When you perceive danger, your body responds instantly with a series of chemical and muscular changes.
Your eyes are the first to respond to danger. When the eyes see a threat, the pupils dilate, letting more light in to give a clearer view of the threat.
The brain's hypothalamus initiates the body's fight-or-flight response by simultaneously activating both the sympathetic nervous system (which triggers the nerves) and the adrenal-cortical system (which dumps hormones into the bloodstream). The action of the sympathetic nervous system causes the body to become tense and very alert. Meanwhile, the hypothalamus alerts the pituitary gland to activate the adrenal-cortical system, which releases about 30 different hormones to prepare the body to handle the threat. All maintenance stops, digestion stops, everything not needed to get you through the next few seconds stops.
The hormones released into the body during a danger response cause the following physical reactions:
Scared people will often turn pale. During an emergency, less blood flows through the skin and more blood is directed to vital parts of the body that need it, such as the heart and muscles.
Once the threat diminishes, the body releases the hormone cortisol to calm itself back down to normal. The entire fight-or-flight cycle is part of a defense mechanism that has developed over thousands of years.
Stages of Conflict: