All the body organs work in strong coordination under the leading instructions of the nervous system, i.e., peripheral nervous system or autonomic nervous system. Similar is the case with the heart, which reacts differently in a normal and frightening situation. All the events carried out in our heart during a normal morning routine are commonly called the cardiac cycle. This cycle includes four adjacent stages, namely relaxation, inflow, contraction, and finally ejection. However, comprising these stages in generalized terms, it is usually quoted that the cardiac cycle comprises of two phases, systole, and diastole. The overall events followed the opening and closing of valves along with contracting and relaxing of heart chambers. During normal functioning, the deoxygenated blood turns to the right side through venous circulation, and finally, from the right ventricle, it is pumped towards the lungs for absorbing oxygen (Alraies et al., 2017).
However, during a frightening or dangerous situation, the heart beats faster to push the human body into a “fight-fright-or-flight” situation under the brain’s command. Meanwhile, the autonomic nervous system activates, and brain triggers the secretion of adrenaline and cortisol at once. In this way, the vital organs are supplied with oxygenated blood and additional nutrients to prepare them for reaction. Adrenaline and cortisol are carried throughout body through the bloodstream. The pumping of adrenaline results in the opening of bronchi due to increased levels of sugar and fats. Resultantly heartbeat and breathing rate increase manifold (Ibragimov et al., 2021).
Furthermore, the autonomic nervous system controls the homeostasis of the heart. In addition, the two branches of ANS play opposite roles in this regard. The sympathetic branch regulates the heart homeostasis at rest, while the parasympathetic is responsible for the “fight-fright-or-flight” response. As far as the autonomic and somatic peripheral nerve action is concerned, they act differently. Somatic peripheral nerves act through sensory as well as motor pathways which control muscular movement. On the other hand, autonomous action only depends upon motor pathways and controls the stimulation of hormones through receptors to act on the specific internal organ like heart.
Alraies, M. C., Garry, D. J., & Garry, M. G. (2017). Physiology of the normal and failing heart. In Congestive Heart Failure and Cardiac Transplantation (pp. 21-37). Springer, Cham.
Ibragimov, S., Rustamova, D., Ganieva, A., Zubaydilloeva, Z., & Raiimzhanova, K. (2021). ADRENALINE, AND WHAT PROCESSES OCCUR UNDER ITS ACTION IN OUR BODY. ГРААЛЬ НАУКИ, 398-401.