The Neurochemical and Physiological Responses to Stress

Our minds and bodies work together to keep us safe by getting us ready to fight or run away when we encounter danger. The autonomic nerve system (ANS) governs these reactions, thus they happen without conscious thought. The ANS is split into two supplementary branches: the sympathetic nervous system, which prepares our nerves, organs, and muscles for a state of heightened arousal and regulates the "fight or flight" mechanism, and the parasympathetic nervous system, which regulates the body's calming mechanisms (as well as the "freeze" response) and is designed to shut down body systems or return the body to baseline arousal levels.

According to the accepted physiological model of the ANS, the sympathetic and parasympathetic systems exert opposing but complementary forces on one another to maintain homeostasis. A higher sympathetic response correlates with a lower parasympathetic reaction. Cats, who become alert to specific noises or movements but quickly revert to a calm state once they determine the situation is safe, are an excellent example of animals with perfect autonomic balance.

After the initial danger has been dealt with, the parasympathetic nervous system kicks in. In contrast to sympathetic activity, parasympathetic activity promotes relaxation and restores internal equilibrium. When the parasympathetic nervous system is stimulated, the body's muscles relax, resulting in a decrease in heart rate and blood pressure. Pupils contract, digestive juices start flowing, the bladder and intestines are ready to operate normally, and the immune system is able to return to normal.

Complex trauma: a developmental perspective on chapter 1 At the age of 13, several processes restart, including the creation of white blood cells. When your body is in parasympathetic mode, it's easier to relax and fall asleep.

The amygdala, a part of the limbic system and the brain's "defensive center," triggers the body's "fight or flight" reaction. (The amygdala serves a role like to that of a smoke detector.) The amygdala acts automatically in response to danger, and it does so by encoding sensory threat signals (including sights, sounds, bodily sensations, and odors) in a database.

The adrenaline stress response begins when the body senses danger and releases a series of neurochemicals into the circulation. Heart rate and breathing rate rise, oxygen supply to muscular tissue increases, and the brain's frontal cortex and other non-essential processes are shut down as these patterns of nerve cell firing and chemical release get the body ready for action.