The Autonomic Nervous System usually operates without conscious control, it is regulated by the hypothalamus and the brain stem. The efferent parts of the ANS are divided into the Sympathetic and the Parasympathetic. Some organs in the body receive impulses from both of these, this is called dual innervation.
The Sympathetic system takes over in any physical or mental stress, for example;
- and emergency.
It is accompanied by the body getting ready to implement the fight or flight response, this means:
- dilation of pupils
- increase of heart rate and blood pressure
- decrease in blood flow to nonessential organs (e.g. focus away from digesting food)
- increase in blood flow to skeletal & cardiac muscle
- airways dilate & respiratory rate increases
- and blood glucose level increase
I can identify a few times when the fight or flight response kicked in,
A few weeks ago two men tried to break into the secure building I live in at 3am, my body was flooded with adrenaline and cortisol even though I knew I was safe. I could feel my heart racing and suddenly had such amazing energy even though I had just been woken up at 3 am by breaking tiles. I went out and started to yell at them, and ended up man handling one of them, not realising that I felt somewhat stronger than usual, I ended up piercing the skin when I grabbed one guy by the arm which I didn’t notice until after the fiasco.
On reflection, I wouldn’t actually be threatening to two very intoxicated big burly men. It took around an hour for my body to calm down afterwards and I felt like I really needed to go for a run or do something to expel all the excess energy.