Figure 1.

Regulatory mechanism of stress response. The components highlighted in green are mainly affected by the hypothalamus–pituitary–adrenal axis, and those in yellow are mainly affected by the sympathetic–adrenal medulla axis. It is worth noting that only the main impact is presented, and there is a broader and more complex relationship between the two systems. The elements in red indicate the possible harm of stress. Stress can induce oxidative stress to cause ubiquitous damage to cells, tissues, and organs. ROS, reactive oxygen species; CRH, corticotropin-releasing hormone; AVP, arginine vasopressin; ACTH, adrenocorticotropic hormone.