Final answer:
The general adaptation syndrome is a model describing the body's response to stress in three stages: alarm reaction, stage of resistance, and stage of exhaustion; as stress persists, the body's ability to cope diminishes, which can lead to serious health issues.
Step-by-step explanation:
General Adaptation Syndrome and Stress Responses
The general adaptation syndrome (GAS) is a model proposed by Hans Selye to describe the body's physiological response to stress. It consists of three stages.
1. Alarm Reaction
This initial stage is characterized by an immediate response to a threatening situation, often referred to as the fight-or-flight response. The body prepares for extreme physical exertion, mediated by hormones like epinephrine and norepinephrine, released from the adrenal medulla via the SAM pathway.
2. Stage of Resistance
If a stressor persists, the body enters the stage of resistance where the initial shock subsides and adaptation to the stressor begins. Here, the body remains on alert and is prepared to respond to the stressor but with less intensity. This is also the period where the body might adapt in specific ways, like sending signals to maximize nutrient absorption if a person is starving.
3. Stage of Exhaustion
During the stage of exhaustion, if the stress continues over a longer period, the body's ability to resist is depleted. Symptoms such as depression, immune suppression, severe fatigue, or even heart attacks may occur, which are mediated by hormones like cortisol from the adrenal cortex. Stress and its physiological responses have profound implications for health, potentially leading to conditions like hypertension and coronary artery disease. The GAS model significantly impacts our understanding of how stress can lead to physical ailments.