Flight-fight response is a physiological manifestation resulting from a perceived threat, which can be either real or imaginary. It is a chain reaction, which is also known by the names of ‘acute stress response’ and ‘hyperarousal.’ Walter Canon first described the phenomenon in the 1920s following observing the acute response made by animals when they perceived a threatening stimulus. As there are many hormones and body systems that contribute towards the manifestation of the flight-fight response, this article will discuss the mechanism of this response in relation to its psychological stimulation and physiological manifestations.
During an acute stress, the body’s sympathetic nervous system gets stimulated and thus releases the hormone acetylcholine. The pre-ganglionic sympathetic nerve ending is the major site of this release. Following its release, these hormones can stimulate the adrenal medulla to release the hormones adrenaline and noradrenalin into the circulation in a rapid and an efficient manner. These catecholamine hormones are thus responsible for the acute stress reaction, which is known as the flight-fight response shown by vertebrates and some of the other organisms.
In a more elaborate physiological explanation, it was stated that the locus ceruleus of the brain starts ‘firing’ when it receives a stimulus, which is perceived as a threat. In a serene state, the locus ceruleus also remains calm. However, as the stressful stimulus reaches the locus ceruleus from the sensory cortex through the thalamus, the noradrenergic activity would also rise. This has been recognized as the reason for a heightened alertness and attentiveness to the environment of a person when he or she experiences a stressful or threatening stimulus.
When talking about the physiological effects of the flight-fight response, almost all of them are geared to make the person or the animal react by either fighting or fleeing of which both require extra effort and efficiency in its coordinated function. Thus, some of the important bodily changes during this response include acceleration of the heart rate, rise in the respiratory rate, constriction of the peripheral blood vessels which are considered not essential for the present situation, dilatation of the blood vessels supplying the muscles…etc. These reactions are aimed at pumping enough blood towards the muscles and other important organs, which plays a vital role in the flight-fight reaction. By increasing the breathing rate, it is possible to provide the necessary amounts of oxygen to the growing demands of the bodily systems. In addition to the above responses, some of the other physiological reactions that take place during such instances include, inhibition of the stomach and upper intestinal functions, dilation of the pupil, relaxation of the bladder, inhibition of erection, inhibition of secreting saliva and tears, as well as shaking.
However, the adaptability of the flight-fight response towards the present social context seems to alter the behaviors expected in instances of acute stress or threatening stimulations. Thus, a person may engage in an angry argument as a result of a ‘fight’ response while the person would become socially withdrawn, abusive of various substances…etc as a result of a ‘flight’ response. Therefore, it is understandable that the flight-fight response is not just a bio-chemical reaction but is a complex interaction between many players.