle movement. Pain receptors are dampened down = No point ouching over a cut if your life is in danger.

Source - Lmbuga, CC BY 2.0

You can see all this more so in animals. A cat fluffing up or a bear setting back on its hind paws. They don’t think “Oh there’s a threat I’ll make myself look big and strong” – it’s a reaction. And if they fight they don’t go looking for a band-aid because a claw caught them. They probably wouldn’t even notice all but the most serious of wounds. We react in exactly the same way. It just doesn’t seem so obvious most of the time. It’s the fight and flight at work.

In a moment where the threat appears to be so significant we know that we could not fight, flight reactions come into play. Again, this is a fraction-of-a-moment-in-time assessment (the brain is darn clever don’t you think?).

The reaction can include increasing muscle tension ready for running, but also it increases breathing (in the event you’ve calmed down already!) hearing and sight ability over and above other senses so we can track where we are going and what our surroundings and options consist of at a much quicker rate than when we're bobbling around under normal circumstances.

In some instances, the fight or flight hormones’ rush causes an off-load of weight. Food ejection and/or waste ejection is immediate (vomiting or bowel/bladder emptying). There’s no control. Someone in a situation so scary they truly fear for their life isn’t able to control this if the brain deems it necessary.

[Source: woodleywonderworks, CC BY 2.0](Source: woodleywonderworks, CC BY 2.0)

So now you know why your stomach knots and you feel queasy waiting for that first date to arrive – the fear that they won’t (or that they will), is minor in the grand scheme of things but your body doesn’t know that.

Think about a time when have had to stand up and speak in public for the first time, or were in a school play, or took your first flight.

Now think about the bumps on your skin, the tension in your muscles, the urge to pee even though you’ve just been.

Consider the stories you hear of the mother who lifted a massive object off her child even though she’s probably 5 feet tall and slim, or the guy who held back a falling tree for his wife to move before it fell. Acts of super strength. It’s all the same reaction. It’s all to do with increased strength and awareness, commonly called 'The Adrenalin Rush'.

But to me, the most fascinating thing of all is that it’s ALL instant, faster than a blink of the eye the body had done all of this and readied you for what ever it is you need to do to survive.

What’s even more fascinating is that if we go further, deeper in – it’s all a bunch of chemicals – nothing more than chemical reactions with a touch of electricity. I may write about that someday soon.

How amazing we are!

References:
Livescience - information transfer speeds from eye to brain

British voice association - Dysphonia

Young Diggers - Fight or flight

Thanks to my old college tutors for exciting my brain in this subject and to @mobbs for post guidance