Quick (incomplete) Breakdown of the Central Nervous System (CNS)..
CENTRAL NERVOUS SYSTEM (CNS) = Brain & Spinal Cord & Nerves
- Somatic Nervous System (SNS) = Motor cortex, most muscles, conscious movement
- Autonomic Nervous System (ANS) = Every function that happens automatically
AUTONOMIC NERVOUS SYSTEM (ANS)
- Parasympathetic Nervous System = Rest & Digest
- Sympathetic Nervous System = Fight or Flight
The parasympathetic & sympathetic aren't exactly binary, but they're close. Only 1 system can really be operating fully functional at one time. Essentially when any of the systems in 1 turn on, the others turn off. For very good reason. It doesn't really matter if you'd have digested that meal & fought off that cold... If the bear eats you.
In an emergency? The sympathetic nervous system YANKS all available resources to itself. And some very predictable things happen.
-
All of your blood? Gets pulled into your core. That not only provides vital oxygen & nutrients to your vital organs and biggest muscles, but prevents a LOT of bleeding, should you get cut. Even big bad serious cuts will ooze instead of gush your life out, because your body has pulled it close. <<< A few side effects of that? You'll be pale & cold, unless you're moving.
-
Your digestive system shuts off almost completely. Total waste of energy (and digestion is 1:2 biggest energy sucks the body has, the other is ratiocination). Part of this process includes "voiding" ie Puking, pissing yourself, & shitting yourself. Piss scared & shit scared? Ain't just a turn of phrase. The harder your sympathetic system has turned on? The harder the void response. If you're just a little nervous? Like going for a job interview? You'll need to pee, almost constantly. Before getting ready, before leaving the house, before you check in with reception, maybe even after checking in with reception, etc. If you're flat out terrified? Yep. New pants needed. <<< A few side effects of this? Voiding (as mentioned) to various degrees, also no appetite, which includes dry-mouth (no need to be all lubricated, if nothing is sliding down tube!).get
-
Your lungs completely change the blood gas mix & dilate like crazy to fascinate that (ie short shallow breaths, hyper oxygenate your blood (more POWER! Go go go! Muscles burn it! NOW!) ...whilst raising co2 levels... Which regulates the feeling of "needing" to breathe. So if you
can't breathe for an extended period of time? No worries. (Strangled, drowning, crushed, etc.) It literally buys you MINUTES of consciousness -to save your ass- without air. Of course, the downside of hyperventilating is that if you *arent* running/fighting for your life? You'll get dizzy & pass out.
-
Your heart beats faster to propel super-oxygenated blood to everywhere that needs it
-
Immune System Shuts off (ever wonder why if you go to the gym for a couple hours when you're not sure if you're gonna have a cold or not, you get a cold? That's why). Most of the time the immune system shuttin off here and there throughout the day is no worries. But people under high levels of stress? Get sick... A lot... Very commonly.
List goes on, actually, but sound familiar?