What part of the body controls responses to stress?

The brain is the part of the body that controls responses to stress. It is the central organ responsible for processing emotions and regulating physiological reactions to stress through various mechanisms. When confronted with a stressor, the brain activates the hypothalamic-pituitary-adrenal (HPA) axis, which results in the release of stress hormones such as cortisol. This activation prepares the body to either fight or flee, a response commonly known as the "fight-or-flight" response.

In addition to hormonal responses, the brain also affects behavioral responses to stress. It processes sensory information and assesses threats, enabling individuals to react appropriately based on past experiences and learned behaviors. This complex interplay between emotional and cognitive functions makes the brain central to understanding how stress affects individuals physically and psychologically.

While the heart, muscles, and lungs all play important roles in physical responses to stress, they do so as part of the broader system managed by the brain. The heart rate may increase, muscles may tense, and breathing may become quicker as a result of signals sent from the brain. However, it is the brain that is essential in initiating and coordinating these responses.